Pathology of the Central Nervous System
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Questions and Answers

What type of cells are the functional and permanent constituents of the CNS?

  • Neuroglial cells
  • Ependymal cells
  • Neurons (correct)
  • Astrocytes

    • Which of the following cells is responsible for the formation of the blood-brain barrier?

  • Ependymal cells
  • Astrocytes (correct)
  • Microglial cells
  • Oligodendrocytes

    • What is the primary role of oligodendrocytes in the CNS?

  • Formation of scars
  • Phagocytosis of dead neurons
  • Myelination of neurons (correct)
  • Circulation of cerebrospinal fluid (CSF)

    • What is a characteristic feature of non-mitotic cells in the CNS?

    <p>They do not replace when the cell body is injured.</p> Signup and view all the answers

    Which process involves the death of neurons leading to the formation of a fluid-filled cyst?

    <p>Liquefactive necrosis</p> Signup and view all the answers

    Which type of CNS cell aggregates to form microglial nodules in response to insults?

    <p>Microglial cells</p> Signup and view all the answers

    What role do ependymal cells play in the central nervous system?

    <p>Production of cerebrospinal fluid</p> Signup and view all the answers

    What occurs after the injury to astrocytes in the CNS?

    <p>They form reactive gliosis.</p> Signup and view all the answers

    Which of the following is NOT a consequence of neuron injury?

    <p>Neurogenesis</p> Signup and view all the answers

    Which CNS cell type is involved in myelination and is affected in demyelinating diseases?

    <p>Oligodendrocytes</p> Signup and view all the answers

    What happens to the axon when the cell body of a CNS neuron is damaged?

    <p>The axon will die, and there will be no regeneration.</p> Signup and view all the answers

    Which type of cell is mainly responsible for supporting neurons?

    <p>Neuroglial cells</p> Signup and view all the answers

    What primarily distinguishes Wallerian degeneration from other forms of neuronal injury?

    <p>It involves the neurilemmal sheath of peripheral nerves.</p> Signup and view all the answers

    What does neuronophagy refer to?

    <p>Phagocytic activity by neuroglial cells.</p> Signup and view all the answers

    Which cell type is associated with the formation of scars in the CNS due to injury?

    <p>Astrocytes</p> Signup and view all the answers

    What is the primary role of ependymal cells in the CNS?

    <p>Production of cerebrospinal fluid (CSF)</p> Signup and view all the answers

    What is chromatolysis in the context of neurons?

    <p>An irreversible damage process in neurons.</p> Signup and view all the answers

    Which of the following describes permanent neurons? Pick two.

    <p>They are incapable of regeneration.</p> Signup and view all the answers

    What typically differentiates bacterial from viral meningitis with respect to glucose levels?

    <p>Viral meningitis shows no glucose metabolism.</p> Signup and view all the answers

    What is inclusion bodies in neurons associated with?

    <p>Infection or damage.</p> Signup and view all the answers

    Match the following types of cells with their characteristics:

    <p>Neurons = Functional cells, no replacement when damaged Astrocytes = Reactive gliosis equivalent to scar formation Oligodendrocytes = Myelination in the CNS Microglial cells = Monocytes and phagocytes in the CNS</p> Signup and view all the answers

    Match the following processes with their descriptions:

    <p>Chromatolysis = Irreversible damage to a neuron Wallerian degeneration = Distal axon segment dies after injury Neuronophagy = Removal of dead cells by neuroglial cells Leukodystrophy = Inability to maintain or produce myelin</p> Signup and view all the answers

    Match the following structures with their functions:

    <p>Ependymal cells = Production of cerebrospinal fluid Neurilemmal sheath = Support for peripheral axon regeneration Choroid plexus = Filtration of blood to produce CSF Inclusion bodies = Intracellular structures associated with infection</p> Signup and view all the answers

    Match the following types of neurotransmitter supporting cells with their origins:

    <p>Neuroglial cells = Origin of CNS tumors Astrocytes = Support for neuronal survival Oligodendrocytes = Myelination of CNS neurons Microglial cells = Reactive response to neuronal injury</p> Signup and view all the answers

    Match the following terms with their correct definitions:

    <p>Permanent cells = Do not undergo mitosis Labile cells = Cells that can regenerate quickly Stable cells = Cells that can divide under certain conditions CNS neurons = Do not regenerate after damage</p> Signup and view all the answers

    Which of the following is the primary cause of increased intracranial pressure?

    <p>Hydrocephalus</p> Signup and view all the answers

    What is a common clinical effect associated with increased intracranial pressure?

    <p>Headache</p> Signup and view all the answers

    Which of the following conditions is classified as primary CNS pathology?

    <p>Cerebral edema</p> Signup and view all the answers

    Which type of herniation is associated with displacement of the cingulate gyrus?

    <p>Subfalcine herniation</p> Signup and view all the answers

    Which of the following is NOT a cause of an increase in intracranial pressure?

    <p>Seizures</p> Signup and view all the answers

    Which secondary CNS pathology is characterized by a malfunction in blood flow?

    <p>Circulatory failure</p> Signup and view all the answers

    What is a potential outcome of increased intracranial pressure leading to brain herniation?

    <p>Optic atrophy</p> Signup and view all the answers

    What is the primary cause of secondary CNS disease?

    <p>Circulatory failures</p> Signup and view all the answers

    Which of the following best describes an ischemic stroke?

    <p>A lack of oxygen resulting from blocked blood flow</p> Signup and view all the answers

    Which condition is classified as an unprovoked and chronic neurological disorder?

    <p>Epilepsy</p> Signup and view all the answers

    What is a common consequence of a space-occupying lesion (SOL) in the CNS?

    <p>Seizures due to elevated intracranial pressure</p> Signup and view all the answers

    Which metabolic disorder can contribute to CNS disease?

    <p>Liver disease</p> Signup and view all the answers

    Which factor is NOT typically associated with secondary CNS pathology?

    <p>Genetic predispositions</p> Signup and view all the answers

    What distinguishes seizures from epilepsy?

    <p>Seizures are temporary events; epilepsy is a chronic disorder</p> Signup and view all the answers

    Match the following types of CNS disease with their descriptions:

    <p>Cerebral Vascular Accident = Commonly referred to as a stroke Epilepsy = An irreversible neurological disorder characterized by recurrent seizures SOL = A condition where the pressure in the skull is increased due to abnormal growths Thrombosis = A blockage in blood vessels due to blood clot formation</p> Signup and view all the answers

    Match the following causes of secondary CNS diseases with their categories:

    <p>Cardiac Disease = Circulatory Liver Disease = Metabolic Drug-induced Conditions = Chemical Hypoxemia = Circulatory</p> Signup and view all the answers

    Match the following terms related to ischemic stroke with their definitions:

    <p>Thrombus = A blood clot that can obstruct blood flow Hypoxemia = Deficiency of oxygen in the blood despite normal blood flow Infarct = An area of dead tissue due to lack of blood supply Cerebral Ischemia = Reduced blood flow to the brain leading to damage</p> Signup and view all the answers

    Match the following risk factors for CNS diseases with their implications:

    <p>Circulatory Failures = Account for 70% of secondary CNS diseases Metabolic Disorders = Are commonly due to liver and kidney diseases Acid-Base Disorders = Can lead to CNS dysfunction and contribute to seizures Space Occupying Lesions = Can increase intracranial pressure and cause neurological symptoms</p> Signup and view all the answers

    Which of the following contributes to secondary causes of CNS diseases? Match all that apply.

    <p>myocardial infarction</p> Signup and view all the answers

    Primary CNS pathologies, i.e. CVA, accounts for only 10% of the causes of CNS disease. Meanwhile, secondary CNS pathologies, i.e. cardiac disease, account for 90% of the causes of CNS disease.

    <p>True</p> Signup and view all the answers

    Which symptom is specifically associated with increased intracranial pressure?

    <p>Explosive headaches</p> Signup and view all the answers

    What is the primary clinical effect of papilledema?

    <p>Blurred optic disc margins</p> Signup and view all the answers

    Which herniation involves the cingulate gyrus pushing into the falx cerebri?

    <p>Subfalcine herniation</p> Signup and view all the answers

    Which clinical sign indicates a possible transtentorial herniation?

    <p>Ipsilateral eye dilation</p> Signup and view all the answers

    What is a common characteristic of headaches caused by increased intracranial pressure?

    <p>Sudden onset and explosive nature</p> Signup and view all the answers

    Which factor can lead to the development of pseudotumor cerebri in children?

    <p>Hypervitaminosis A</p> Signup and view all the answers

    What can result from increased intracranial pressure affecting the optic nerve?

    <p>Papilledema</p> Signup and view all the answers

    Which part of the brain is most at risk during tonsillar herniation?

    <p>Medulla oblongata</p> Signup and view all the answers

    What is a typical clinical indication of subfalcine herniation?

    <p>Contralateral limb weakness</p> Signup and view all the answers

    Which symptom is NOT typically associated with increased intracranial pressure?

    <p>Severe memory loss</p> Signup and view all the answers

    Match the following types of brain herniations with their descriptions:

    <p>Subfalcine = Herniation of cingulate gyrus into falx cerebri Transtentorial = Cerebral structures pushed downward compressing oculomotor nerve Tonsillar = Cerebellar tonsils herniate through foramen magnum Duret = Bleeding within the pons leading to locked-in syndrome</p> Signup and view all the answers

    Match the following clinical effects of increased intracranial pressure with their descriptions:

    <p>Explosive headaches = Sudden onset headache often associated with vomiting Papilledema = Blurred optic disc margins due to increased pressure Projectile vomiting = Vomiting not associated with nausea Hydrocephalus = Accumulation of cerebrospinal fluid leading to increased pressure</p> Signup and view all the answers

    Match the following signs of increased intracranial pressure with their implications:

    <p>Swelling of optic disc = Indicates papilledema Bradycardia = Abnormal heart rate often due to medulla compression Focal neurological deficits = Symptoms based on specific brain areas affected Dilated pupil = Common in transtentorial herniation affecting CN III</p> Signup and view all the answers

    Match the following causes of increased intracranial pressure to their descriptions:

    <p>Hematoma = Collection of blood pooling in the cranial cavity Infarction = Ischemic necrosis of brain tissue Pseudotumor cerebri = Increased ICP without an actual tumor Brain tumor = Space-occupying lesion causing ICP elevation</p> Signup and view all the answers

    Match the following cardiac symptoms with their associated conditions:

    <p>Headaches = Normal progression with pain and pressure Nausea = Often absent in ICP-related vomiting Neurological deficits = May arise from cerebral edema or herniation Atrophy of optic nerve = Chronic outcome from untreated papilledema</p> Signup and view all the answers

    Which level of consciousness indicates a state where a person needs stimulus to stay awake?

    <p>Stupor</p> Signup and view all the answers

    What is the primary characteristic that differentiates delirium from dementia? Pick two

    <p>Delirium is often due to a toxic state</p> Signup and view all the answers

    In non-communicating hydrocephalus, what is the most common congenital cause?

    <p>Aqueduct of Sylvius obstruction</p> Signup and view all the answers

    Which state of consciousness is characterized by drowsiness and indifference while the patient remains awake?

    <p>Lethargy</p> Signup and view all the answers

    What differentiates communicating hydrocephalus from non-communicating hydrocephalus?

    <p>Total obstruction versus failure of reabsorption</p> Signup and view all the answers

    Which of the following conditions is primarily associated with irreversible psychosis?

    <p>Dementia</p> Signup and view all the answers

    What is the primary cause of communicating hydrocephalus?

    <p>Acquired infection affecting CSF flow</p> Signup and view all the answers

    What manifestation is commonly seen with disorientation in patients with central nervous system issues?

    <p>Acid-base imbalance</p> Signup and view all the answers

    Which level of consciousness is defined as the state where a person cannot be awakened by any stimulus?

    <p>Coma</p> Signup and view all the answers

    Which manifestation describes a reversible mental disturbance often caused by a toxic state?

    <p>Delirium</p> Signup and view all the answers

    Match the levels of consciousness with their descriptions:

    <p>Alert = Fully awake and responsive Lethargy = Drowsy but can be aroused Stuporous = Requires stimulus to stay awake Comatose = Unresponsive to any stimuli</p> Signup and view all the answers

    Match the type of hydrocephalus with its characteristics:

    <p>Non-communicating hydrocephalus = Complete obstruction within the ventricular system Communicating hydrocephalus = Failure of reabsorption of cerebrospinal fluid Congenital causes = Commonly due to aqueductal obstruction Acquired causes = Often results from infections like meningitis</p> Signup and view all the answers

    Match the types of mental disturbance with their characteristics:

    <p>Delirium = Reversible mental disturbance often due to toxic states Dementia = Irreversible state of cognitive decline Disorientation = Inability to recognize time, place, or person Stupor = Near-unconscious state needing stimulus for awareness</p> Signup and view all the answers

    Match the conditions with their causes:

    <p>Delirium = Toxic metabolic syndrome Non-communicating hydrocephalus = Obstruction in the ventricular system Communicating hydrocephalus = Failure of arachnoid granulations Lethargy = Acid-base imbalance or drug influence</p> Signup and view all the answers

    Match the disturbances with their typical examples or indicators:

    <p>Lethargy = Patient shows drowsiness and disinterest Disorientation = Patient fails to recognize the current time Stupor = Patient requires loud noise to respond Coma = Patient does not react to painful stimuli</p> Signup and view all the answers

    Communicating hydrocephalus is more common than non-communicating hydrocephalus.

    <p>True</p> Signup and view all the answers

    An example of communicating hydrocephalus is a meningitis infection that leads to accumulation of WBC in the CSF.

    <p>True</p> Signup and view all the answers

    The most common cause of a non-communicating hydrocephalus is a congenital defect blocking the cerebral aqueduct.

    <p>True</p> Signup and view all the answers

    The choroid plexus is located at the floor of the lateral ventricles and the roof of the third and fourth ventricles.

    <p>True</p> Signup and view all the answers

    Hydrocephalus is an abnormal dilation of the ventricles of the brain, secondary to excess accumulation of cerebrospinal fluid (CSF).

    <p>True</p> Signup and view all the answers

    Which type of spina bifida is characterized by the protrusion of both the meninges and part of the spinal cord?

    <p>Myelomeningocele</p> Signup and view all the answers

    What condition describes a child born without cerebral hemispheres, yet retains the brain stem?

    <p>Anencephaly</p> Signup and view all the answers

    Which condition results from a stroke during delivery that affects one side of the body?

    <p>Infantile hemiplegia</p> Signup and view all the answers

    What is the primary consequence of severe hypoxia during labor for a full-term child?

    <p>Quadriplegia and severe mental retardation</p> Signup and view all the answers

    Which type of cerebral palsy is commonly associated with complications arising from prematurity?

    <p>Spastic diplegia</p> Signup and view all the answers

    What is a hallmark symptom of Arnold Chiari syndrome?

    <p>Severe headaches unresponsive to medications</p> Signup and view all the answers

    Which type of spina bifida typically has the least severe consequences and does not usually cause neurological problems?

    <p>Spina bifida occulta</p> Signup and view all the answers

    What is a common feature seen in children with anencephaly?

    <p>Frog-eyes and low-set ears</p> Signup and view all the answers

    What is the primary cause of damage leading to cerebral palsy at or shortly after birth?

    <p>Compression of the umbilical cord</p> Signup and view all the answers

    Which form of spina bifida involves only the protrusion of meninges without spinal cord involvement?

    <p>Meningocele</p> Signup and view all the answers

    Match the congenital malformation with its description:

    <p>Spina bifida occulta = Most minor, usually doesn’t cause neurological problems Myelomeningocele = Most serious case with spinal cord in the sac Anencephaly = Child born without cerebral hemispheres Cerebral palsy = Non-progressive motor pathology acquired at birth</p> Signup and view all the answers

    Match the condition with its associated sign or characteristic:

    <p>Spastic diplegia = Worst case quadriplegic &amp; severe mental retardation Arnold Chiari = Headaches that don’t respond to medications Infantile hemiplegia = Flexure contractions affecting one side of the body Meningocele = Protrusion of meninges through defect</p> Signup and view all the answers

    Match the congenital condition with its primary impact on the child:

    <p>Spina bifida = Incompleted closure of neural tube Cerebral palsy = Severe hypoxia during labor affects motor skills Anencephaly = Survival potential limited to days after birth Myelomeningocele = Paralysis below level of injury is common</p> Signup and view all the answers

    Match the description of congenital malformations with their names:

    <p>Seepage of CSF and indications of subcutaneous issues = Spina bifida occulta Developmental condition due to premature birth = Spastic diplegia Associated with herniation of cerebellar tonsils = Arnold Chiari Lack of cerebral hemispheres with a brain stem = Anencephaly</p> Signup and view all the answers

    Match the congenital malformation to its associated syndrome:

    <p>Myelomeningocele = Arnold Chiari syndrome Cerebral palsy = Flexure syndrome when learning to walk Anencephaly = Frog-eyes and low-set ears in presentation Spina bifida = Possible tuft of hair in lumbar region</p> Signup and view all the answers

    Spina bifida occulta is the most severe type of spina bifida and usually causes significant neurological problems.

    <p>False</p> Signup and view all the answers

    Children with myelomeningocele can be expected to be paralyzed below the level of their spinal cord injury.

    <p>True</p> Signup and view all the answers

    Anencephaly refers to a condition where a child is born with complete cerebral hemispheres and is expected to have a normal life span.

    <p>False</p> Signup and view all the answers

    Cerebral palsy is a progressive motor condition that worsens over time due to brain damage that occurs during or shortly after birth.

    <p>False</p> Signup and view all the answers

    Arnold Chiari syndrome is characterized by headaches that respond well to medication.

    <p>False</p> Signup and view all the answers

    What is Syringomyelia?

    <p>A condition characterized by a cyst filled with CSF in the dorsal column of the spinal cord</p> Signup and view all the answers

    Syringomyelia produces dissociated anesthesia in a cape-like distribution over the shoulders.

    <p>True</p> Signup and view all the answers

    Which of the following statements about Sturge-Weber Syndrome is true? (Select all that apply)

    <p>It involves cavernous hemangiomas that do not fade.</p> Signup and view all the answers

    Babies who are born with one crease in their palms are indicative of having Down's Syndrome.

    <p>False</p> Signup and view all the answers

    Match the following chromosomal abnormalities with their clinical features:

    <h1>Trisomy 21 = Aka Down's syndrome; protruding tongue and flat-bridged nose Trisomy 18 = Aka Edward's syndrome; rocker-bottom feet Trisomy 13 = Aka Patau; cyclopia</h1> Signup and view all the answers

    What is the most common type of stroke caused by a thrombus that forms at the site of the brain or an embolism that travels to the brain?

    <p>Ischemic stroke</p> Signup and view all the answers

    Which cells of the brain are at the highest risk for hypoxia during cerebral ischemia?

    <p>Pyramidal cells of the hippocampus</p> Signup and view all the answers

    What is the characteristic feature of a laminar infarct in the brain?

    <p>Affects layers or sections of gray matter</p> Signup and view all the answers

    What is the primary cause of a hemorrhagic stroke in relation to the Circle of Willis?

    <p>Aneurysm rupture</p> Signup and view all the answers

    Where is the most common location for a single congenital Berry aneurysm to occur?

    <p>Anterior communicating artery</p> Signup and view all the answers

    What is one consequence of a ruptured aneurysm in the context of cerebrovascular diseases?

    <p>Formation of a subarachnoid hemorrhage</p> Signup and view all the answers

    Which type of malformation occurs when small arterioles drain directly into venules without capillaries, potentially leading to rupture?

    <p>Arteriovenous malformation</p> Signup and view all the answers

    In which location are Micro-Charcot-Bouchard aneurysms most commonly found?

    <p>Where the parietal meets the occipital lobe</p> Signup and view all the answers

    What is the survival rate immediately after a patient experiences a hemorrhagic stroke due to the rupture of a vessel?

    <p>10-15%</p> Signup and view all the answers

    What is a key characteristic of watershed infarcts in the brain?

    <p>Arise from a lack of blood supply from two branches</p> Signup and view all the answers

    Match the following types of strokes with their characteristics:

    <p>Ischemic Stroke = Caused by blockage of blood flow leading to tissue necrosis Hemorrhagic Stroke = Results from a rupture of a blood vessel Global Ischemia = Affects an entire section of the brain Regional Ischemia = Affects a specific area due to thrombus or embolism</p> Signup and view all the answers

    Match the following types of aneurysms with their descriptions:

    <p>Berry Aneurysm = Common in the circle of Willis and can rupture spontaneously Micro-Charcot-Bouchard Aneurysm = Associated with hypertension and located in gray matter Atherosclerotic Aneurysm = Often found on larger vessels Congenital Aneurysm = Originates from weakness in blood vessel walls</p> Signup and view all the answers

    Match the following infarct types with their characteristics:

    <p>Watershed Infarct = Caused by insufficient blood supply due to blockage of 1 branch Laminar Infarct = Results from blockage of penetrating arteries affecting gray matter layers Thromboembolism = Most common type of stroke that travels to the brain Regional Infarct = Localized effect due to thrombus formed at stroke site</p> Signup and view all the answers

    Match the following cells with their vulnerability to hypoxia:

    <p>Pyramidal cells = Located in the Sommers sector of the hippocampus Purkinje cells = Found in the cerebellum and susceptible to lack of oxygen Neurons in gray matter = Affected by Micro-Charcot-Bouchard aneurysms Endothelial cells = Involved in blood vessel formation and can be compromised</p> Signup and view all the answers

    Match the following vascular malformations with their features:

    <p>Arteriovenous Malformations = Direct connection between arterioles and venules without capillaries Intracerebral Hemorrhagic = Related to hypertension and may occur with Micro-Charcot-Bouchard Circle of Willis Malformation = Most aneurysms are formed here due to vascular weakness Congenital Aneurysm = Formed due to structural weakness in vessel walls over time</p> Signup and view all the answers

    Match the type of condition with their most common location:

    <p>Congenital Berry aneurysm = anterior communicating artery Charcot-Bouchard aneurysm = where the parietal lobe meets the occipital lobe atherosclerotic aneurysm = larger vessels within the Circle of Willis Hemorrhagic stroke = subarachnoid space regional infarct = thromboembolism watershed infarct = parasagittal location where brain receives blood from multiple branches laminar infarct = penetrating artery branches from superficial arteries</p> Signup and view all the answers

    What is a defining feature of a concussion?

    <p>Transient loss of consciousness</p> Signup and view all the answers

    What type of hematoma is associated with the rupture of the middle meningeal artery?

    <p>Epidural hematoma</p> Signup and view all the answers

    Which type of spinal cord injury results from the head being thrown back?

    <p>Hyperextension injury</p> Signup and view all the answers

    What is the consequence of a coup contusion?

    <p>Bruising directly under the site of impact</p> Signup and view all the answers

    What type of amnesia is characterized by an inability to remember events prior to trauma?

    <p>Retrograde amnesia</p> Signup and view all the answers

    Which mechanism primarily causes increases in intracranial pressure (ICP) in low-velocity penetrating trauma?

    <p>Slow bleeding and edema</p> Signup and view all the answers

    Which symptom may occur as a result of a hemisection injury of the spinal cord?

    <p>Contralateral loss of temperature sensation</p> Signup and view all the answers

    In which scenario would an epidural hematoma likely develop?

    <p>Direct blow to the temporal region</p> Signup and view all the answers

    What differentiates acute subdural hematomas from chronic subdural hematomas?

    <p>Acute hematomas result from arterial bleed while chronic are venous</p> Signup and view all the answers

    Match the following types of CNS trauma with their descriptions:

    <p>Blunt force trauma = Trauma to brain without penetration of the skull Epidural hematoma = Accumulation of blood between dura mater and skull Subdural hematoma = Venous bleed affecting dural venous sinuses Penetrating trauma = Injury resulting from an object entering the skull</p> Signup and view all the answers

    Match the following types of amnesia with their characteristics:

    <p>Retrograde amnesia = Can't remember events prior to trauma Anterograde amnesia = Can't remember events after trauma CTE = Chronic traumatic encephalopathy similar to Alzheimer's Concussion = Transient loss of conscious awareness</p> Signup and view all the answers

    Match the following spinal cord injuries with their effects:

    <p>Hyperextension = Posterior contusion affecting dorsal columns Hyperflexion = Anterior contusion leading to a teardrop fracture Hemisection of the cord = Ipsi paralysis &amp; contralateral loss of pain Ruptured ALL = Injury associated with hyperextension trauma</p> Signup and view all the answers

    Match the following brain injury types with their definitions:

    <p>Coup = Bruising directly under site of trauma Contrecoup = Injury to the occipital lobe from frontal impact Contusion = Bruising of the brain tissue itself Chronic hematoma = More common than acute in subdural bleeds</p> Signup and view all the answers

    Match the following types of injuries with their velocity characteristics:

    <p>High velocity = Entry &amp; exit wound with rapid ICP increase Low velocity = May cause bleeding &amp; edema along bullet path Blunt trauma = No penetration, causes disruption of brain function Penetrating injury = Injury resulting in direct damage from a projectile</p> Signup and view all the answers

    What is the primary causative organism of the most serious type of bacterial meningitis?

    <p>Neisseria meningitidis</p> Signup and view all the answers

    Which of the following is a common clinical sign of acute bacterial meningitis?

    <p>Stiff neck</p> Signup and view all the answers

    How does viral encephalitis primarily differ from viral meningitis?

    <p>Viral encephalitis can lead to death and neurological defects</p> Signup and view all the answers

    Which vaccine is most effective in preventing meningococcal meningitis caused by Neisseria meningitidis?

    <p>Meningococcal conjugate vaccine</p> Signup and view all the answers

    Which sign is associated with meningeal irritation observed in suspected meningitis cases?

    <p>Brudzinski's sign</p> Signup and view all the answers

    What hallmark finding would you expect in the cerebrospinal fluid (CSF) of a patient with bacterial meningitis?

    <p>Cloudy appearance from pus cells</p> Signup and view all the answers

    What long-term effect can result from parenchymal syphilis caused by Treponema pallidum?

    <p>General paresis and dementia</p> Signup and view all the answers

    Which condition is indicated by the presence of perivascular cuffing in the brain?

    <p>Viral encephalitis</p> Signup and view all the answers

    What is a typical feature of viral meningitis when compared to bacterial meningitis?

    <p>Self-limiting course</p> Signup and view all the answers

    What is the primary treatment requirement for bacterial meningitis?

    <p>Immediate hospitalization and antibiotics</p> Signup and view all the answers

    Match the following types of meningitis with their characteristics:

    <p>Bacterial meningitis = Causes increased pus cells and requires treatment Viral meningitis = Resembles a cold and usually resolves on its own Chronic meningitis = Often associated with tuberculosis and caseous granulomatous formation Acute viral meningitis = Involves lymphocytes attacking the infection</p> Signup and view all the answers

    Match the following features of viral encephalitis with their definitions:

    <p>Perivascular cuffing = Accumulation of lymphocytes around blood vessels Neuronophagia = Destruction of neurons by a viral agent Reactive gliosis = Astrocytes form a scar-like response to injury Inclusion bodies = Pathological structures formed in infected neurons</p> Signup and view all the answers

    Match the following types of neurosyphilis with their descriptions:

    <p>Meningovascular syphilis = Fuses meninges together due to chronic inflammation Parenchymal syphilis = Causes progressive dementia and psychosis Tabes dorsalis = Loss of sensation in limbs leading to characteristic gait General paresis = Results from prolonged infection leading to severe brain atrophy</p> Signup and view all the answers

    Match the following routes of CNS infection with their examples:

    <p>Hematogenous = Infection through blood (bacteremia or viremia) Direct local infection = Infection from sinusitis or otitis media Penetrating injuries = Infections from fractures leading to rhinorrhea or otorrhea Post-infection sequelae = Neurosyphilis and its complications</p> Signup and view all the answers

    Match the following conditions of bacterial meningitis with their signs:

    <p>Increased protein and decreased glucose in CSF = Typical finding in acute bacterial meningitis Suppurative = Attacking neutrophils causes increased pus cells Cloudy CSF = Indicates presence of pus cells Positive Brudzinski's sign = Indicates irritation of meninges when head flexed</p> Signup and view all the answers

    Match the meningitis test with the positive sign:

    <p>Brudzinski's sign = Flexing the head causes the knees to flex as a reflex Kernig's sign = Extending the leg and knee causes pain due to meningeal irritation</p> Signup and view all the answers

    Meningococcal meningitis can lead to DIC. Which of the following is characteristic of DIC?

    <p>Bilateral bleeding in the adrenal glands</p> Signup and view all the answers

    Neurosyphilis is a tertiary syphilis. Match the progression of disease with its symptoms:

    <p>a) Meningovascular syphilis = 3 years from infection b) Meningovascular syphilis = Causes meninges to fuse together due to chronic inflammation c) Meningovascular syphilis = Causes compression of cranial nerves that pass through the subarachnoid space d) Parenchymal syphilis = 10 years from infection e) Parenchymal syphilis = Causes General Paresis that leads to progressive dementia and psychosis f) Parenchymal syphilis = Causes Tabes Dorsalis that leads to a slapping gait</p> Signup and view all the answers

    What type of viral infection is primarily associated with hemorrhagic necrotizing encephalitis in adults?

    <p>Herpes simplex encephalitis</p> Signup and view all the answers

    Which disease is characterized by a high mortality rate and can lead to slow progressive dementia after initial contraction?

    <p>Subacute sclerosing panencephalitis</p> Signup and view all the answers

    Which viral infection is commonly associated with perivascular cuffing and multinucleated giant cells?

    <p>HIV encephalitis</p> Signup and view all the answers

    What is the transmission method for poliomyelitis?

    <p>Fecal-oral route</p> Signup and view all the answers

    Which of the following is a feature of rabies infection?

    <p>Necrotizing encephalitis</p> Signup and view all the answers

    What pathological feature is characteristic of severe cases of prion diseases?

    <p>Spongiform changes in gray matter</p> Signup and view all the answers

    How does primary amoebic meningoencephalopathy typically present in terms of outcomes?

    <p>100% fatal</p> Signup and view all the answers

    What is a unique diagnostic feature of rabies infection?

    <p>Negri body</p> Signup and view all the answers

    What is often the first clinical sign of acute poliomyelitis?

    <p>Muscle weakness</p> Signup and view all the answers

    Which viral infection is known to primarily affect ependymal cells and is common in neonates?

    <p>Cytomegalovirus</p> Signup and view all the answers

    Match the following viral infections with their characteristics:

    <p>Herpes simplex encephalitis = Produces hemorrhagic necrotizing encephalitis in temporal lobes Cytomegalovirus = Causes infection commonly in neonates Subacute sclerosing panencephalitis = Leads to slow progressive dementia HIV encephalitis = Effects mostly seen in the white matter and basal ganglia</p> Signup and view all the answers

    Match the following conditions with their transmission methods:

    <p>Poliomyelitis = Fecal-oral route Rabies = Transmission through animal bites Toxoplasmosis = Transmission through feline feces Naegleria Fowleri = Contamination from freshwater sources</p> Signup and view all the answers

    Match the following diseases with their specific diagnostic features:

    <p>Herpes simplex encephalitis = Intranuclear inclusion bodies called Cowdry body Rabies = Eosinophilic cytoplasmic inclusion bodies Prion encephalopathies = Proteinaceous infectious particles Cytomegalovirus = Perivascular cuffing and enlarged neurons</p> Signup and view all the answers

    Match the following complications with their associated diseases:

    <p>Subacute sclerosing panencephalitis = 80% mortality rate Rabies = Phalangeal paralysis Toxoplasmosis = 3rd trimester issues in pregnancy Poliomyelitis = Lower motor paralysis without sensory loss</p> Signup and view all the answers

    Match the following viral diseases with their common vectors or causes:

    <p>West Nile encephalitis = Mosquito vector Cytomegalovirus = Common in neonates Human immunodeficiency virus (HIV) = Effects include multinucleated giant cells Subacute sclerosing panencephalitis = Related to rubeola (measles) infection</p> Signup and view all the answers

    Match the following neurological conditions with their associated characteristics:

    <p>HSV-1 = Causes hemorrhagic necrotizing encephalitis in temporal lobe HSV-1 = Cowdry body Cytomegalovirus = Common in neonates affecting ependymal cells Cytomegalovirus = Causes perivascular cuffing, glial nodules, and enlarged neurons Subacute sclerosing panencephalitis = Causes slow progressing dementia in children 7 or younger Subacute sclerosing panencephalitis = Affects neurons in cerebral gray matter of frontal lobe and basal ganglia</p> Signup and view all the answers

    Match the following conditions with their characteristics:

    <p>Arbovirus infections = Due to mosquito vector and classified as a Flaviviridae that causes jaundice HIV encephalitis = Effects include perivascular cuffing, glial nodules, and multinucleated giant cells, with changes most commonly occurring in the white matter and basal ganglia</p> Signup and view all the answers

    Which statement best describes congenital leukodystrophies?

    <p>They are characterized by genetic disorders affecting myelin maintenance.</p> Signup and view all the answers

    What is the primary cause of adrenal insufficiency in Adrenoleukodystrophy?

    <p>Excessive production of VLC fatty acids.</p> Signup and view all the answers

    Which of the following is a characteristic feature of Multiple Sclerosis?

    <p>Plauquing of demyelination is most common in periventricular regions.</p> Signup and view all the answers

    Which viral infection is most commonly associated with Acute Disseminated Encephalomyelitis (ADEM)?

    <p>Rubella</p> Signup and view all the answers

    In the context of Progressive Multifocal Leukoencephalopathy, which statement is accurate?

    <p>It is caused by the JC virus and attacks oligodendrocytes.</p> Signup and view all the answers

    Which feature is indicative of Pernicious Anemia?

    <p>It involves destruction of parietal cells in the stomach.</p> Signup and view all the answers

    What is a common neurological symptom caused by Multiple Sclerosis?

    <p>Unilateral visual loss due to optic neuritis.</p> Signup and view all the answers

    How does Acute Disseminated Encephalomyelitis differ from Multiple Sclerosis?

    <p>ADEM typically occurs after a viral infection.</p> Signup and view all the answers

    What condition is characterized by megaloblastic macrocytic anemia due to vitamin B12 deficiency?

    <p>Pernicious Anemia</p> Signup and view all the answers

    Which type of immune response is associated with the etiology of Multiple Sclerosis?

    <p>Type IV hypersensitivity.</p> Signup and view all the answers

    Match the following demyelinating diseases with their characteristics:

    <p>Multiple sclerosis = Most common acquired demyelinating disease of CNS Metachromatic leukodystrophy = Most common in infants with progressive symptoms Adrenoleukodystrophy = X-linked recessive disorder leading to adrenal insufficiency Progressive multifocal leukoencephalopathy = Caused by JC virus, seen in immunocompromised patients</p> Signup and view all the answers

    Match the following conditions with their causes:

    <p>Acute disseminated encephalomyelitis = Occurs after an infection Pernicious anemia = Autoimmune destruction of parietal cells Adrenoleukodystrophy = Presence of very long-chain fatty acids Multiple sclerosis = T-cell mediated type IV hypersensitivity</p> Signup and view all the answers

    Match the following symptoms or findings with their associated conditions:

    <p>Loss of special senses = Metachromatic leukodystrophy Lymphocytic perivascular cuffing = Acute disseminated encephalomyelitis Unilateral visual loss = Multiple sclerosis Neurological deficits = Progressive multifocal leukoencephalopathy</p> Signup and view all the answers

    Match the following demyelinating disease features with their descriptions:

    <p>Leukodystrophies = Genetic disorders affecting myelin Acute disseminated encephalomyelitis = Monophasic condition post-infection Multiple sclerosis = Plaquing of demyelination in periventricular areas Pernicious anemia = Megaloblastic macrocytic anemia due to B12 deficiency</p> Signup and view all the answers

    Match the following demyelinating diseases with their demographic associations:

    <p>Multiple sclerosis = Most common in Scandinavians Metachromatic leukodystrophy = Most common in infants Adrenoleukodystrophy = Associated with X-linked inheritance Progressive multifocal leukoencephalopathy = Common in AIDS patients</p> Signup and view all the answers

    What is the most common cause of dementia?

    <p>Alzheimer's disease</p> Signup and view all the answers

    In which order do the symptoms of Pick disease manifest?

    <p>Personality changes, speech difficulties, memory loss</p> Signup and view all the answers

    Which pathology is characteristic of Parkinson's disease?

    <p>Lewy bodies in neurons</p> Signup and view all the answers

    What is the primary neurotransmitter affected in Huntington's disease?

    <p>GABA</p> Signup and view all the answers

    What is a common symptom of spinocerebellar degeneration?

    <p>Intention tremor</p> Signup and view all the answers

    What is the primary cause of death associated with Friedreich ataxia?

    <p>Hypertrophic cardiomyopathy</p> Signup and view all the answers

    Which sign is commonly associated with Amyotrophic lateral sclerosis (ALS)?

    <p>Stooped posture</p> Signup and view all the answers

    What is one of the first areas affected by degeneration in Amyotrophic lateral sclerosis?

    <p>Anterior horn cells</p> Signup and view all the answers

    In which brain regions does Pick disease typically present pathology?

    <p>Dominant frontal and temporal lobes</p> Signup and view all the answers

    What clinical feature is primarily associated with the decline of GABA in Huntington's disease?

    <p>Decreased motor coordination</p> Signup and view all the answers

    Match the following degenerative diseases with their corresponding signs:

    <p>Alzheimer's disease = Memory loss occurs first, followed by personality disorders, then speech loss Pick disease = Personality changes occur first, followed by speech, then memory loss Huntington's disease = Delusional thinking, paranoia, personality changes Parkinson's disease = Shuffling gait, stooped posture, mask-like face, resting tremor</p> Signup and view all the answers

    Match the following conditions with their primary pathological features:

    <p>Amyotrophic lateral sclerosis (ALS) = Injury to both upper and lower motor neuron tracts Huntington's disease = Overall depletion of GABA Spinocerebellar degeneration = Degeneration of multiple tracts of brainstem &amp; spinal cord Alzheimer's disease = Senile plaques of beta-amyloid</p> Signup and view all the answers

    Match the following degenerative diseases with their typical pathology:

    <p>Parkinson's disease = Loss of dopamine secreting neurons in substantia nigra Pick disease = Affects dominant side of frontal and temporal lobes Huntington's disease = Atrophy of caudate nucleus Spinocerebellar degeneration = Hypertrophic cardiomyopathy as the most common cause of death</p> Signup and view all the answers

    Match the following diseases with their common onset age:

    <p>Parkinson's disease = Typically onset in middle-aged adults Huntington's disease = Onset begins around late 30's to early 40's Spinocerebellar degeneration = Onset begins around adolescence Alzheimer's disease = Onset usually occurs in older adults</p> Signup and view all the answers

    Match the following conditions with their associated clinical features:

    <p>Alzheimer's disease = Congophilic angiopathy leading to fibrinoid necrosis Parkinson's disease = Contains Lewy bodies in neurons Spinocerebellar degeneration = Ataxia &amp; intention tremor if affecting cerebellum Amyotrophic lateral sclerosis (ALS) = Flaccid paralysis from lower motor neuron injury</p> Signup and view all the answers

    What is the primary enzyme deficiency in phenylketonuria (PKU)?

    <p>Phenylalanine hydroxylase</p> Signup and view all the answers

    Which of the following is a distinguishing feature of Tay-Sachs disease?

    <p>Cherry red spot on macula</p> Signup and view all the answers

    What specific symptom is associated with Wilson disease?

    <p>Kayser-Fleischer rings</p> Signup and view all the answers

    Which of the following disorders is primarily linked to alcohol withdrawal?

    <p>Wernicke-Korsakoff syndrome</p> Signup and view all the answers

    What is the consequence of a deficiency in vitamin B1 in Wernicke-Korsakoff syndrome?

    <p>Brain stem lesions</p> Signup and view all the answers

    Which of the following is a symptom of hepatic encephalopathy?

    <p>Confusion and disorientation</p> Signup and view all the answers

    In Niemann-Pick disease, what substance accumulates in the body?

    <p>Sphingomyelin</p> Signup and view all the answers

    Subacute combined degeneration of the spinal cord is primarily caused by a deficiency in which vitamin?

    <p>Vitamin B12</p> Signup and view all the answers

    Which condition is characterized by accumulation of ammonia in the blood?

    <p>Hepatic encephalopathy</p> Signup and view all the answers

    Which of the following signifies deterioration that begins at around 6 months in newborns?

    <p>Tay-Sachs disease</p> Signup and view all the answers

    Match the following inherited metabolic disorders with their characteristics:

    <p>Phenylketonuria (PKU) = Lack of enzyme phenylalanine hydroxylase Tay-Sachs disease = Lysosomal storage disease with cherry red spot on macula Niemann-Pick disease = Sphingomyelin disorder with visceromegaly Wilson disease = Excess copper accumulation with Kayser-Fleischer rings</p> Signup and view all the answers

    Match the following acquired metabolic disorders with their symptoms:

    <p>Wernicke-Korsakoff syndrome = Confusion and ataxia with alcohol withdrawal Hepatic encephalopathy = High ammonia levels leading to coma Subacute combined degeneration = B12 deficiency leading to myelin loss Korsakoff psychosis = Anterograde amnesia and lack of grooming skills</p> Signup and view all the answers

    Match the following symptoms with their associated disorders:

    <p>Cherry red spot on macula = Tay-Sachs disease Visceromegaly = Niemann-Pick disease Kayser-Fleischer rings = Wilson disease Retrograde amnesia = Korsakoff psychosis</p> Signup and view all the answers

    Match the following metabolic disturbances with their causes:

    <p>Wernicke's encephalopathy = Vitamin B1 deficiency Hepatic encephalopathy = High BUN levels Phenylketonuria = Lack of phenylalanine hydroxylase Subacute combined degeneration = B12 deficiency</p> Signup and view all the answers

    Match the following descriptions with the correct condition:

    <p>Confused, drowsy, disorientation = Wernicke-Korsakoff syndrome Accumulation of glucocerebroside = Tay-Sachs disease Presence of visceromegaly = Niemann-Pick disease Chronic copper toxicity = Wilson disease</p> Signup and view all the answers

    Which type of glioma is most aggressive and can cross the midline?

    <p>Glioblastoma multiforme</p> Signup and view all the answers

    What is the primary characteristic of meningiomas?

    <p>They are benign and typically compress surrounding tissue.</p> Signup and view all the answers

    In which demographic is medulloblastoma most frequently diagnosed?

    <p>Children under 10 years old</p> Signup and view all the answers

    What is a typical presentation of Guillain-Barre Syndrome?

    <p>Ascending paralysis beginning with tingling in extremities.</p> Signup and view all the answers

    What type of tumors are primarily associated with neurofibromatosis Type I?

    <p>Benign skin and peripheral nerve tumors</p> Signup and view all the answers

    Which of the following characteristics is associated with juvenile pilocytic astrocytoma?

    <p>Very operable with good prognosis.</p> Signup and view all the answers

    Which cancer is most commonly associated with brain metastases?

    <p>Lung cancer</p> Signup and view all the answers

    What is the primary presenting symptom of Myasthenia gravis?

    <p>Ptosis and diplopia from descending paralysis.</p> Signup and view all the answers

    Craniopharyngiomas are most commonly found in which age group?

    <p>Teens to early 20's.</p> Signup and view all the answers

    What initial symptoms are associated with diabetic neuropathy?

    <p>Burning sensation in the feet.</p> Signup and view all the answers

    Match the following nervous system tumors with their characteristics:

    <p>Glioblastoma multiforme = Grade 4 malignant astrocytoma Meningioma = Benign tumor causing compression Medulloblastoma = Originates in the cerebellum, seen in children Oligodendroglioma = Derived from oligodendrocytes, can show calcifications</p> Signup and view all the answers

    Match the following peripheral nervous system disorders with their descriptions:

    <p>Guillain-Barre Syndrome = Ascending paralysis after viral infection Myasthenia gravis = Descending paralysis affecting facial muscles Trigemininal neuralgia = Pain triggered by light touch to the face Diabetic neuropathy = Numbness in feet with burning sensation</p> Signup and view all the answers

    Match the following types of neurofibromatosis with their characteristics:

    <p>Type I Neurofibromatosis = Von Recklinghausen disease with skin tumors Type II Neurofibromatosis = Bilateral acoustic neuromas leading to deafness Café au lait spots = Pigmented lesions associated with Type I Acoustic neuromas = Tumors that can compress facial nerve</p> Signup and view all the answers

    Match the following CNS tumors with the demographics they most commonly affect:

    <p>Juvenile pilocytic astrocytoma = Derived from astrocytes and is very operable in children under 10 Medulloblastoma = Highly malignant and can metastasize through the CSF Craniopharyngioma = Mostly contains cholesterol crystal calcifications and is located on the sella turcica Ependymoma = When located in the brain, the tumor will show in the 4th ventricle</p> Signup and view all the answers

    Match the following tumors with their origins:

    <p>Astrocytoma = Derived from astrocytes Ependymoma = Derived from ependymal cells lining ventricles Lymphoma = Primary brain tumor of B lymphocyte type Secondary neoplasm = Metastasis to the brain</p> Signup and view all the answers

    Study Notes

    Central Nervous System

    • The central nervous system (CNS) consists of the brain and spinal cord.
    • The functional cells of the nervous system are neurons.
    • Neurons are non-mitotic, meaning they cannot divide and replace themselves.
    • Injuries to neurons can result in:
      • Chromatolysis: Loss of Nissl substance (rough endoplasmic reticulum).
      • Pyknosis: Nuclear shrinkage and condensation.
      • Wallerian degeneration: Degradation of the axon distal to the injury site.
      • Neuronophagia: Phagocytosis of damaged neurons by microglial cells.
      • Inclusion bodies: Abnormal accumulations of material within a neuron's cytoplasm or nucleus.
    • Neuron death leads to liquefactive necrosis and fluid-filled cyst formation.
    • Neuroglial cells are supporting cells in the CNS.
      • Astrocytes are responsible for the blood-brain barrier and contribute to scar formation.
      • Oligodendrocytes are responsible for myelination in the CNS.
      • Ependymal cells line the ventricles and central canal, contributing to CSF circulation.
        • Choroid plexus capillaries found in these areas produce CSF.
      • Microglial cells are the phagocytes of the CNS.
        • Microglial nodules form in response to injury and can become foamy macrophages known as Gitter cells.

    Neurons

    • Functional cells of the nervous system
    • Cannot be replaced if damaged
      • Axons can be repaired, but if the cell body is damaged, repair is not possible
      • Permanent cells do not undergo mitosis
      • Lack of mitosis in CNS neurons means there are no tumors with mature neurons
    • Chromatolysis/ pyknosis describes irreversibly damaged neurons
    • Wallerian degeneration:
      • Occurs in the distal 'stump' of a cut peripheral nerve
      • Neurilemmal sheath only found on axons of peripheral nerves, NOT in CNS
      • Proximal 'stump' can form a new axon if the soma can support it
      • Peripheral neurons can regrow due to neurilemmal sheaths, but CNS neurons cannot
    • Neuronophagy is the phagocytic activity of neuroglial cells removing dead neurons
    • Inclusion bodies:
      • Found within the soma
      • Often seen in nerves infected by herpes virus

    Neuroglial Cells

    • Supporting cells of the nervous system
    • Required for neuron survival
    • Replicate and can form tumors
    • Astrocytes:
      • No fibrous material in the brain, but reactive gliosis is equivalent to scar formation
    • Oligodendrocytes:
      • Equivalent to Schwann cells in the periphery
      • Leukodystrophy is a primary disorder where cells cannot make or maintain myelin
    • Ependymal cells:
      • Choroid plexus creates CSF
        • Located within the floor of lateral ventricles and roof of the 3rd ventricle
        • CSF is an ultrafiltrate of blood made up of water, glucose, and protein
      • Bacteria metabolize glucose, viruses do not
        • Glucose levels in CSF can differentiate between viral and bacterial meningitis
    • Microglial cells:
      • Monocytes/ phagocytes of the CNS
      • Part of the mononuclear phagocytic system

    Neurons

    • Functional cells of the nervous system
    • No regenerative capacity if the cell body is damaged
      • Axon can be repaired
      • Cells are classified as labile, stable, or permanent
        • Permanent cells do not undergo mitosis
    • Absence of tumors/ neoplasms with mature neurons due to lack of mitosis
    • Chromatolysis/ pyknosis: Term for irreversibly damaged neuron
    • Wallerian degeneration: Degeneration of the distal part of an axon after injury
      • Occurs in peripheral nerves, not in the CNS
      • The neurilemmal sheath is only found on axons of peripheral nerves, not in the CNS
      • The proximal stump can form a new axon if the soma can support it
      • Note: Peripheral neurons can regrow due to the neurilemmal sheath, but CNS neurons cannot
    • Neuronophagy: Phagocytic activity of neuroglial cells to remove dead neurons
    • Inclusion bodies: Structures found within the soma, cytoplasm, or nucleus
      • Herpes virus infections are often found within the nucleus

    Neuroglial cells

    • Stromal matrix cells (supporting cells) of the neuron
    • Necessary for survival/ support of neurons
    • Capable of replication, tumors of neuroglial origin, not neurons
    • Astrocytes: Responsible for reactive gliosis, which is similar to scar formation
    • Oligodendrocytes: Myelinating cells of the CNS (equivalent to Schwann cells in the periphery)
      • Leukodystrophy: Disorders affecting the production and maintenance of myelin
    • Ependymal cells: Line the ventricles of the brain and the central canal of the spinal cord
      • Choroid plexus: Specialized capillaries within the floor of the lateral ventricles and the roof of the third ventricle, responsible for producing CSF
        • CSF is an ultrafiltrate of blood, composed of water, glucose, and protein
      • Bacteria metabolize glucose, viruses do not
        • Differentiating viral vs bacterial meningitis is done by examining glucose levels in the CSF
    • Microglial cells: Monocytes/ phagocytes of the CNS
      • Part of the mononuclear phagocytic system
      • Mononuclear phagocytic: The microglial cell is the phagocyte within the CNS

    Causes of CNS Disease

    • Primary CNS Pathology (10%)
      • Cerebrovascular Accident (CVA)
      • Epilepsy (Seizures)
      • Trauma
      • Tumors
      • Infections
      • Cerebral Edema
    • Secondary CNS Pathology (90%)
      • Circulatory failure
      • Cardiac disease
      • Metabolic causes
      • Chemical Causes

    Manifestations of CNS Disease

    • Cerebral Edema with Increased Intracranial Pressure (ICP)
      • Causes of increased ICP
        • Tumor
        • Infections
        • Hemorrhage or Hematoma
        • Infarction
        • Trauma
        • Hydrocephalus
        • Pseudotumor cerebri
      • Clinical effects of increased ICP
        • Headache
        • Vomiting
        • Papilledema - optic atrophy
        • Altered consciousness, seizures, bradypnea, bradycardia, with increased systolic and decreased diastolic blood pressure, personality changes, cranial nerve palsies.
    • Brain Herniations
      • An increase in ICP can lead to herniation of intracranial CNS structures and eventually develop "false localizing signs".
        • Subfalcine (cingulate gyrus) herniation:
        • Transtentorial (uncinate) herniation:
        • Tonsillar herniation:
        • Caudal shift of brain stem: Duret hemorrhage

    Causes of CNS Disease

    • Primary causes account for only 10% of CNS diseases.
    • Secondary causes account for 90% of CNS diseases.
    • 70% of secondary CNS disease cases are caused by circulatory failures.

    Primary CNS Diseases

    • Cerebral vascular accident (CVA), also known as a stroke, is a primary CNS disease.
      • Ischemic stroke occurs due to a lack of oxygen due to blockage of blood flow.
        • A thrombus, tumor, or other obstruction can lead to ischemic necrosis, also known as an infarct.
        • Hypoxemia is a lack of oxygen in the blood, despite adequate blood flow. This can be caused by compressed breathing or carbon monoxide poisoning.
    • Epilepsy is characterized by recurrent seizures.
      • Epilepsy is idiopathic, irreversible, and a lifelong condition.
      • A seizure is a temporary event caused by abnormal electrical activity in the brain. This can be triggered by trauma, drugs, or acid-base disorders.
    • Space-occupying lesions (SOLs) are any mass that increases intracranial pressure, which can lead to seizures.

    Secondary CNS Diseases

    • Circulatory problems are the most common cause of secondary CNS diseases (90%).
      • Thrombosis within the heart can travel through the common carotid artery to the internal carotid artery, causing a stroke.
      • Cardiac disease, such as a myocardial infarction, can lead to impaired blood flow to the brain, resulting in hypoxemia.
    • Metabolic diseases, such as liver and kidney disease, can also contribute to CNS disease.
    • Chemical imbalances, such as drugs, imbalances in acids and bases, and fluid disorders affecting osmolarity, can lead to swelling and affect the CNS.

    Causes of CNS Disease

    • Primary CNS disease accounts for only 10% of cases.
    • Secondary CNS disease accounts for 90% of cases, with 70% being due to circulatory failures.
    • Cerebral Vascular Accident (CVA) is a primary cause of CNS disease.
      • Also known as a stroke.
      • Ischemic stroke occurs due to a lack of oxygen due to a lack of blood flow.
        • A thrombus, tumor, or other obstruction can lead to ischemic necrosis, which is a localized area of tissue death.
        • Infarct refers to the area of ischemic necrosis.
        • Hypoxemia is a lack of oxygen, but blood flow is still present.
          • This can occur due to compressed breathing or Carbon Monoxide poisoning.
    • Epilepsy is a primary cause of CNS disease and is differentiated from seizures.
      • Epilepsy is idiopathic, irreversible, and lifelong.
      • Seizures are temporary events caused by abnormal electrical activity in the brain.
        • Causes can include trauma, drugs, and acid-base disorders.
    • Space Occupying Lesions (SOL) can also cause seizures.
      • Any increase in intracranial pressure can lead to seizures.
    • Secondary CNS disease is most commonly caused by circulatory problems.
      • Thrombosis within the heart can lead to blockage of the common carotid artery and the internal carotid artery, which can cause a stroke.
    • Cardiac disease can also cause secondary CNS disease.
      • A myocardial infarction can lead to impaired blood flow to the brain, resulting in hypoxemia.
    • Metabolic factors can contribute to secondary CNS disease.
      • Liver and kidney diseases can cause metabolic imbalances and contribute to brain dysfunction.
    • Chemical factors can cause secondary CNS disease.
      • Drugs, acid-base disorders, and fluid disorders can all lead to brain dysfunction.
        • Disruptions in osmolarity can lead to swelling in the brain.

    Manifestations of CNS Disease

    • Cerebral edema with increased intracranial pressure (ICP)
      • Hematoma: A collection of blood that pools
      • Infarction: Ischemic necrosis (tissue death due to lack of oxygen)
      • Pseudotumor cerebri: Increased ICP without an actual tumor
        • Commonly seen in children with "hypervitaminosis A" (excessive vitamin A intake)
      • Clinical effects:
        • Headaches:
          • Typical headaches: Slow progression, associated with pain
          • Headaches due to increased ICP: Sudden onset, associated with vomiting (not nausea), pulsatile, more common in the morning, "explosive" headache
            • Vomit due to stimulation of the chemoreceptor trigger zone in the medulla oblongata
        • Papilledema: Blurred margins of the optic disc due to swelling
          • Acute papilledema can lead to necrosis and chronic optic atrophy (swelling and loss of margins -> atrophy)
      • Three cardinal signs of ICP: Explosive headaches, projectile vomiting without nausea, papilledema

    Brain Herniations

    • Brain herniations: Occur when increased ICP causes pressure at sites where blood vessels and cranial nerves exit (e.g., foramen magnum)
      • Subfalcine:
        • The cingulate gyrus herniates into the falx cerebri (a fold of dura mater that separates the cerebral hemispheres)
        • Anterior cerebral arteries cross the falx cerebri
        • If herniation is on the right side, it can compress structures on the left side of the cingulate gyrus.
          • Clinical effects: Problems in the opposite extremity (e.g., right leg problems due to compression of the left cingulate gyrus)
      • Transtentorial:
        • The tentorium cerebelli separates the cerebrum from the cerebellum
        • Uncinate process (inferomedial portion of the cerebrum) can herniate through the tentorium cerebelli
        • The oculomotor nerve (CN III) passes through this area and can be compressed.
          • Clinical effects: Ipsilateral (same side) eye dilation and inability to move the eye properly (e.g., right uncinate herniation leads to right eye dilation)
      • Tonsillar:
        • Cerebellar tonsils (inferomedial aspect of the cerebellum) herniate through the foramen magnum, compressing the medulla oblongata.
          • The medulla controls heart and breathing.
          • Clinical effects: Respiratory and cardiac arrest
      • Duret hemorrhage (pontine hemorrhage):
        • Bleeding in the pons due to rupture of the pontine branches of the basilar artery.
        • Clinical effects: Locked-in syndrome (patient can see and hear but cannot communicate)

    Manifestations of CNS Disease

    • Cerebral edema with increased intracranial pressure (ICP) can be caused by a hematoma, infarction, or pseudotumor cerebri.
      • Hematoma: Collection of blood that pools.
      • Infarction: Ischemic necrosis.
      • Pseudotumor cerebri: A condition where increased ICP exists, but there is NO tumor present.
        • Most common in children and may be associated with hypervitaminosis A.
    • Clinical effects of increased ICP:
      • Headaches:
        • Increased ICP headaches occur suddenly, are often associated with vomiting (not nausea), and are pulsatile, being more severe in the morning.
        • Vomiting in cases of increased ICP is caused by the chemoreceptor trigger zone in the medulla oblongata.
      • Papilledema: Blurring of the optic disc margins due to swelling.
        • Acute papilledema can lead to necrosis and chronic optic atrophy.
      • 3 Cardinal signs of ICP: Exploding headaches, projectile vomiting without nausea, and papilledema.

    Brain Herniations

    • Brain herniations occur when an increase in ICP pushes brain tissue through openings in the skull. They can compress blood vessels and cranial nerves.
      • Subfalcine Herniation: The cingulate gyrus is pushed into the falx cerebri of the longitudinal fissure.
        • This can compress the anterior cerebral arteries.
        • If the herniation is on the right side, it can compress the left cingulate gyrus.
        • Clinical affects: Opposite limb problems (eg., right leg problems with a left-sided herniation).
      • Transtentorial Herniation: The unicate process herniates through the tentorium cerebelli, compressing the oculomotor nerve (CN III).
        • Clinical affects: Ipsilateral eye dilation and an inability to move the eye properly.
      • Tonsillar Herniation: The cerebellar tonsils herniate through the foramen magnum, compressing the medulla oblongata.
        • Clinical affects: Respiratory and cardiac dysfunction.
      • Duret Hemorrhage: Bleeding within the pons due to rupture of the pontine branches of the basilar artery.
        • Clinical affects: Locked-in syndrome, where the patient can see and hear but is unable to communicate.

    Global Brain Injury of CNS

    • Levels of consciousness: Alert, lethargy, stuporous, comatose.
    • Disorientation: Can be oriented to time, place, and person.
      • Most common causes of disorientation: Acid-base imbalance, drugs, insulin problems.
    • Lethargy: Person is conscious and aware but mentally tired, exhibiting drowsiness and indifference.
    • Stupor: Partially or nearly unconscious.
      • Requires continuous stimulation to remain awake, otherwise will fall into a coma.
    • Coma: State of unconsciousness where nothing will wake the patient.
      • Painful stimuli do not elicit a response.
    • Delirium vs. Dementia: Similar presentations but different causes.
      • Delirium: Reversible mental disturbance of short duration, usually due to a toxic state.
        • Characterized by hallucinations and incoherence.
        • Can be caused by metabolic syndromes.
      • Dementia: Irreversible state of psychosis.

    Hydrocephalus

    • Definition: Abnormal dilation of the brain ventricles due to excess accumulation of cerebrospinal fluid (CSF).
    • Choroid plexus: Located in the floor of the lateral ventricles and roof of the third and fourth ventricles. It is responsible for CSF production.
    • Non-communicating hydrocephalus: Complete obstruction within the ventricular system (CSF trapped within the ventricles).
      • Congenital causes:
        • Most common cause: Aqueduct of Sylvius stenosis (connects the third to the fourth ventricle).
        • Constriction of the aqueduct of Sylvius causes accumulation of CSF in the third and lateral ventricles.
        • Leads to enlargement of lateral ventricles, and subsequently, an enlarged head (if skull sutures are not yet fused).
    • Communicating hydrocephalus: Failure of reabsorption of CSF. More common than non-communicating hydrocephalus.
      • Acquired causes:
        • Meningitis: Accumulation of white blood cells in CSF can block reabsorption.

    Manifestations of Global Brain Injury

    • Levels of Consciousness:
      • Alert: Fully awake and responsive.
      • Lethargy: Drowsy, but can be aroused with minimal stimulation.
      • Stuporous: Difficult to arouse, requires vigorous stimulation.
      • Comatose: Unconscious, unresponsive to any stimuli.
    • Disorientation:
      • Time, Place, Person: Ability to recognize and orient oneself to these factors.
      • Most Common Causes: Acid-base imbalances, drug intoxication, insulin problems.
    • Lethargy: Patient is conscious and aware but exhibits mental fatigue, drowsiness, and indifference.
    • Stupor: Partial or near unconsciousness.
      • Requires significant stimulation to maintain wakefulness.
      • Progresses to coma without adequate stimulation.
    • Coma: State of profound unconsciousness.
      • Unresponsive to any stimuli, including painful ones.
    • Delirium vs. Dementia:
      • Delirium: A reversible state of mental disturbance with a short duration.
        • Often caused by a toxic state.
        • Characterized by hallucinations and incoherent speech.
        • Can be linked to metabolic syndromes.
      • Dementia: An irreversible state of psychosis.

    Hydrocephalus

    • Definition: Abnormal dilation of the brain's ventricles due to excessive accumulation of Cerebrospinal Fluid (CSF).
    • Choroid Plexus: Produces CSF and is located in the floor of the lateral ventricles and the roof of the 3rd and 4th ventricles.
    • Non-Communicating Hydrocephalus:
      • Complete obstruction within the ventricular system, trapping CSF within the ventricles.
      • Congenital Causes:
        • Most common cause: Aqueduct of Sylvius (connects the 3rd and 4th ventricles)
        • Constriction of the Aqueduct of Sylvius leads to CSF buildup in the 3rd and lateral ventricles.
        • Enlarged lateral ventricles result in head enlargement, especially in infants due to unclosed suture lines.
    • Communicating Hydrocephalus: More common than non-communicating.
      • Not a complete blockage, but a failure of CSF reabsorption by the arachnoid granulations.
      • Acquired Causes:
        • Infections like meningitis can lead to WBC accumulation in CSF, hindering reabsorption.

    Congenital Malformations

    • Neural Tube Defects:
      • Spina Bifida: Incomplete closure of the neural tube during fetal development.
        • Spina Bifida Occulta: Minor form, missing vertebral arch.
          • Most common in lumbar region.
          • Often asymptomatic.
          • May have a tuft of hair or mole in the lumbar region.
        • Meningocele: Protrusion of meninges through the defect.
          • Contains cerebrospinal fluid (CSF) and spinal nerves.
          • Spinal cord remains within the spinal canal.
        • Myelomeningocele: Most serious form.
          • Protrusion of meninges and spinal cord through the defect.
          • Can cause paralysis below the level of the defect.
          • Associated with Arnold-Chiari malformation.
      • Anencephaly: Absence of the cerebral hemispheres.
        • The brain stem is present, but the child's brain is incomplete.
        • Most infants are stillborn or die within days.
        • May have "frog-eyes" and low-set ears.
      • Cerebral Palsy: A non-progressive disorder affecting motor function.
        • Occurs at birth or shortly after.
        • Caused by damage to the brain.
        • Often related to problems during labor or delivery, such as cord compression.
        • Can also be caused by premature birth or other complications.
        • Spastic Diplegia: Often associated with premature birth or long, difficult labor.
        • May present with flexure syndrome in the legs or quadraplegia.
        • Infantile Hemiplegia: Stroke during delivery.
          • Affects one side of the body (ex: flexure contractions).
        • Arnold-Chiari Malformation: Cerebellar tonsils herniate into the spinal canal due to a small foramen magnum.
          • Often presents with headaches that are unresponsive to medications.
          • Can be treated surgically by widening the foramen magnum.

    Chromosomal Abnormalities

    • Mental Retardation Levels:
      • Profound IQ:

    Congenital Malformations

    • Neural Tube Defects: Result from the incomplete closure of the neural tube during embryonic development
      • Spina Bifida:
        • Spina Bifida Occulta: Most common type. Characterized by a small gap in the vertebral arch, usually in the lumbar region. Often asymptomatic and may not be discovered until later in life.
        • Meningocele: Protrusion of the meninges through the vertebral defect, forming a sac containing cerebrospinal fluid (CSF) and spinal nerves. The spinal cord itself remains within the spinal canal.
        • Myelomeningocele: The most severe form. The sac contains meninges, CSF, and part of the spinal cord. The spinal cord can be damaged, often leading to paralysis below the level of the defect. May be associated with Arnold Chiari malformation.
      • Anencephaly: Absence of the cerebral hemispheres, but the brainstem remains intact. Typically lethal, with most babies stillborn or dying within days.
        • May present with "frog-eyes" and low-set ears.
    • Cerebral Palsy: Non-progressive motor disorder caused by damage to the developing brain. This can occur before, during, or shortly after birth.
      • The cerebellum is most commonly affected.
      • Spastic Diplegia: Characterized by increased muscle tone and stiffness, primarily affecting the legs.
        • Premature: Often associated with premature birth and complications in the NICU.
        • Full-Term: Often associated with a prolonged and difficult labor resulting in oxygen deprivation (hypoxia) to the baby.
      • Infantile Hemiplegia: Affects one side of the body due to a stroke occurring during delivery.
      • Arnold Chiari Malformation: Condition where the cerebellum and brainstem herniate through the foramen magnum (opening at the base of the skull) due to a small posterior fossa, causing headaches. Can be relieved with surgery to enlarge the foramen magnum.
    • Chromosomal Abnormalities: Extra or missing chromosomes or changes in their structure can lead to a range of developmental disorders.
      • Mental Retardation: A broad term covering a range of intellectual impairments:

    Mental Retardation

    • Profound IQ: Scores below 20 on an IQ test

    Congenital Malformations

    • Neural Tube Defects
      • Spina Bifida
        • Spina Bifida Occulta: Most minor, posterior vertebral arch missing, common in lumbar region, usually no neurological issues.
        • Meningocele: Protrusion of meninges through defect, containing CSF and spinal nerves, but spinal cord intact.
        • Myelomeningocele: Meningocele with part of spinal cord within the sac. Most severe case, often leads to paralysis below injury level, wheelchair dependence. Can be associated with Arnold Chiari Syndrome.
      • Anencephaly: Absence of cerebral hemispheres, brain stem remains. Child may survive briefly but most are stillborn or die within days. Can present with "frog-eyes" and low-set ears.

    Cerebral Palsy

    • Non-progressive motor pathology acquired at birth or shortly after.
    • Causes:
      • Oxygen deprivation during labor or delivery (umbilical cord compression).
      • Hypoxia damage is permanent and doesn't worsen.
    • Types:
      • Spastic Diplegia:
        • Premature: May develop in NICU due to varying needs and complexities of premature care. Signs include flexure syndrome when walking, worst case: lower-extremity paraplegia.
        • Full-Term: Prolonged, difficult labor leading to severe hypoxia. Signs include quadriplegia and severe mental retardation in worst cases.
      • Infantile Hemiplegia: Stroke during delivery. Signs include flexure contractions and issues affecting one side of the body.
      • Arnold Chiari Syndrome: Flat, shallow occipital fossa causing herniation of cerebellar tonsils due to limited space. Signs include persistent headaches unresponsive to medication. Can be treated surgically by widening the foramen magnum.

    Chromosomal Abnormalities

    • Mental Retardation Levels:
      • Profound IQ: ... (Text is incomplete)

    Cerebrovascular Diseases

    • Cerebrovascular Accidents (CVA), or Strokes
      • Ischemic/Infarct
        • A blockage of blood flow causes hypoxia, which leads to necrosis and loss of function on one side of the body
        • Global strokes affect an entire section of the brain, examples include carbon monoxide poisoning and drowning
          • Watershed Infarct: Parasagittal location of the brain receives blood from two branches. If one is blocked, the other branch still supplies blood, but there may not be enough to meet the needs of that section.
          • Laminar Infarct: Penetrating arteries branch from outer arteries that cover the brain's surface. If blocked, layers/sections of gray matter can become necrotic.
          • Cells most at risk for hypoxia:
            • Pyramidal cells of the Sommer sector of the hippocampus
            • Purkinje cells of the cerebellum
        • Regional strokes affect a section of the brain, examples include a thrombus formed at the site of the brain or a thromboembolism that forms elsewhere and travels to the brain
          • Thromboembolism is the most common type of stroke.
      • Hemorrhagic
        • A vessel in the Circle of Willis forms an aneurysm and ruptures within the subarachnoid space (most common) or intracerebral tissue
        • Hemorrhage after a spinal tap indicates rupture into the cerebrospinal fluid.
        • Almost always, the patient will lose consciousness with only a 10-15% chance of survival.
    • Aneurysms
      • Congenital Berry Aneurysms
        • Weakness in the walls of the Circle of Willis, which worsens with age, forming aneurysms
        • Spontaneous, not due to trauma, can rupture forming a hemorrhagic stroke within the subarachnoid space
        • Most common location for a single Berry aneurysm is at the anterior cerebral artery with the anterior communicating artery
        • Most common location for multiple aneurysms is at the middle cerebral artery
      • Micro-Charcot-Bouchard (intracerebral hemorrhagic)
        • History of hypertension, aneurysms in gray matter, most common where the parietal lobe meets the occipital lobe
      • Atherosclerotic
        • Most susceptible are larger vessels like the Circle of Willis and their branches
    • Arteriovenous Malformations
      • Congenital type
      • Arterioles drain directly into venules without capillaries between them. This causes venules to dilate and rupture.

    Cerebrovascular Diseases

    • Cerebrovascular accident (CVA) or Stroke
      • Ischemic/Infarct
        • Blockage of blood flow causes hypoxia, leading to necrosis, resulting in loss of function on one side of the body
        • Global: Affects an entire section of the brain, often caused by carbon monoxide poisoning or drowning
        • Watershed infarct: Occurs in the parasagittal location of the brain where two blood vessel branches meet. If one branch is blocked, the remaining branch may not provide enough blood flow, leading to hypoxia.
        • Laminar infarct: Penetrating arteries that branch from outer arteries covering the brain surface can become blocked, causing necrosis in layers or sections of the gray matter.
        • High-risk cells for hypoxia:
          • Pyramidal cells in the Sommer sector of the hippocampus
          • Purkinje cells in the cerebellum
        • Regional: Affects a section of the brain, often caused by a thrombus (blood clot) formed at the site of the brain or a thromboembolism (blood clot that forms elsewhere and travels to the brain).
        • Thromboembolism is the most common type of stroke.
      • Hemorrhagic
        • Occurs when a vessel in the Circle of Willis forms an aneurysm and ruptures within the subarachnoid space (most common) or intracerebral tissue.
        • A spinal tap may reveal blood, indicating a rupture into the cerebrospinal fluid (CSF).
        • Hemorrhagic stroke almost always leads to loss of consciousness. There's only a 10-15% chance of survival.

    Aneurysms

    • Congenital Berry aneurysms
      • Weakness in the walls of the Circle of Willis develops and aneurysms form later with age.
      • These aneurysms are spontaneous (not caused by trauma) and can rupture, causing a hemorrhagic stroke within the subarachnoid space.
      • The anterior cerebral artery with the anterior communicating artery is the most common site for a single Berry aneurysm.
      • The middle cerebral artery is the most common site for multiple aneurysms.
    • Micro-Charcot-Bouchard aneurysms (intracerebral hemorrhagic)
      • Associated with a history of hypertension.
      • Aneurysms form within the gray matter.
      • The parietal-occipital lobe junction is the most common location.
    • Atherosclerotic aneurysms
      • Most common in larger blood vessels like the Circle of Willis and its branches.

    Arteriovenous Malformations

    • Congenital
      • Small arterioles drain directly into venules without capillaries between them.
      • This can cause venule dilation and rupture.

    CNS Trauma

    • Blunt Force Trauma: Involves trauma to the brain without skull penetration.

      • Concussion: Transient loss of consciousness or awareness.

        • Retrograde amnesia: Inability to recall events after the trauma.
        • Anterograde amnesia: Inability to recall events prior to the trauma.
        • Disruption of ascending reticular formation: Although there is no evident organic brain damage, this structure is disrupted.
        • Chronic Traumatic Encephalopathy (CTE): Brain tissue resembles that of Alzheimer's disease.

      • Epidural Hematoma: Accumulation of blood between the dura mater and skull.

        • Rupture of middle meningeal artery: This occurs around the temporal region of the brain/skull.

      • Subdural Hematoma: Venous bleeding.

        • Rupture of bridging veins: These veins drain from the brain surface into dural venous sinuses.
        • Shaken Baby Syndrome and Nursing Home Syndrome: These are examples of conditions where subdural hematomas occur.
        • Chronic Subdural hematomas: More common than acute types.

      • Contusion: Bruising of the brain.

        • Petechiae: Pinpoint hemorrhages, small (1 cm)
        • Purpura: Larger hemorrhages, 1 cm or greater
        • Coup Contusion: Bruising on the brain surface directly under the point of skull impact.
        • Contrecoup Contusion: Injury to the occipital lobe due to a frontal injury, caused by brain rebound.
          • Occipital injury: The brain moves anteriorly, potentially scraping against the ethmoid cribriform plate, leading to significant bleeding.

    • Penetrating Trauma: Involves penetration of the skull.

      • High-Velocity Trauma: Entry and exit wounds with minimal or no bleeding.

        • Rapid increase in intracranial pressure (ICP) and hemorrhaging due to rapid gas expansion, leading to immediate death.

      • Low-Velocity Trauma: Entry wound, with or without an exit wound.

        • Bleeding and edema along the bullet's path: Leading to a slower increase in ICP.

    Spinal Cord Injury

    • Hyperextension: Head thrown backward.

      • Posterior contusion of the spinal cord: Impacts the dorsal columns.
      • Ruptured anterior longitudinal ligament (ALL).

    • Hyperflexion: Head thrown forward.

      • Anterior contusion of the spinal cord.
      • Teardrop fracture of the anterior part of the vertebrae:

    • Hemisection of the Cord (Brown-Sequard Syndrome):

      • Ipsilateral paralysis and loss of fine touch, vibration, and position sense: Occurs on the same side of the injury.
      • Contralateral loss of pain and temperature: Occurs on the opposite side of the injury.

    CNS Trauma

    • Blunt force trauma

      • Concussion:
        • Transient loss of consciousness or actual loss of consciousness.
        • Retrograde amnesia: Inability to recall events leading up to the trauma.
        • Anterograde amnesia: Inability to recall events following the trauma.
        • No visible brain damage, but disruption to the ascending reticular formation.
        • CTE (chronic traumatic encephalopathy): Brain tissue degeneration similar to Alzheimer's.
      • Epidural hematoma:
        • Accumulation of blood between the dura mater and skull.
        • Caused by rupture of the middle meningeal artery in the temporal region.
      • Subdural hematoma:
        • Venous bleeding caused by ruptured bridging veins that drain into dural venous sinuses.
        • Often associated with shaken baby syndrome or nursing home syndrome.
        • Chronic subdural hematomas are more common than acute.
      • Contusion:
        • Bruising of the brain.
        • Types:
          • Coup: Bruising directly beneath the area of the skull impact.
          • Contrecoup: Bruising in opposite area (e.g., occipital lobe injury due to frontal impact). Occipital injury can cause bleeding by scraping against the ethmoid cribriform plate.

    • Penetrating Trauma

      • High velocity:
        • Entry and exit wounds, with limited bleeding.
        • Rapid increase in intracranial pressure (ICP) and hemorrhaging caused by expanding gases from the bullet.
        • Often results in immediate death.
      • Low velocity:
        • Entry wound with or without an exit wound.
        • Causes bleeding and edema along bullet's path.
        • Gradual increase in intracranial pressure.

    • Spinal Cord Injury

      • Hyperextension:
        • Occurs with head thrown backward.
        • Results in posterior contusion of the spinal cord affecting dorsal columns, and rupture of the anterior longitudinal ligament (ALL).
      • Hyperflexion:
        • Occurs with head thrown forward.
        • Results in anterior contusion of the spinal cord and a teardrop fracture of the anterior vertebra.
      • Hemisection of the cord (Brown-Sequard syndrome):
        • Ipsilateral paralysis and loss of fine touch, vibration, and position sense.
        • Contralateral loss of pain and temperature sensation.

    CNS Infections: Route of Entry

    • CNS infections can enter through the bloodstream (hematogenous), directly from local infections (sinusitis, otitis media), or penetrating injuries (fractures leading to rhinorrhea or otorrhea).

    Meningitis

    • Meningitis is an infection within the subarachnoid space.
    • Bacterial Meningitis:
      • Requires immediate treatment and can lead to sepsis and disseminated intravascular coagulation (DIC).
      • DIC can cause death due to bilateral adrenal hemorrhage (Waterhouse-Friderichsen syndrome).
      • Neisseria meningitidis is the most serious type, causing meningococcal meningitis.
    • Viral Meningitis:
      • Often resolves on its own and is similar to a cold.
      • Common causes include Coxsackievirus, mumps, and Epstein-Barr virus (EBV).
    • Acute Bacterial/Suppurative Meningitis:
      • Characterized by an increase in neutrophils, leading to elevated pus cells.
      • Affects the leptomeninges in the subarachnoid space.
      • Signs and symptoms include:
        • Increased protein and decreased glucose levels in cerebrospinal fluid (CSF).
        • Cloudy CSF due to pus cells.
        • Stiff neck, fever, and headache.
        • Brudzinski's sign (flexing the head causes the knees to flex).
        • Kernig's sign (extending the leg, knee, and foot pulls on the meninges, causing pain).
    • Acute Viral Meningitis:
      • Marked by an increase in lymphocytes.
    • Chronic Meningitis:
      • Often caused by tuberculosis or Mycobacterium.
      • Tuberculosis can lead to caseous granulomatous meningitis.

    Neurosyphilis

    • Tertiary syphilis caused by Treponema pallidum and diagnosed using the Venereal Disease Research Laboratory (VDRL) test.
    • Meningovascular Syphilis:
      • Occurs 3 years after infection and causes the meninges to fuse due to chronic inflammation.
      • Compresses cranial nerves traversing the subarachnoid space.
    • Parenchymal Syphilis:
      • Develops 10 years after infection and causes:
        • General paresis (progressive dementia and psychosis with cerebral atrophy).
        • Tabes dorsalis (loss of sensation in the feet, leading to a slapping gait).

    Viral Encephalitis

    • A severe brain infection that can lead to death and permanent neurological damage.
    • Pathology:
      • Perivascular cuffing: Accumulation of lymphocytes around blood vessels in the gray matter.
      • Neuronophagia: Destruction of neurons by the virus.
      • Reactive gliosis: Accumulation of astrocytes at the site of injury, similar to scar formation.
    • Inclusion bodies: Viral particles within cells.

    CNS Infections

    • Infections can enter the CNS via hematogenous spread (bacteremia, viremia), direct infection (e.g., sinusitis, otitis media), or penetrating injuries (e.g., skull fractures).

    ### Meningitis

    • Infection of the subarachnoid space.

    ### Bacterial Meningitis

    • Requires immediate treatment and can lead to sepsis and disseminated intravascular coagulation (DIC), potentially causing Waterhouse-Friderichsen syndrome (bilateral adrenal hemorrhage).
    • Neisseria meningitidis is the most serious type, causing meningococcal meningitis.

    ### Viral Meningitis

    • Resembles a cold and usually resolves on its own.
    • Common causes include Coxsackievirus, mumps, and Epstein-Barr virus.

    ### Acute Bacterial/Suppurative Meningitis

    • Characterized by neutrophils attacking the meninges, leading to increased pus cells (suppuration).
    • Involves the leptomeninges in the subarachnoid space.
    • Signs include increased protein and decreased glucose in cerebrospinal fluid (CSF), cloudy CSF due to pus cells, stiff neck, fever, and headache.
      • Brudzinski's sign: Flexing the head causes reflexive knee flexion.
      • Kernig's sign: Extending the leg, knee, and foot stretches the meninges, causing pain.

    Acute Viral Meningitis

    • Characterized by lymphocytes attacking the meninges.

    ### Chronic Meningitis

    • Caused by organisms like Mycobacterium tuberculosis.
    • Tuberculosis can cause caseous granulomatous meningitis.

    ### Neurosyphilis (Tertiary Syphilis)

    • Caused by Treponema pallidum and diagnosed with the VDRL test.

    Meningovascular Syphilis

    • Occurs approximately 3 years after infection and involves fusion of the meninges due to chronic inflammation.
    • Compresses cranial nerves passing through the subarachnoid space.

    Parenchymal Syphilis

    • Occurs approximately 10 years after infection and can lead to:
      • General paresis: Progressive dementia and psychosis with cerebral atrophy.
      • Tabes dorsalis: Loss of sensation in the feet, resulting in a characteristic "slapping gait."

    ### Viral Encephalitis

    • A severe infection of the brain that can lead to death and permanent neurological damage.
    • Pathological features:
      • Perivascular cuffing: Accumulation of lymphocytes in and around blood vessels in the gray matter.
      • Neuronophagia: Virus-mediated destruction of neurons.
      • Reactive gliosis: Astrocyte response to injury, analogous to scar formation.
      • Inclusion bodies: Abnormal structures within cells, often indicative of viral infection.

    Sporadic Viral Infections

    • Herpes Simplex Encephalitis
      • HSV-1 commonly affects adults, while HSV-2 affects neonates.
      • Causes hemorrhagic necrotizing encephalitis in the temporal lobes and orbital frontal areas.
      • Characterized by intranuclear inclusion bodies called Cowdry bodies.
    • Cytomegalovirus
      • Infection is prevalent in neonates.
      • Primarily affects the ependyma.
      • Causes perivascular cuffing, glial nodules, and enlarged neurons.
    • Subacute Sclerosing Panencephalitis (SSPE)
      • Caused by the measles virus (rubeola).
      • Commonly affects children under 7 years old, leading to slow progressive dementia.
      • Dementia can manifest years after infection, with an 80% mortality rate.
      • Causes neuronal degeneration in the frontal lobe and basal ganglia.

    Epidemic Viral Infections

    • Arbovirus Infections
      • West Nile Encephalitis:
        • Transmitted by mosquitoes.
        • A Flaviviridae virus that can cause jaundice.
    • HIV Encephalitis
      • Causes perivascular cuffing, glial nodules, and multinucleated giant cells.
      • Primarily affects the white matter and basal ganglia.

    Acquired Diseases

    • Poliomyelitis
      • Transmitted through the fecal-oral route.
      • Causes acute lymphocytic meningitis and nonparalytic meningitis.
      • 2% of infected individuals experience lower motor paralysis without sensory loss.
      • Characterized by anterior horn asymmetric paralysis with loss of deep tendon reflexes.
      • Can lead to paralysis of respiratory muscles, requiring assisted ventilation.
    • Rabies
      • Often carried by skunks.
      • Causes phalangeal paralysis, leading to difficulty swallowing and increased salivation.
      • Characterized by necrotizing encephalitis affecting the brainstem, basal ganglia, hippocampus, and Purkinje cells of the cerebellum.
      • Diagnosed by the presence of eosinophilic cytoplasmic inclusion bodies called Negri bodies.
      • Once symptoms appear, there is no treatment, and mortality occurs within a week.

    Prion Encephalopathies

    • Proteinaceous infectious particles
    • Spongiform encephalopathies:
      • Caused by the formation of microcysts in the gray matter of the brain.
    • Lack of RNA or DNA, solely an infectious protein.
    • Other names:
      • Scrapie (sheep)
      • Mad Cow Disease (cattle)
    • Major types:
      • Creutzfeldt-Jakob Disease
      • Kuru:
        • Associated with cannibalism.
        • Characterized by uncontrollable laughter.
    • Causes:
      • Transmissible dementia followed by ataxia.

    Parasitic Infections

    • Toxoplasmosis
      • Can be transmitted during the third trimester through feline feces.
      • The parasite becomes airborne after two days in the litter.
    • Primary Amoebic Meningoencephalopathy
      • Naegleria Fowleri:
        • Found in contaminated freshwater sources.
        • Migrates up the nasal cavity, burrows through the cribriform plate, and feeds on the frontal lobe.
      • 100% fatal.

    Sporadic Viral Infections

    • Herpes Simplex Encephalitis:

      • HSV-1 primarily affects adults, while HSV-2 most commonly affects neonates.
      • Causes hemorrhagic necrotizing encephalitis in the temporal lobes and orbital frontal areas.
      • Characterized by intranuclear inclusion bodies known as Cowdry bodies.

    • Cytomegalovirus:

      • Common infection in neonates.
      • Primarily affects the ependyma.
      • Results in perivascular cuffing, glial nodules, and enlarged neurons.

    • Subacute Sclerosing Panencephalitis:

      • Caused by the rubeola (red measles) virus.
      • Typically affects children under 7 years old.
      • Leads to slow progressive dementia, often manifesting years after infection.
      • High mortality rate (80%).
      • Causes degeneration of neurons in the frontal lobe and basal ganglia.

    Epidemic Viral Infections

    • Arbovirus Infections:

      • West Nile Encephalitis:
        • Transmitted through mosquitoes.
        • Classified as a Flaviviridae, causing jaundice.

    • HIV Encephalitis:

      • Leads to perivascular cuffing, glial nodules, and multinucleated giant cells.
      • Primarily affects the white matter and basal ganglia.

    Acquired Diseases

    • Poliomyelitis:

      • Transmitted via fecal-oral route.
      • Causes acute lymphocytic meningitis and nonparalytic meningitis.
      • In a small percentage (2%) of infected individuals, it results in lower motor paralysis without sensory loss.
        • Marked by anterior horn asymmetric paralysis and loss of deep tendon reflexes.
      • Can paralyze respiratory muscles, requiring assisted ventilation.

    • Rabies:

      • Skunks are a common carrier.
      • Causes:
        • Phalangeal paralysis, hindering swallowing and leading to increased salivation.
        • Necrotizing encephalitis affecting the brainstem, basal ganglia, hippocampus, and Purkinje cells of the cerebellum.
      • Characterized by eosinophilic cytoplasmic inclusion bodies called Negri bodies.
      • No treatment is available once symptoms develop, and mortality occurs within a week.

    • Prion Encephalopathies:

      • Caused by proteinaceous infectious particles (prions).
      • Known as spongiform encephalopathies due to the microcysts they create in the brain's gray matter.
      • Lack RNA or DNA, consisting solely of an infectious protein.
      • Other names:
        • Scrapie in sheep.
        • Mad cow disease in cows.
      • Major types:
        • Creutzfeldt-Jakob Disease.
        • Kuru:
          • Associated with cannibalism and can cause uncontrollable laughter.
      • Causes:
        • Transmissible dementia followed by Ataxia.

    Parasitic Infections

    • Toxoplasmosis:

      • Transmitted through feline feces, particularly during the third trimester of pregnancy.
      • The parasite can become airborne after 2 days of being in the litter.

    • Primary Amoebic Meningoencephalopathy:

      • Caused by Naegleria fowleri, an amoeba found in contaminated freshwater sources.
      • Migrates through the nasal cavity, penetrates the cribriform plate, and infects the frontal lobe.
      • 100% fatal.

    Demyelinating Diseases

    • Demyelinating diseases involve the white matter of the central nervous system (CNS).
    • They can be congenital or acquired.

    Congenital Demyelinating Diseases (Leukodystrophies)

    • These diseases are genetic, intrinsic disorders that affect the generation or maintenance of myelin.
    • The disorders progress relentlessly, are widespread and symmetrical.

    Metachromatic Leukodystrophy

    • A lysosomal disorder that results from a lack of enzymes necessary to break down cerebroside.
    • Most common in infants, leading to death within 5-10 years.
    • Causes a loss of special senses, pain, motor function, memory, and cognitive skills.

    Adrenoleukodystrophy

    • Most common form is X-linked recessive.
    • Characterized by the presence and production of very long chain (VLC) fatty acids, primarily in the adrenal glands.
    • This leads to adrenal insufficiency.

    Acquired Demyelinating Diseases

    • Acquired demyelinating diseases are not present at birth but develop later in life.

    Multiple Sclerosis (MS)

    • The most common acquired demyelinating disease of the CNS.
    • Most commonly affects Scandinavians.
    Etiology of MS
    • T-cell mediated type IV hypersensitivity.
    • Both CD4 and CD8 cells are involved.
    Causes of MS
    • Plaquing of demyelination, primarily in the periventricular region.
    • Oligodendrocytes are lost leading to proliferation of astrocytes and reactive gliosis.
    • Unilateral visual loss due to optic neuritis.
    • Neurological deficits followed by respiratory or renal complications, ultimately leading to death.

    Acute Disseminated Encephalomyelitis (ADEM)

    • Also known as post-infectious encephalomyelitis.
    • Monophasic demyelinating disease affecting the brain and spinal cord after an infection has been resolved.
    • Causes demyelination of white matter in the brain and spinal cord, with lymphocytic perivascular cuffing.
    • Key fact: Lymphocytic perivascular cuffing is associated with encephalopathy, not meningitis.
    • Caused by infections such as measles, chicken pox, and rubella.
    • Rubella infection is a significant risk factor for unborn children, potentially leading to deafness, mute-ness, and blindness.

    Sporadic Virus Infection

    • Progressive multifocal leukoencephalopathy (PML)
    • Caused by the JC virus of the papovaviral group.
    • Attacks oligodendrocytes, resulting in areas of demyelination.
    • Observed in immunocompromised patients, including those with AIDS.

    Pernicious Anemia

    • An autoimmune disorder characterized by chronic atrophic gastritis that destroys parietal cells in the stomach.
    • Parietal cells produce hydrochloric acid (HCl) and intrinsic factor.
    • Intrinsic factor assists in vitamin B12 absorption in the ileum.
    • Vitamin B12 is crucial for maintaining the integrity of folate (B9) and red blood cell maturation.
    • Results in megaloblastic macrocytic anemia.
    • Causes subacute combined degeneration of the spinal cord, leading to sensory and motor degeneration.

    Demyelinating Diseases

    • Involve the white matter
    • Occur either congenitally or acquired

    Congenital Demyelinating Diseases (Leukodystrophies)

    • Genetic, intrinsic disorder that affects myelin generation or maintenance
    • Progress relentlessly, is widespread and symmetrical

    Metachromatic Leukodystrophy

    • Lysosomal disorder with lack of enzymes to break down cerebroside
    • Most common in infants, leading to death within 5 to 10 years
    • Causes loss of special senses, pain, motor function, memory, and cognitive skills

    Adrenoleukodystrophy

    • Most common form is X-linked recessive
    • Production of very long chain (VLC) fatty acids, especially in the adrenal glands
      • Causes adrenal insufficiency

    Acquired Demyelinating Diseases

    • Multiple Sclerosis (MS)
      • Most common acquired demyelinating disease of the Central Nervous System (CNS)
      • Most commonly affects Scandinavians
      • T-cell mediated type IV hypersensitivity, with both CD4 and CD8 cells involved
      • Causes plaque formation, primarily in the periventricular region
        • Loss of oligodendrocytes followed by astrocyte proliferation, causing reactive gliosis
      • Causes unilateral visual loss due to optic neuritis
      • Progresses to neurological deficits, followed by respiratory or renal complications leading to death

    Acute Disseminated Encephalomyelitis (ADEM)

    • Monophasic demyelinating disease affecting the brain and spinal cord after an infection
    • Causes demyelination of white matter in the brain and spinal cord with lymphocytic perivascular cuffing
      • Lymphocytic perivascular cuffing is associated with encephalopathy, not meningitis
    • Caused by measles, chicken pox, and rubella infections
      • Rubella infection in unborn children is particularly dangerous, leading to deafness, muteness, and blindness

    Sporadic Viral Infection

    • Progressive Multifocal Leukoencephalopathy (PML)
      • Caused by the JC virus of the papovaviral group
      • Attacks oligodendrocytes causing areas of demyelination
      • Seen in immunocompromised patients and those with AIDS

    Pernicious Anemia

    • Chronic atrophic gastritis is an autoimmune disorder that destroys parietal cells in the stomach
      • Parietal cells produce hydrochloric acid (HCl) and intrinsic factor
        • Intrinsic factor aids in vitamin B12 absorption in the ileum
          • Vitamin B12 is necessary for maintaining the integrity of folate and maturing red blood cells
    • Causes megaloblastic macrocytic anemia
    • Leads to subacute combined degeneration of the spinal cord, causing sensory and motor degeneration

    Degenerative Diseases

    • Involve the gray matter
    • Alzheimer's disease:
      • Most common cause of dementia
      • Pathology:
        • Frontal lobe most commonly affected
        • Congophilic angiopathy in blood vessels leading to fibrinoid necrosis
        • Senile plaques of beta-amyloid
        • Granulovacuolar degeneration of pyramidal cells of the hippocampus
      • Signs:
        • Order of loss: Memory loss occurs first, followed by personality disorders, then lastly speech
    • Pick disease:
      • Aka Frontotemporal dementia/lobar sclerosis
      • Signs:
        • Order of loss: Personality changes occurs first, followed by speech, then lastly memory loss
      • Pathology:
        • Unilateral, normally affects dominant side of frontal and temporal lobes
    • Parkinson disease:
      • Aka idiopathic Parkinsonism
      • Pathology:
        • Degenerative disorder of dopamine secreting neurons in substantia nigra
        • Substantia Nigra, which is loss of pigment in pigmented neurons found in the midbrain
        • Contains an inclusion body called Lewy body
      • Signs:
        • Shuffling gate, stooped posture, mask-like face, resting tremor
    • Huntington's disease:
      • Overall depletion of GABA
        • GABA normally inhibits further excitation of alpha motor neurons
        • Depletion of GABA leads to a lowered excitatory threshold, meaning greater stimuli can occur
      • Signs:
        • Delusional thinking, paranoia, personality changes
        • Onset begins around late 30's, early 40's.
      • Atrophy of caudate nucleus leading to concavity of lateral wall of lateral ventricle
    • Spinocerebellar degeneration:
      • Aka Friedreich ataxia
      • Degeneration of multiple tracts of brainstem & spinal cord
      • Onset beings around adolescence
      • Signs & symptoms:
        • If in cerebellum, will show ataxia & intention tremor
        • If in brain stem, will show rigidity & tremor
        • If in spinal cord, will show decrease in deep tendon reflex & changes in vibratory senses
      • MC cause of death is hypertrophic cardiomyopathy, which is entire enlargement of the left ventricle & septum
    • Amyotrophic lateral sclerosis (ALS):
      • Progressive neurological degenerative disorder
      • Affects both upper & lower motor neuron tracts
        • Upper motor neuron tracts:
          • Goes from brain to spinal cord
          • Injury leads to spastic paralysis
        • Lower motor neuron tracts:
          • Goes from spinal cord to muscle cell
          • Injury leads to flaccid paralysis
      • Areas affected:
        • Anterior horn cells of spinal cord, motor nuclei of brain stem, upper motor neurons of cerebral cortex
        • Lateral corticospinal tracts are the most affected
        • Small muscles affected first, i.e. facial muscles, muscles involved in speech, hand muscles
        • Larger muscles involved later i.e. easily trips over self
      • Overview of pathology:
        • Progressive disorder
        • Brain is not affected, cognitive function is unaffected
        • Muscles do not atrophy, they just lose nerve controls

    Degenerative Diseases

    • Involve the gray matter of the brain.

    Alzheimer's Disease

    • The most common cause of dementia.
    • Pathology:
      • Frontal lobe is most commonly affected.
      • Congophilic angiopathy in blood vessels leads to fibrinoid necrosis.
      • Senile plaques of beta-amyloid.
      • Granulovacuolar degeneration of pyramidal cells of the hippocampus.
    • Signs:
      • Memory loss occurs first, followed by personality disorders, then lastly speech.

    Pick Disease

    • Also known as Frontotemporal dementia or lobar sclerosis.
    • Signs:
      • Personality changes occur first, followed by speech, then lastly memory loss.
    • Pathology:
      • Unilateral, normally affects the dominant side of the frontal and temporal lobes.

    Parkinson's Disease

    • Also known as idiopathic Parkinsonism.
    • Pathology:
      • Degenerative disorder of dopamine-secreting neurons in the substantia nigra.
      • Substantia nigra, which is the loss of pigment in pigmented neurons found in the midbrain.
      • Contains an inclusion body called a Lewy body.
    • Signs:
      • Shuffling gait, stooped posture, mask-like face, resting tremor.

    Huntington's Disease

    • Overall depletion of GABA.
      • GABA normally inhibits further excitation of alpha motor neurons.
      • Depletion of GABA leads to a lowered excitatory threshold, meaning greater stimuli can occur.
    • Signs include delusional thinking, paranoia, personality changes.
      • Onset begins around late 30s, early 40s.
    • Atrophy of the caudate nucleus leading to concavity of the lateral wall of the lateral ventricle.

    Spinocerebellar Degeneration

    • Also known as Friedreich ataxia.
    • Degeneration of multiple tracts of the brainstem & spinal cord.
    • Onset begins around adolescence.
    • Signs & symptoms:
      • If in the cerebellum, will show ataxia & intention tremor.
      • If in the brainstem, will show rigidity & tremor.
      • If in the spinal cord, will show a decrease in deep tendon reflex & changes in vibratory senses.
    • The most common cause of death is hypertrophic cardiomyopathy, which is the entire enlargement of the left ventricle & septum.

    Amyotrophic Lateral Sclerosis (ALS)

    • A progressive neurological degenerative disorder.
    • Affects both upper and lower motor neuron tracts:
      • Upper motor neuron tracts:
        • Goes from the brain to the spinal cord.
        • Injury leads to spastic paralysis.
      • Lower motor neuron tracts:
        • Goes from the spinal cord to the muscle cell.
        • Injury leads to flaccid paralysis.
    • Areas affected:
      • Anterior horn cells of the spinal cord.
      • Motor nuclei of the brainstem.
      • Upper motor neurons of the cerebral cortex.
      • Lateral corticospinal tracts are the most affected.
      • Small muscles affected first, i.e., facial muscles, muscles involved in speech, hand muscles.
      • Larger muscles involved later, i.e., easily trips over oneself.
    • Overview of pathology:
      • Progressive disorder.
      • Brain is not affected, cognitive function is unaffected.
      • Muscles do not atrophy, they just lose nerve control.

    Inherited Metabolic Disorders of Neurons

    • Phenylketonuria (PKU)

      • Lack of phenylalanine hydroxylase enzyme
      • Results in lack of tyrosine production leading to metabolic acidosis
      • Diagnosed through heel prick test in newborns
      • Management involves a phenylalanine-free diet
      • Most common form of avoidable mental retardation

    • Tay-Sachs disease

      • Lysosomal storage disease
      • Accumulation of glucocerebroside due to lack of enzyme breakdown
      • Characterized by prominent lysosomes in a whorl configuration and a cherry red spot on the macula
      • Onset around 6 months of age with rapid decline, leading to death within a few years

    • Niemann-Pick disease

      • Lysosomal storage disease
      • Sphingomyelin disorder
      • Leads to visceromegaly

    • Wilson disease

      • Excess copper accumulation due to ceruloplasmin deficiency (copper carrier protein)
      • Copper deposits in liver, lenticulate nucleus, and iris
      • Clinical manifestations:
        • Kayser-Fleischer rings (brownish copper tint surrounding iris)
        • Hepatolenticular degeneration

    Acquired Metabolic Disorders of Neurons

    • Wernicke-Korsakoff syndrome

      • Occurs in chronic alcoholics attempting to quit
      • Wernicke's encephalopathy
        • Brain stem lesion due to thiamin (vitamin B1) deficiency
        • Occurs during alcohol withdrawal
        • Manifestations:
          • Confusion, drowsiness, disorientation
          • Ataxia
          • Nystagmus of CN VI
          • Polyneuropathies leading to convulsions, coma, and death
          • Hemorrhaging in mammillary bodies
      • Korsakoff psychosis
        • Alcoholic amnesia disorder
        • Manifestations:
          • Retrograde amnesia
          • Anterograde amnesia
          • Loss of grooming skills (ADL's)
          • Apathy and indifference

    • Hepatic encephalopathy

      • Genetic disorder leading to high blood urea nitrogen (BUN) levels
      • Liver damage results in high ammonia accumulation in the blood
      • High ammonia levels in the brain can lead to coma

    • Subacute combined degeneration of the spinal cord

      • Deficiency in vitamin B12
      • Leads to decreased myelin in the spinal cord
      • Also causes pernicious anemia

    Inherited Metabolic Disorders of Neurons

    • Phenylketonuria (PKU)

      • Lack of enzyme phenylalanine hydroxylase leads to lack of tyrosine production and metabolic acidosis.
      • Diagnosed with a heel prick test in newborns.
      • Individuals with PKU are placed on a phenylalanine-free diet.
      • Most common form of avoidable mental retardation.

    • Tay-Sachs Disease

      • Lysosomal storage disease caused by an accumulation of glucocerebroside due to a lack of the enzyme to break it down.
      • Prominent lysosomes in a whorl configuration within the brain.
      • Cherry-red spot on the macula of the eye.
      • Infants begin declining around 6 months of age and typically only live a few years.

    • Niemann-Pick Disease

      • Lysosomal storage disease characterized by a sphingomyelin disorder.
      • Leads to visceromegaly.

    • Wilson Disease

      • Excess accumulation of copper in the body due to a deficiency in ceruloplasmin, a carrier protein for copper.
      • Copper accumulates in the liver, lenticulate nucleus, and iris of the eye.
      • Signs:
        • Kayser-Fleischer rings - a brownish copper tint surrounding the iris.
        • Hepatolenticular degeneration.

    Acquired Metabolic Disorders of Neurons

    • Wernicke-Korsakoff Syndrome

      • Commonly occurs in chronic alcoholics trying to quit.
      • Wernicke's Encephalopathy
        • Brain stem lesion due to a deficiency in vitamin B1 (thiamin).
        • Occurs when individuals are coming off alcohol and are dehydrated.
        • Signs & Symptoms:
          • Confusion, drowsiness, disorientation.
          • Ataxia.
          • Nystagmus of CN VI.
          • Multiple polyneuropathies leading to convulsions, coma, and death.
          • Hemorrhaging in the mammillary bodies.
      • Korsakoff Psychosis
        • Alcoholic amnesia disorder.
        • Signs & Symptoms:
          • Retrograde amnesia.
          • Anterograde amnesia.
          • Loss of grooming skills and activities of daily living (ADLs).
          • Apathy and indifference.

    • Hepatic Encephalopathy

      • Genetic disorder causing high levels of blood urea nitrogen (BUN) leading to liver damage.
      • High accumulation of ammonia in the blood, which, when circulating through the brain, can lead to coma.

    • Subacute Combined Degeneration of the Spinal Cord

      • Deficiency in vitamin B12 leads to a decrease in myelin in the spinal cord.
      • Vitamin B12 deficiency also leads to pernicious anemia.

    Nervous System Neoplasms

    • Most brain tumors are malignant and originate from neuroglial cells, like astrocytes, ependymal cells, and oligodendrocytes.
    • Most tumors of the CNS are metastatic, originating from other parts of the body.
    • Most CNS tumors in adults are supratentorial, while most infratentorial tumors are found in children.

    Gliomas

    • Metastatic tumors are the most common malignant tumors of the CNS.
    • Astrocytoma is the Most common primary neoplasm and type of glioma.
      • Derived from astrocytes.
      • Grade 1 is well-differentiated and not aggressive.
      • Slow growing, some respond to radiation.
    • Glioblastoma multiforme is a Grade 4 malignant astrocytoma.
      • Accounts for 1/3rd of all malignant gliomas in the CNS.
      • Most aggressive type.
      • Only tumor that can cross the midline, also known as the "butterfly tumor".
    • Juvenile pilocytic astrocytoma is derived from astrocytes.
      • Accounts for 1/4th of all brain tumors in children under 10 years old.
      • Highly operable with a good prognosis.
    • Oligodendroglioma is derived from oligodendrocytes.
      • Occurs most commonly in mid-life.
      • 5-10 year post-surgery survival rate.
      • Can see speckled calcifications on radiographs.
    • Ependymoma is derived from ependymal cells lining the ventricles of the brain.
      • When located in the brain, it will be found in the 4th ventricle.
    • Medulloblastoma originates in the cerebellum.
      • Primarily seen in children and young adults.
      • Accounts for 1/4th of all brain tumors in children.
      • Highly malignant and metastasizes through the CSF to the spinal cord.
    • Meningioma is a benign tumor that does not infiltrate other tissues.
      • Grows in the subdural space, within the inner aspect of the dura mater.
      • Causes compression of surrounding tissue.
      • More common in females due to progesterone receptors.
      • Contains layers of calcium and can form psammoma bodies.

    Lymphoma

    • Primary lymphoma to the brain is of B lymphocyte type.
    • Occurs in immunocompromised individuals, such as AIDS patients.

    Secondary Neoplasms

    • Metastasis to the brain is a common occurrence.
    • The most common type of brain metastasis is from lung cancer.
    • Order of most common metastasis:
      • Lung, breast, skin, kidneys, and finally GI tract.

    Craniopharyngioma

    • Most common in teens to early 20's.
    • Often contains cholesterol crystal calcifications.
    • Located superior to the sella turcica and can compress the hypothalamus, optic chiasma, and 3rd ventricle.

    Peripheral Nervous System Disorders

    • Guillain-Barre Syndrome is an acquired autoimmune condition following viral infections, causing ascending paralysis.
      • Begins with tingling and weakness in lower extremities.
    • Myasthenia Gravis is an autoimmune condition destroying neuromuscular junctions, causing descending paralysis.
      • Begins with facial muscles and eyes, causing ptosis and diplopia.
    • Neurofibromatosis
      • Type I Neurofibromatosis (von Recklinghausen disease):
        • Peripheral type.
        • Develops multiple benign skin tumors and peripheral nerve tumors.
        • Develops Café au lait spots, which are pigmented lesions on the skin.
      • Type II Neurofibromatosis:
        • Central type.
        • Bilateral acoustic neuromas of CN VIII (vestibulocochlear n.), which can lead to deafness.
        • Can cause compression of CN VII (facial n.) due to its proximity to CN XIII, leading to facial palsy.
    • Trigeminal Neuralgia (tic douloureux):
      • Affects all 3 branches of CN V (trigeminal n.).
      • Light touch to the face triggers pain responses.
      • Occurs usually later in life.
    • Facial Paralysis (Bell's Palsy):
      • Affects CN VII (facial n.) causing loss of function of facial muscles.
      • Eyes cannot close fully, requiring eye drops as there is no blinking reflex.
    • Diabetic Neuropathy:
      • Causes numbness in the feet in a sock-like manner.
      • Pain has a burning sensation.

    Nervous System Neoplasms

    • Most brain tumors in adults are above the tentorium cerebelli (supratentorial), while most in children are below the tentorium cerebelli (infratentorial).
    • Most CNS tumors are metastatic from other locations.
    • Gliomas are tumors that originate from glial cells.
    • Metastatic Tumors are the most common malignant tumor of the CNS.
      • Astrocytoma is the most common primary CNS neoplasm and a type of glioma.
        • Astrocytomas are derived from astrocytes.
        • Grade 1 astrocytomas are well-differentiated and not aggressive.
        • Some astrocytomas respond to radiation therapy.
      • Glioblastoma multiforme is a malignant astrocytoma (grade 4).
        • It is the most aggressive type of glioma.
        • Glioblastomas are the most common malignant glioma, representing about one-third of all cases.
        • Glioblastoma multiforme is the only CNS tumor that can cross the midline, creating a "butterfly" appearance.
      • Juvenile pilocytic astrocytoma is derived from astrocytes.
        • It accounts for a quarter of all brain tumors in children under 10 years old.
        • This tumor has a good prognosis and is easily operable.
      • Oligodendroglioma originates from oligodendrocytes.
        • It is most common during midlife and has a 5-10 year survival following surgery.
        • On radiographs, oligodendrogliomas may present with specks of calcification.
      • Ependymoma are derived from ependymal cells, which line the brain's ventricles.
        • When located in the brain, ependymomas are found in the fourth ventricle.
      • Medulloblastoma originates in the cerebellum.
        • It is primarily found in children and young adults.
        • Medulloblastomas are highly malignant and spread to the spinal cord through cerebrospinal fluid (CSF), metastasizing.
        • This tumor accounts for almost a quarter of all brain tumors in children.
      • Meningioma is a benign tumor that doesn’t invade other tissues.
        • It grows in the subdural space, within the dura mater.
        • Meningiomas cause compression of the surrounding brain tissue.
        • They are more common in women because they have progesterone receptors.
        • Meningiomas contain calcium layers and can form psammoma bodies.
      • Lymphoma
        • Primary brain lymphomas are of the B-lymphocyte type.
        • They occur in people with compromised immune systems such as those with AIDS.
    • Secondary Neoplasms
      • Metastasis to the brain is most common from lung cancer.
        • The most common types of metastases are from the lungs (most frequent), breast, skin, kidneys, and gastrointestinal tract.

    Craniopharyngioma

    • Craniopharyngiomas are most common in teenagers and young adults.
    • They usually have cholesterol crystal calcifications.
    • They are located above the sella turcica and can compress the hypothalamus, optic chiasm, and the third ventricle.

    Peripheral Nervous System Disorders

    • Guillain-Barré Syndrome
      • It is an autoimmune condition that often follows a viral infection and causes ascending paralysis.
      • Symptoms start with numbness and weakness in the lower limbs.
    • Myasthenia Gravis
      • It is an autoimmune condition that destroys neuromuscular junctions, leading to descending paralysis.
      • Initially, facial muscles are affected, leading to ptosis (drooping eyelids) and diplopia (double vision).
    • Neurofibromatosis
      • Type I neurofibromatosis (von Recklinghausen disease)
        • It is a peripheral type.
        • It causes multiple benign skin and peripheral nerve tumors.
        • It also leads to the development of café au lait spots (pigmented skin lesions).
      • Type II neurofibromatosis
        • It is a central type.
        • It causes bilateral acoustic neuromas (tumors of the eighth cranial nerve, vestibulocochlear nerve), which can lead to deafness.
        • It can also compress the seventh cranial nerve (facial nerve) due to its proximity to the eighth cranial nerve, leading to facial palsy.
    • Trigeminal Neuralgia (Tic Douloureux)
      • It affects all three branches of the fifth cranial nerve (trigeminal nerve), causing pain that is triggered by light touch to the face.
      • It usually occurs later in life.
    • Facial Paralysis (Bell's Palsy)
      • It affects the seventh cranial nerve (facial nerve), causing loss of facial muscle function.
      • It may result in an inability to completely close eyes (requiring eye drops as blinking reflex is lost).
    • Diabetic Neuropathy
      • It causes numbness in the feet in a "sock-like" distribution, sometimes with a burning sensation.

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