Pathology: Neurology
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Questions and Answers

Which of the following should always be examined in an animal with neurological disease?

  • Digestive system
  • Central nervous system (correct)
  • Peripheral nervous system
  • Respiratory system

    • The spinal cord should only be examined if there is a history of paresis or paralysis.

    False

    What solution is optimal for immersion fixation of the brain and spinal cord?

    10% buffered formalin solution

    Neurons are highly specialized postmitotic cells that are very susceptible to __________ and toxic substances.

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

    What is the primary reason for the serious consequences of tissue compression in the nervous system?

    <p>Limited room for expansion</p> Signup and view all the answers

    Match the types of cells in the nervous system with their functions:

    <p>Neurons = Transmit nerve impulses Glia = Support and protect neurons Ependymal cells = Line the ventricular system Schwann cells = Myelinate peripheral nerves</p> Signup and view all the answers

    Autolysis in the brain and spinal cord occurs at a slow rate due to their high lipid content.

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

    What should be worn when handling tissues of rabies suspects?

    <p>Additional protective gear</p> Signup and view all the answers

    What is the main cause of cervical vertebral stenotic myelopathy (CVSM) in horses?

    <p>Narrowing of the cervical vertebral canal</p> Signup and view all the answers

    Intervertebral disk disease primarily affects cats and dogs.

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

    Name the two types of herniations associated with intervertebral disk disease (IVDD).

    <p>Hansen type I and Hansen type II</p> Signup and view all the answers

    Cervical static stenosis affects horses between the ages of _______ to _______ years.

    <p>1, 4</p> Signup and view all the answers

    Match the types of nerve injuries with their descriptions:

    <p>Neuropraxia = Temporary paralysis without structural loss Axonotmesis = Disruption of axons but neural tube intact Neurotmesis = Complete or partial transection of the nerve</p> Signup and view all the answers

    Which type of herniation occurs without a history of trauma and may involve extrusion of degenerated disc material?

    <p>Hansen type I herniation</p> Signup and view all the answers

    Teratogens mainly act during the first third of pregnancy during the critical period of morphogenesis.

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

    What age range does cervical vertebral instability (dynamic stenosis) affect in horses?

    <p>8 to 18 months</p> Signup and view all the answers

    What function do interfascicular oligodendrocytes primarily serve?

    <p>Myelin production in the CNS</p> Signup and view all the answers

    Astrocytes are the least numerous cell type in the CNS.

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

    What are the primary components transported by the fast axonal anterograde transport system?

    <p>Membrane bound vesicles, neurotransmitters, and enzymes</p> Signup and view all the answers

    The brain's protective membranes are known as the _____ membranes.

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

    Match the following cell types with their primary function:

    <p>Neurons = Transmit signals Astrocytes = Repair and support Oligodendrocytes = Myelin production Microglia = Immunologic roles</p> Signup and view all the answers

    Which structure regulates the flow of cerebrospinal fluid?

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

    Schwann cells myelinate central nervous system nerves.

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

    What is the primary role of microglia in the CNS?

    <p>Immunologic roles including phagocytosis and immunoregulation</p> Signup and view all the answers

    Cerebrospinal fluid (CSF) is produced by the _____ choroid plexus.

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

    Match the following axonal transport types with their description:

    <p>Fast axonal anterograde = Transports materials down the axon Fast axonal retrograde = Returns materials to the cell body Slow axonal anterograde = Transfers cytoskeletal proteins Axonopathies = Diseases resulting from transport alterations</p> Signup and view all the answers

    What can cause axonopathies?

    <p>Alterations in transport systems</p> Signup and view all the answers

    Nerve fibers in the PNS can regenerate under certain circumstances.

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

    What is the main function of the blood-brain barrier?

    <p>To regulate the passage of substances between the bloodstream and the CNS</p> Signup and view all the answers

    What is one common cause of acute neuronal necrosis?

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

    The _____ layer is composed of strong dense collagenous tissue.

    <p>dura mater</p> Signup and view all the answers

    What happens to neurons during cessation of blood flow?

    <p>They can become lethal due to limited energy stores</p> Signup and view all the answers

    Chromatolysis is characterized by cell swelling and dispersal of Nissl substance.

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

    What is the term for the process of axonal degeneration with secondary myelin loss?

    <p>Wallerian degeneration</p> Signup and view all the answers

    The accumulation of _____ in aging neurons is known as lipofuscin.

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

    Match the following neuronal responses to their descriptions:

    <p>Astrocytosis = Increase in size and number of astrocytes Gemistocytic astrocytes = Abundant pink cytoplasm and eccentric nuclei Alzheimer Type II astrocytes = Typical of hepatic encephalopathies Satellitosis = Oligodendrocytes localized around injured neurons</p> Signup and view all the answers

    Which of the following represents a feature of acute degenerative change in neurons?

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

    Excitotoxicity can be caused by the excessive stimulation of neurons by inhibitory neurotransmitters.

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

    What type of neuronal injury may result from heavy metal intoxication?

    <p>Acute neuronal necrosis</p> Signup and view all the answers

    Activation of _____ in response to neuronal injury leads to the removal of necrotic neurons.

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

    Which process leads to the fragmentation of the axon following an injury?

    <p>Wallerian degeneration</p> Signup and view all the answers

    Astrogliosis refers to the decrease in size and number of astrocytes in the brain following injury.

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

    Name a type of neuron damage associated with viral diseases.

    <p>Intraneuronal inclusion bodies</p> Signup and view all the answers

    In the central nervous system, degeneration of myelin sheaths is observed in _____ degeneration.

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

    Which of the following is a feature of chronic neuronal necrosis?

    <p>Loss of transsynaptic afferent input</p> Signup and view all the answers

    Which of the following diseases is associated with immunological destruction in animals?

    <p>Marek’s disease</p> Signup and view all the answers

    Cytotoxic edema is primarily a result of vascular injury and breakdown of the blood-brain barrier.

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

    What is the common response of ependymal and choroid plexus epithelial cells to injury?

    <p>Atrophy, degeneration, necrosis</p> Signup and view all the answers

    The term for inflammation of the meninges is called __________.

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

    Which type of edema is most commonly observed in the CNS of animals?

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

    Ependymitis is caused primarily by direct physical trauma.

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

    What are Gitter cells?

    <p>Macrophages that phagocytose debris of dead neurons and glial cells</p> Signup and view all the answers

    The predominant injury pattern from traumatic lesions is typically __________.

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

    Match the following conditions with their corresponding characteristics:

    <p>Meningitis = Inflammation of the meninges Vasogenic edema = Caused by breakdown of the blood-brain barrier Coup injury = Trauma occurring at the site of impact Leptomeningitis = Inflammation of the leptomeninges</p> Signup and view all the answers

    What can result from ischemic lesions in the CNS?

    <p>All of the above</p> Signup and view all the answers

    Hydrocephalus refers to inflammation of the brain.

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

    What is a common consequence of severe endothelial injury in the CNS?

    <p>Vascular inflammation and thrombosis</p> Signup and view all the answers

    Interstitial edema occurs due to elevated ventricular __________ pressure.

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

    Which condition is characterized by the accumulation of fibrocartilage in spinal arteries?

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

    Concussions result in permanent structural damage to the brain.

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

    What is the primary cause of acquired hydrocephalus in animals?

    <p>Obstructive causes</p> Signup and view all the answers

    External hydrocephalus refers to fluid accumulation within the ventricular system.

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

    Name one viral infection that can cause cerebellar hypoplasia in domestic animals.

    <p>Feline panleukopenia virus</p> Signup and view all the answers

    Hydrocephalus is characterized by the abnormal accumulation of __________ fluid.

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

    Match the following terms with their definitions:

    <p>Encephalitis = Inflammation of the brain Myelitis = Inflammation of the spinal cord Meningitis = Inflammation of the meninges Choroiditis = Inflammation of the choroid plexus</p> Signup and view all the answers

    Which of the following viruses is responsible for causing 'hairy-shaker' lambs?

    <p>Border disease virus</p> Signup and view all the answers

    Abscesses in the nervous system are primarily caused by viral infections.

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

    What type of hydrocephalus involves bilateral and symmetrical dilation of the ventricular system?

    <p>Communicating hydrocephalus</p> Signup and view all the answers

    Certain bacterial infections, like those caused by __________, can lead to neonatal bacterial suppurative meningitis.

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

    What is a common complication of poorly preserved silage in ruminants?

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

    Ependymitis refers to the inflammation of the meninges.

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

    Which condition affects the brainstem and is associated with the consumption of poorly preserved silage?

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

    The inflammation of the meninges that involves the pia-arachnoid is called __________.

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

    Match the bacterial disease with its primary outcome:

    <p>Listeriosis = Meningoencephalitis Histophilus somni = Septicaemia and meningoencephalitis Neonatal meningitis = Suppurative meningitis Abscesses = Localized infections</p> Signup and view all the answers

    What is the primary cause of equine protozoal myeloencephalitis (EPM)?

    <p>Sarcocystis neurona</p> Signup and view all the answers

    Vaccination of pregnant dogs poses no risk to their puppies.

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

    Name a definitive host for Sarcocystis neurona.

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

    Dogs shed oocysts in their __________ after being infected with Neospora caninum.

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

    Match the following diseases with their associated agents:

    <p>EPM = Sarcocystis neurona Neosporosis = Neospora caninum BSE = Bovine spongiform encephalopathy Scrapie = Prion disease</p> Signup and view all the answers

    Which clinical sign is commonly associated with EPM?

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

    What is a common clinical sign of viral infections affecting the central nervous system?

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

    Viral CNS infections usually cause the formation of pus in the brain.

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

    The lesions in TSEs are primarily grossly visible in the brain.

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

    What type of lesions characterize EPM in severe cases?

    <p>Multifocal acute hemorrhage</p> Signup and view all the answers

    Which virus is responsible for causing canine herpesviral encephalitis?

    <p>Canine herpesvirus 1</p> Signup and view all the answers

    The presence of _______________ is indicative of rabies in infected neural tissues.

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

    Neosporosis is an important cause of __________ in bovines.

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

    Match the following viruses with their associated diseases:

    <p>Feline infectious peritonitis virus = Leptomeningitis and encephalomyelitis Canine distemper virus = Distemper encephalomyelitis Equine herpesvirus 1 = Myeloencephalopathy Rabies virus = Lymphocytic polioencephalomyelitis</p> Signup and view all the answers

    What is the causative agent of toxoplasmosis?

    <p>Toxoplasma gondii</p> Signup and view all the answers

    Prion diseases are characterized by inflammatory changes in the brain.

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

    Which of the following is NOT a common effect of herpesvirus infections in the CNS?

    <p>Bacterial Growth</p> Signup and view all the answers

    Which of the following is a common clinical sign of hepatic encephalopathy?

    <p>Fine head tremors</p> Signup and view all the answers

    The incubation period for rabies infections can last for several months.

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

    Copper deficiency causes congenital defects in lambs.

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

    What histological change is a hallmark of transmissible spongiform encephalopathies?

    <p>Neuronal vacuolation</p> Signup and view all the answers

    The primary route for Neospora caninum infection in cattle is through __________.

    <p>transplacental transmission</p> Signup and view all the answers

    What is the primary cause of equine laryngeal hemiplegia?

    <p>Denervation atrophy of the left recurrent laryngeal nerve</p> Signup and view all the answers

    What is the primary target tissue in malignant catarrhal fever?

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

    Match the following mycotic diseases with their associated characteristics:

    <p>Aspergillus = Opportunistic infections Cryptococcus neoformans = Affinity for CNS Candida = Opportunistic infections Histoplasma capsulatum = Systemic fungal infection</p> Signup and view all the answers

    Perennial rye-grass staggers is caused by the fungus __________.

    <p>Neotyphodium lolii</p> Signup and view all the answers

    Canine distemper virus spreads to the brain and infects ________ and ________ cells.

    <p>astrocytes, microglia</p> Signup and view all the answers

    Match the following CNS tumors with their characteristics:

    <p>Astrocytoma = Common in cerebrum and thalamus Oligodendroglioma = Soft and well-demarcated tumor Oligoastrocytoma = Mixed tumor of astrocytes and oligodendrocytes</p> Signup and view all the answers

    Which condition is characterized by widespread necrotizing vasculitis due to endothelial cell infection?

    <p>Equine herpesviral myeloencephalopathy</p> Signup and view all the answers

    The rabies virus has a short clinical course lasting only a few hours.

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

    Which of these is a histopathological finding in hepatic encephalopathy?

    <p>Microcavitation of myelin</p> Signup and view all the answers

    Oligodendrogliomas are primarily reported in cats.

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

    Identify one primary mode through which neurotropic viruses enter the CNS.

    <p>Retrograde axonal transport</p> Signup and view all the answers

    In horses, spinal cord involvement in rabies is more common than _______ involvement.

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

    What is the typical recovery time for animals affected by perennial rye-grass staggers after removal from toxic pasture?

    <p>3 weeks</p> Signup and view all the answers

    Match the term with its definition.

    <p>Necrosis = Cell death due to severe injury or disease Apoptosis = Programmed cell death Vasculitis = Inflammation of blood vessels Encephalitis = Inflammation of the brain</p> Signup and view all the answers

    Histopathological findings in copper deficiency associated with swayback include __________ in the spinal cord.

    <p>axonal degeneration with demyelination</p> Signup and view all the answers

    Which type of nervous system tumor originates from the nervous system itself?

    <p>Primary tumors</p> Signup and view all the answers

    What is a common cause of polioencephalomalacia (PEM) in ruminants?

    <p>Thiamine deficiency</p> Signup and view all the answers

    Lead poisoning is rarely observed in swine.

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

    What is the primary mycotoxin responsible for mycotoxic leukoencephalomalacia in horses?

    <p>fumonisin B1</p> Signup and view all the answers

    The disease characterized by tail paralysis and urinary incontinence in horses is called __________.

    <p>Polyneuritis equi</p> Signup and view all the answers

    Match each condition to its characteristic feature:

    <p>Polioencephalomalacia = Thiamine deficiency Salt poisoning = Increased sodium in CSF Lead poisoning = Acute symptoms within 24 hours Mycotoxic leukoencephalomalacia = Mouldy corn exposure</p> Signup and view all the answers

    What clinical signs are associated with salt poisoning in livestock?

    <p>Severe dehydration and neurological symptoms</p> Signup and view all the answers

    Focal symmetrical encephalomalacia is primarily associated with high starch diets in sheep and cattle.

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

    What type of inflammation is typically observed in chronic cases of Polyneuritis equi?

    <p>granulomatous inflammation</p> Signup and view all the answers

    The mycotoxin responsible for neurological impairment in horses due to mouldy corn is __________.

    <p>fumonisin B1</p> Signup and view all the answers

    What is a common gross observation in the brains affected by gatti?

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

    Malacia refers to the hardening of tissue in the CNS.

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

    What are the principal clinical signs of polioencephalomalacia in ruminants?

    <p>Blindness, convulsions, nystagmus, head pressing</p> Signup and view all the answers

    Match each disease to its respective animal group:

    <p>Salt poisoning = Swine and sheep Lead poisoning = Cattle Mycotoxic leukoencephalomalacia = Horses Focal symmetrical encephalomalacia = Lambs and calves</p> Signup and view all the answers

    Oedema, increased pressure, and necrosis in the brain can occur after regaining access to water following dehydration from salt poisoning.

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

    What is the most abundant protein found in normal cerebrospinal fluid (CSF)?

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

    Increased protein levels in CSF are always associated with an increase in cellularity.

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

    What is the maximum typical total nucleated cell count per microliter of CSF in dogs?

    <p>5</p> Signup and view all the answers

    Turbidity in cerebrospinal fluid can be caused by increased numbers of __________ and/or __________.

    <p>cells, protein</p> Signup and view all the answers

    Match the pleocytosis type with its common cause:

    <p>Neutrophilic pleocytosis = Bacterial infections Lymphocytic/monocytic pleocytosis = Viral diseases Eosinophilic pleocytosis = Parasitic infections Neoplastic cells = Neural lymphoma</p> Signup and view all the answers

    What method is commonly used to prepare cells for cytological evaluation of CSF?

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

    Normal CSF contains erythrocytes in significant quantities.

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

    What preliminary screening test is suggested for estimating CSF protein concentration?

    <p>Urine protein reagent strips</p> Signup and view all the answers

    The Pandy test indicates the presence of increased __________ concentration in CSF.

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

    Which of the following is a common method for identifying bacterial meningitis in cloudy CSF?

    <p>Bacterial culture</p> Signup and view all the answers

    What type of tumors are most commonly benign and associated with the meninges?

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

    Choroid plexus tumors can only be carcinomas, due to their cellular characteristics.

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

    Which breed of dog shows a significant predisposition to choroid plexus tumors?

    <p>Golden Retriever</p> Signup and view all the answers

    Degenerative changes in the choroid plexus often lead to the formation of __________ granulomas.

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

    Match the following types of CNS tumors with their characteristics:

    <p>Choroid plexus tumors = May be papillomas or carcinomas Meningiomas = Commonly benign and located in the meninges Hematopoietic tumors = Can metastasize to the CNS from other locations Peripheral nerve sheath tumors = Can be benign or malignant forms</p> Signup and view all the answers

    Which of the following is a characteristic of cerebrospinal fluid (CSF)?

    <p>It should be collected in sterile, plain tubes.</p> Signup and view all the answers

    Pleocytosis refers to a decrease in total nucleated cell count in cerebrospinal fluid.

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

    What is the main function of cerebrospinal fluid?

    <p>To deliver nutrients and remove waste metabolites from the CNS.</p> Signup and view all the answers

    The normal total nucleated cell count in CSF for dogs is between __________ cells/μl.

    <p>0 to 5</p> Signup and view all the answers

    Match the following CSF abnormalities with their possible indications:

    <p>Pink or red discoloration = Presence of blood Xanthochromia = Pathologic hemorrhage Erythrophagocytosis = Evidence of erythrocyte breakdown Low protein concentration = Normal CSF characteristic</p> Signup and view all the answers

    Which of the following is a potential complication when collecting CSF from a patient with cranial trauma?

    <p>Risk of edema and raised intracranial pressure.</p> Signup and view all the answers

    Cerebrospinal fluid can be collected safely from any site in the body.

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

    What is the principal protein found in normal cerebrospinal fluid?

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

    The reference range for protein concentration in CSF for dogs is __________ mg/dL.

    <p>10-40</p> Signup and view all the answers

    Which type of hematopoietic tumor may primarily originate in the central nervous system?

    <p>None of the above</p> Signup and view all the answers

    Study Notes

    Postmortem Examination of the Nervous System

    • Central nervous system (CNS) examination is mandatory for animals with neurological diseases or inconclusive major organ lesions.
    • Spinal cord and canal examination is essential if there is evidence of paresis or paralysis.
    • Focused CNS examination is more efficient when specific lesion locations are identified through previous diagnostics like MRI.
    • When a specific lesion cannot be localized, representative sampling from multiple anatomical regions is necessary.
    • Detailed inspections of the brain include assessing cerebrum and cerebellum size, malformations, symmetry, swellings, and meningeal alterations.
    • Rapid autolysis occurs in brain and spinal cord due to high lipid content; immersion fixation in 10% buffered formalin for 5-10 days is recommended.
    • Handle rabies or zoonotic disease suspects with caution and appropriate protective gear to prevent exposure.

    Pathology of the Nervous System

    • Anatomy and histology of the CNS limit room for expansion in disease states, making even slight compression hazardous.
    • Neuronal cells are highly specialized and vulnerable to hypoxia and toxins, featuring distinct structures (cell body, dendrites, axon) and functions.
    • Various CNS cells are involved in pathology: neurons, glia, ependymal cells, meninges, Schwann cells, endothelial cells, and pericytes.

    Neurons

    • Neurons are large, specialized postmitotic cells with significant energy requirements but limited oxygen reserves; they cannot regenerate.
    • Neurons are organized into functional groups for efficiency and communication.
    • Transport systems include fast anterograde and retrograde systems and a slow anterograde system for essential proteins, responsible for injury responses termed axonopathies.

    Astrocytes, Oligodendrocytes, Microglia

    • Astrocytes act as interstitial cells, providing support, forming the blood-brain barrier, and aiding in repair.
    • Oligodendrocytes are crucial for CNS myelination with two types: interfascicular (myelin production) and satellite (environment regulation).
    • Microglia serve as phagocytes, playing essential roles in immune response and tissue integrity.

    Cerebrospinal Fluid and Meninges

    • Cerebrospinal fluid (CSF) is secreted by the choroid plexus, delivering nutrients, removing waste, and acting as shock protection.
    • The meninges consist of three layers: dura (strong collagen), arachnoid (multi-layered), and pia mater (vascularized, thin layer).

    Blood-Brain Barrier

    • Formed by tight junctions of endothelial cells, basement membranes, and astrocyte foot processes, it protects the CNS environment.

    Understanding CNS Injuries

    • Varying vulnerability to injury among CNS cells: neurons (highest), oligodendroglia (moderate), astrocytes (lower), microglia (minimal), blood vessels (lowest).
    • Neurons cannot regenerate; CNS injuries often lead to astrocyte proliferation for healing.
    • Space-occupying lesions in the CNS create clinical signs via compression or displacement.
    • The CNS shows low resistance to infection and injury.

    Neuronal Responses to Injury

    • Neurons are prone to necrosis due to energy demands; common results include chromatolysis, acidophilic necrosis, and unique inclusions based on disease.
    • Neuronal death can follow an apoptotic or necrotic pathway based on injury type and receptor activation.

    Axonal Changes and Wallerian Degeneration

    • Loss of axonal integrity leads to degeneration and secondary myelin loss known as Wallerian degeneration.
    • Phagocytosis of damaged cells by Schwann cells and macrophages shows clear regenerative pathways in PNS but limited in CNS.

    Common Responses of CNS Cells to Injury

    • Astrocytes undergo hypertrophy and hyperplasia; responses include gemistocytic and Alzheimer Type II appearances.
    • Oligodendrocytes swell or hyperplasia; demyelination may occur due to factors such as infections or nutritional deficiencies.
    • Microglia exhibit alterations through hypertrophy and phagocytosis of cellular debris.

    Traumatic Injuries

    • Traumatic CNS lesions often feature hemorrhages and tissue necrosis, which can lead to further complications like infection from fractures.
    • Common traumatic injuries include concussion (transient loss of consciousness), contusions (hemorrhage with retained tissue architecture), and skull fractures.

    Other Vascular Disorders

    • Ischemia is a critical factor in many CNS diseases; outcomes depend on vessel damage extent and duration of ischemia.
    • Systemic vasculitis, bacterial thrombi, and embolic events can lead to severe CNS complications, including ischemic and hemorrhagic lesions.### Intervertebral Disk Disease (IVDD)
    • Degenerative changes in intervertebral discs occur in non-chondrodystrophic breeds due to aging or in chondrodystrophic breeds at an early age.
    • Herniations happen mainly without trauma history, often between T10 and L3 or in the cervical area.
    • Annulus fibrosus degeneration may lead to ruptures (Hansen type I herniation) resulting in extruded degenerated material.
    • Protrusions of the annulus fibrosus into the spinal canal are identified as Hansen type II herniation.

    Cervical Vertebral Stenotic Myelopathy/Wobbler Syndrome (CVSM)

    • CVSM is characterized by ataxia and weakness caused by narrowed cervical vertebral canal and spinal cord compression.
    • In horses, it manifests as cervical static stenosis (ages 1-4) and cervical vertebral instability (ages 8-18 months).
    • Static stenosis occurs due to canal narrowing at C5-C7, while dynamic stenosis involves canal narrowing during neck flexion at C3-C5.

    Nerve Injuries

    • Neuropraxia results in temporary nerve paralysis due to pressure or blood flow obstruction, without structural damage.
    • Axonotmesis involves disrupted axons but intact neural tubes, with potential for recovery.
    • Neurotmesis refers to complete or partial nerve transection, likely resulting in permanent injury.

    Central Nervous System Malformations

    • CNS malformations are common in domestic animals, with potential inherited or teratogenic causes.
    • Teratogens affect primarily during early pregnancy morphogenesis; viral infections can have broader timing impacts.

    Hydrocephalus

    • Characterized by abnormal cerebrospinal fluid accumulation leading to ventricular enlargement.
    • Internal hydrocephalus pertains to ventricular fluid; external involves fluid in the arachnoid space, while communicating hydrocephalus shows bilateral dilation without detectable lesions.
    • Acquired hydrocephalus is frequently obstructive, sometimes caused by in utero infections leading to duct stenosis.

    Cerebellar Hypoplasia

    • Common congenital defect associated with parvoviruses and pestiviruses infection during cerebellum development.
    • Maternal viral infections transplacentally infect neuroblast cell precursors, leading to hypoplasia and dysplasia of the granular cell layer.

    Viral Infections Causing CNS Developmental Defects

    • Bovine viral diarrhoea virus leads to various disorders, including hypomyelinogenesis and skeletal defects.
    • Border disease virus causes tremors and 'hairy-shaker' lambs by infecting oligodendroglia and astroglia.
    • Classical swine fever virus can cause cerebellum hypoplasia.
    • Feline panleukopenia virus adversely affects kittens' cerebellum during rapid development stages.

    Inflammatory Lesions Terminology

    • Encephalitis: Brain inflammation.
    • Myelitis: Spinal cord inflammation.
    • Encephalomyelitis: Combined brain and spinal cord inflammation.
    • Ependymitis: Inflammation of ependymal cells.
    • Choroiditis: Inflammation of choroid plexus.
    • Meningitis: Meningeal inflammation; subdivided into leptomeningitis (pia-arachnoid) and pachymeningitis (dura).

    Infectious Diseases of the Nervous System

    • Pyogenic bacteria can cause localized abscesses from various infection routes, with key bacteria including Streptococcus, Staphylococcus, and Brucella.
    • Neonatal bacterial suppurative meningitis can arise from several bacteria, presenting with cloudiness in meninges.
    • Septic embolism as a complication of endocarditis can lead to CNS infections.

    Important Bacterial Diseases of the CNS

    • Listeriosis in ruminants can cause encephalitis, often due to poor silage with Listeria monocytogenes.
    • Infectious thrombotic meningoencephalitis caused by Histophilus somni results in vasculitis and potential neurological signs, including ataxia and circling.

    Viral Infections of the CNS

    • Viruses like FIPV can cause severe CNS lesions through inflammatory reactions.
    • Herpesviruses, specifically alphaherpesviruses, lead to necrosis and inflammation within the CNS.
    • Canine herpesvirus 1 results in fatal disease in young puppies.
    • Equine herpes virus 1 and 4 cause clinical signs of ataxia and paralysis, with CNS involvement through endothelial cell infection.

    Prion Diseases

    • Transmissible spongiform encephalopathies (TSE) are characterized by spongiform encephalopathy due to PrPSc accumulation.
    • TSEs include scrapie, Bovine spongiform encephalopathy (BSE), and Chronic wasting disease, with varying clinical signs and patterns of neuronal vacuolation.

    Mycotic and Algal Diseases

    • Mainly opportunistic infections in immunocompromised hosts; Cryptococcus neoformans specifically targets the CNS, causing granulomatous infections.
    • Inflammatory responses typically involve neutrophils and macrophages resulting in severe clinical manifestations.### Gatti and Nervous System Infections
    • Common in cats, dogs, and horses; organisms enter through the cribriform plate due to nasal/sinus infections or pulmonary leukocytic trafficking.
    • Gross examination shows multiple small cysts in the brain, with yeast appearing spherical (2-20 μm) and surrounded by a non-staining capsule.

    Idiopathic Inflammatory Diseases

    • Neuritis of the cauda equina (Polyneuritis equi):
      • Clinical signs include tail paralysis, urinary incontinence, faecal retention, weakness, and muscle atrophy.
      • Etiology is unknown, potentially autoimmune; may follow viral infection.
      • Affects sacral and coccygeal nerves; grossly, affected roots are thickened and discolored due to chronic hemorrhage, with granulomatous inflammation and fibrosis microscopically.

    Degenerative Diseases of the Nervous System

    • Malacia and Malacic Diseases:

      • Malacia indicates softening due to necrosis; encephalomalacia is brain necrosis, myelomalacia is cord necrosis.
      • Softening of grey matter termed poliomalacia, and white matter leukomalacia, with pathology tied to specific syndromes.

    • Polioencephalomalacia (PEM):

      • Affecting ruminants, characterized by edema and laminar necrosis; largely caused by thiamine deficiency due to diet changes.
      • Clinical signs include blindness and convulsions; lesions fluoresce under UV light.
      • Histology shows laminar necrosis with shrunken neurons.

    • Salt Poisoning/Water Deprivation:

      • Occurs in swine, sheep, cattle post excessive sodium chloride consumption; complications arise from dehydration.
      • Pathogenesis involves Na+ movements causing cerebral edema due to osmotic gradients.
      • Lesions include cerebral edema and laminar cortical neuronal loss.

    • Lead Poisoning:

      • Common in farm animals; acute symptoms include muscle tremors and recumbency; subacute cases can exhibit laminar cortical necrosis.

    • Focal Symmetrical Encephalomalacia (FSE):

      • Seen in lambs and calves fed high-starch diets; epsilon toxin from C. perfringens type D induces brain necrosis.
      • Characterized by bilateral malacia and hemorrhage in brain regions.

    • Mycotoxic Leukoencephalomalacia:

      • Results from chronic exposure to mouldy corn in horses; caused by fumonisin B1.
      • Clinical signs include impaired vision and staggering; white matter necrosis occurs.

    Other Degenerative Diseases

    • Hepatic Encephalopathy (HE):

      • Metabolic disorder resulting from diminished liver function; leads to impaired detoxification.
      • Histopathological findings include microcavitation of myelin and Alzheimer-type II astrocytes.

    • Copper Deficiency:

      • Causes swayback in lambs via congenital deficiency and enzootic ataxia post-birth.
      • Histology shows axonal degeneration and demyelination.

    • Perennial Ryegrass Staggers:

      • Affects ruminants in regions like Australia and Europe; due to neurotoxic lolitrems.
      • Symptoms include tremors and ataxic gait; often resolves within weeks after removing from pasture.

    • Equine Laryngeal Hemiplegia:

      • Causes airway obstruction leading to “roaring” during exertion; linked to idiopathic degeneration of the recurrent laryngeal nerve.

    Neoplastic Diseases of the Nervous System

    • Neoplasms categorized as either CNS or PNS; primary originate within the system while secondary originate elsewhere.
    • Astrocytomas: Common intracranial tumors, especially in brachycephalic breeds; malignancy dictates structural changes.
    • Oligodendrogliomas: Typically found in brachycephalic breeds, characterized by a well-demarcated gray appearance.
    • Meningiomas: Common in dogs and cats, generally benign; associated with low metastasis risk.
    • Hematopeitic Tumors: Can metastasize to CNS; examples include lymphosarcoma and malignant melanoma.

    Cholesterol Granulomas

    • Aging-related change in choroid plexus, particularly in older horses due to repeated hemorrhage; large granulomas can lead to obstructive hydrocephalus.

    Cerebrospinal Fluid (CSF) Analysis

    • CSF serves crucial functions in CNS health, primarily formed by the choroid plexus.
    • Normal CSF is clear, colorless, low in protein, and acellular, with species-specific variations in total nucleated cell count.
    • CSF collection indicated for neurologic diseases but contraindicated in cases of cranial trauma.
    • Analysis assesses colour, turbidity, protein concentration, and total cell count to differentiate disease processes.
    • Macroscopic evaluation can reveal blood presence, whereas turbidity indicates increased cells/proteins.
    • Increased protein may suggest various CNS disorders; cellular stability can be enhanced post-collection with fresh plasma addition.

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    Description

    This quiz covers the essential procedures in performing a postmortem examination on the central nervous system (CNS) of animals, particularly those with neurological diseases. It emphasizes the importance of examining the CNS in cases of paresis or paralysis and provides guidance on localized examination based on clinical findings.

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