Pathophysiology of the Central Nervous System PDF

Cerebrovascular accidents, CVA(stroke syndrome ) CVA are the leading cause of disability worldwide  Occurs mainly in those over 65Y  More common in men.  High risk patients are  type 2 diabetes and  hypertensive patients 1...

Cerebrovascular accidents, CVA(stroke syndrome ) CVA are the leading cause of disability worldwide  Occurs mainly in those over 65Y  More common in men.  High risk patients are  type 2 diabetes and  hypertensive patients 1 2 3 4 Cerebrovascular accidents, Cerebrovascular stroke [ischemic] CVA(stroke syndrome ) Results from sudden interruption of blood supply to the brain,  Ischemic which precipitates neurologic  Partial (TIA)  Due to stable dysfunction atherosclerotic plaque  Cerebrovascular stroke involving the extracranial or  Ischemic intracranial arteries.  Partial  Complete  TIA[ transient ischemic  Occlusions of a cerebral attacks] blood vessel  Complete ( cerebral  Cerebral thrombosis infarction) (unstable plaque)  Cerebral thrombosis  Embolism  Cerebral embolism  Haemorrhagic 5 6  Hemorrhage. Leading to Partial ischemic stroke haemorrhaagic stroke  Transient ischemic attacks[TIA] ;  Are temporary decreases in brain blood flow [thrombus breaks up quickly] resulting in brief changes in brain function e.g. changes in  vision, Stable plaque leading  speech, to ischemia[ TIA]  motor function,  dizziness or loss of consciousness.  All the neurologic deficits are completely clear within 24 hours leaving no residual dysfunction. Thrombus or Embolus  Without definitive diagnosis and treatment 80% of blocking an artery persons have recurrence of symptoms by 1 year, and leading to ischemic mostly will develop complete stroke. stroke 7 8 Cerebral thrombosis  Stable plaque Unstable plaque Narrowing Occlusion  Usually the thrombus builds up over several hours, and the individual experience slowly progressive neurologic dysfunction called stroke - in - evolution.  Persistent vessel obstruction will result in cerebral infarction unless perfusion is restored rapidly. This is termed a completed stroke. 9 10  Embolic stroke  Involves fragments that break from a thrombus formed outside the brain ,in Thrombosis the heart, aorta, or common carotid.  The thrombus then travels distally into one of the cerebral vessels, most commonly the middle cerebral artery. Cerebral  Leading to its occlusion and complete infarction stroke 11 12   Risk factors for cardio-embolic stroke  Clinical manifestations of thrombotic stroke vary,  atrial fibrillation, depending on the artery obstructed · Because the middle cerebral artery is most affected by  myocardial infarction, and atherothrombotic and embolic disease, common manifestations  valvular heart disease. of acute brain infarction are: Hemiparesis [weakness]or hemiplegia [paralysis] —  Individuals with these cardiovascular Decreased motor ability on the affected side disorders are usually placed on a Hemisensory loss —Decreased sensation on the affected side regimen of anticoagulation therapy[ Aphasia Subsequent development of cerebral oedema can lead to: warfarin] Decreased levels of consciousness to prevent this dreaded complication. Possible brain herniation and death 13 14 Aphasia  Stroke Test: Talk, Wave, Smile  Aphasia results from damage to  The F.A.S.T. test helps spot symptoms of stroke. It stands for: the portion of the brain involved  Face. Ask for a smile. Does one side droop? in creating and interpreting  Arms. When raised, does one side drift down? language.  Speech. Can the person repeat a simple sentence? Does  Expressive aphasia; he or she have speech difficulty or slur words?  is the term for problems communicating using spoken or written language.  Receptive aphasia;  refers to problems understanding language 15 16  Cerebral haemorrhage  Haemorrhagic (leakage of blood from a vessel causes compression of brain tissue and spasm of adjacent vessels  Intracerebral haemorrhage  Subarachnoid haemorrhage 17 18 Hemorrhagic stroke In haemorrhagic stroke Hemorrhagic stroke(intracranial hemorrhage) Is the third most common cause of  Blood is ejected through the cerebrovascular accident. damaged wall of the vessel Causes ;is most often associated with : into the surrounding brain  Hypertension.  Congenital aneurysms or vascular tissue and can leak into the malformations. ventricles.  Condition that is associated with an increased risk for bleeding, including  The expanding collection of thrombocytopenia (e.g., caused by autoimmune intracerebral blood  disease [ITP], drugs or bone marrow disease)  Coagulopathies such as  liver disease, ( hematoma ) compresses  haemophilia, and surrounding tissues, resulting  iatrogenic anticoagulation.  Head trauma in ischemia and increasing  Elicit drug use intracranial pressure. 19 20  Clinical manifestation  Intracerebral haemorrhage is most often associated with Blood ejected  Sudden onset of severe headache and vomiting out of a vessel  Loss of consciousness and coma.  The extent of focal neurologic deficits depends upon the location and extent of the bleeding.  The clinical status of the individual may deteriorate rapidly despite intervention. 21 22 Chronic disorders of neurologic dysfunction Seizure disorders 23 24   Seizure disorder is characterized by recurrent episodes of abnormal electrical impulses in the brain[ excessive electrical activity of the brain].  There are two types of seizures:  Causes  generalized  Primary ;  tonic –clonic (grand mal),  epilepsy  Absence (petit mal),  Secondary  Febrile  Head injury,  Rapid recurring or status epilepticus  meningitis,  partial, or focal  brain tumors,  simple or  complex.  Vascular disease and  Metabolic disorders (electrolyte imbalance, fever, acidosis) 25 26 A. Generalized Seizures Generalized Seizures; classification  1.Tonic – clonic  Generalized seizures excessive electrical activity seizures ,  formerly known as grand begin in one area of the brain and mal seizures, involve rapidly spread throughout both hemispheres of  dramatic tonic –clonic muscle contractions, the brain.  loss of consciousness, and a recovery period[postictal Patients who have a generalized seizure usually  state] characterized by experience a loss of consciousness resulting from confusion and exhaustion. Most seizures last from 30 this massive electrical activity throughout the brain.  seconds to two minutes. A  Generalized seizures are further classified into the seizure that lasts longer than five minutes is a following five types: medical emergency. 27 28  Aura ;  clonic (twitching or jerking) phases of muscle activity.  Tonic-clonic seizures may start with aura. The person Jerking movements affect the face, arms and legs, may experience changes in sensation, mood or emotion becoming intense and rapid. After one to three minutes, leading up to the tonic -clonic seizure. the jerking movements slow down and the body relaxes, sometimes including the bowel or bladder.  Tonic-clonic seizures involve both  Postictal state ;  tonic (stiffening) ,the person loses consciousness and may fall. There may be saliva or foam coming from the  After a seizure, the person may remain unconscious for mouth. If the person inadvertently bites their tongue or several minutes as the brain recovers from the seizure cheek, blood may be visible in the saliva. Stiffness of the activity. He or she may appear to be sleeping or snoring. chest muscles may impair breathing, the person’s face Gradually the person regains awareness and may feel may look bluish. confused, exhausted, physically sore, sad or embarrassed for a few hours. 29 30 Actions to be taken in case of seizures Generalized Seizures;  a. Loosening restrictive clothing classification, cont.  c. Removing the pillow and raising padded side rails  2.Absence seizures ,  2nd most common type of epilepsy formerly known as  d. Positioning the client to side. if possible. with the petit mal seizures , head flexed forward  involve abrupt, brief ( 10-15 second) periods of staring ,  E. Make sure the area around their body is clear of motionless ,and stoppage of speaking.  Also can cause rapid blinking objects that could hurt them.  Absence seizures occur commonly in children and  Time the seizure. frequently disappear at puberty.  Don’t  Put anything in the mouth  Restraining the Patients ’s limbs 31 32  B. Partial Seizures  Status epilepticus,  Partial seizures , also called focal seizures,  potentially the most dangerous of seizure conditions, is  Excessive electrical activity involve one area of the brain and a state in which seizures rapidly recur again and again, do not spread throughout the entire organ. with no periods of recovery.  It result in intense brain metabolism. Ischemic brain  Simple partial[focal]may involve a single muscle damage may result. movement or sensory alteration, such as a strange taste or smell.  Complex partial seizures involve complex sensory changes such as hallucinations, mental distortion, changes in personality, loss of consciousness. 33 34 Degenerative disease  Multiple sclerosis[ MS]  It is relatively common disorder, involving destruction of CNS myelin[ in the spinal cord and brain] , sparing the peripheral nervous system  Pathophysiology ;  Onset usually between 20-50  It involves an autoimmune process that develops when a years  Female/male ratio is 2:1 previous viral insult to the nervous system has occurred  Myelin sheath is important for in a genetically susceptible individual. normal nerve conduction  May be related to vitamin D deficiency Without myelin there is slow nerve conduction 35 36   The roots of MS remain mysterious. It's most common in regions far from the equator, including Scandinavia and other parts of Northern Europe. These areas get less sunlight, so some researchers believe that vitamin D (the "sunshine vitamin") may be involved. Research suggests a possible link between vitamin D deficiency and autoimmune disorders, but studies are ongoing. Genetics appear to play a role, as well. 37 38 Clinical manifestations  Precipitating factors ;  Vision changes , with partial or complete loss of vision, usually in  Viral Infection, Trauma, Pregnancy one eye at a time, often with pain during eye movement.Double  Major manifestations vision. Blurrd vision  Initial syndromes followed by remissions [ remission and  These symptoms may lead to frequent tripping or difficulty relapses]and walking.  Established syndrome with no remissions.  Multiple sclerosis symptoms may also include:  Slurred speech  Symptoms  Fatigue  Depending on where the damage occurs, symptoms may include  Dizziness problems with  Tingling or pain in parts of your body  Numbness of one of the limbs ,or weakness  Problems with sexual, bowel and bladder function  Tremors , and Difficulty with coordination (ataxia) and muscle control leading to loss of balance, or unsteady gait 39 40 Parkinson disease ;  Pathogenesis ;  Basal ganglia loss of neurons with depletion of  Commonly occurring degenerative disorder of the dopamine , an inhibitory neurotransmitter. basal ganglia. Leading to abnormal movement called  Clinical picture parkinsonism.  Symptoms of Parkinson’s disease often begin on one side  Causes of the body and over time affect the entire body.  Primary  Tremors at rest (resting tremors, pill rolling) or when  Secondary to the patient is stressed and improves with deliberate  trauma movement.  infection  Muscle rigidity (stiffness)  neoplasma  Masked face  Shuffling gate  Akinesia (poverty of movement) 41  S lowness of movement, and postural instability 42   amyloid plaques and neurofibrillary tangles.  Amyloid plaques, which are found in the tissue between the nerve cells, are unusual clumps of a protein called beta amyloid along with degenerating bits of neurons and other cells.  Neurofibrillary tangles are bundles of twisted filaments found within neurons. 43 44  Alzheimer's Disease  In most people, symptoms of Alzheimer's disease One of the most common causes of appear after age 60. severe cognitive dysfunction in older persons  Alzheimer's disease usually causes a gradual decline in Alzheimer's disease is a progressive cognitive abilities, usually during a span of 7 to 10 disorder involving neural degeneration in the cortex that leads years. to a marked loss of memory and of  Nearly all brain functions, including the ability to carry on activities of daily living.  memory, Pathophysiology  movement, l The cause of the disease is not yet known,  anguage , but there is a progressive loss of ACh - producing neurons and their target  judgment, neurons.  behavior, and abstract thinking, are eventually affected. 45 46 Alzheimer disease  Clinical manifestations  Insidious and progressive loss of memory particularly to recent events , and emotional upset. 47