Cerebral Vascular Accident (CVA) (Answered)

Cerebral Vascular Accident (CVA) (Answered) Define CVA Sudden onset of neurologic signs and symptoms resulting from disturbance of blood supply to brain Transient ischemic attack (TIA) Temporary interruption in blood supply to brain; symptoms resolve in 24 hours State the etiology of a CVA 1. Ischemia (87%) a. Thrombosis - Formation of blood clot within cerebral, carotid, or vertebral arteries - Most often caused by atherosclerosis b. Embolism - Blood clot forms elsewhere and travels to cerebral, carotid or vertebra arteries - Most often caused by atrial fibrillation, myocardial infarction, or cardiac valve disease c. Low system perfusion - Heart failure - Significant blood loss 2. Cerebral hemorrhage - Bleeding into brain - Wall of vessel weakened by aneurysm - Progressive dilation and eventual burst of arteriovenous malformation (AVM) - Most often caused by hypertension, aging, trauma List the risk factors of CVA 1. Hypertension 2. Diabetes mellitus 3. Hyperlipidemia 4. Heart arrhythmias 5. Smoking/tobacco use 6. Heavy alcohol use 7. Cocaine/amphetamine use 8. Coronary artery disease 9. Chronic heart failure (CHF) 10. Peripheral arterial disease 11. Chronic kidney disease 12. Sleep apnea 13. Early menopause 14. Use of estrogen 15. Obesity 16. Diminished physical activity Explain the pathophysiology of CVA 1. Cerebral edema a. Most frequent cause of death from infarction b. Causes - Tissue necrosis - Rupture of cell membranes - Movement of fluid from blood vessels to interstitial spaces c. Results in increased intracranial pressure 2. Chemical irritation from hemorrhagic stroke causes vasospasm 3. Ischemic cascade: series of events that damage neurons - Inability of brain cells to produce energy - Formation of free radicals - Release of nitric oxide and cytokine-increased inflammation Frontal lobe 1. Primary motor cortex 2. Cognitive function 3. Motor function of speech (Broca's area) Parietal lobe 1. Primary somatosensory cortex 2. Perception (attach meaning to sensory information) Temporal lobe 1. Auditory cortex 2. Meaning of speech sounds (Wernicke's are) 3. Memory Occipital lobe 1. Primary visual cortex Cerebral circulation 1. All arteries to brain arise from aortic arch 2. Anterior circulation 3. Posterior circulation 4. Posterior communicating artery connects posterior cerebral artery to internal carotid artery Anterior circulation 1. Common right and left carotid arteries branch to internal carotids - Supply frontal lobe - Supply parietal lobe - Supply portion of temporal and occipital lobes - Supply basal ganglia - Supply optic nerves and retinas 2. Anterior communicating artery connects right and left internal carotid arteries 3. Middle cerebral artery - Largest - Supply lateral surface of brain - Supply deep portions of frontal and parietal lobes - Supply posterior part of internal capsule - Supply basal ganglia 4. Anterior cerebral artery: supply superior border of frontal and parietal lobes Posterior circulation 1. Subclavian artery branches into right and left vertebral arteries - Go through transverse foramen in cervical spine - Supply medulla and upper spinal cord 2. Vertebral arteries fuse to form basilar artery-supply pons and cerebellum 3. Basilar artery divides into right and left posterior cerebral arteries - Supplies midbrain - Supplies occipital and temporal lobes Anterior cerebral artery syndrome 1. Contralateral weakness, LE worse than UE 2. Contralateral sensory impairment, LE worse than UE 3. Slow movement 4. Ideomotor apraxia: inability to perform a task upon command, but can do it automatically 5. Ideational apraxia: inability to perform a task either automatically or on command 6. Incontinence Middle cerebral artery syndrome 1. Most common 2. Contralateral weakness, UE worse than LE 3. Contralateral ataxia 4. Aphasia: acquired communication disorder in individuals previously capable of using language appropriately - Receptive (Wernicke's) aphasia: inability to comprehend language; fluent speech with frequent word substitutions - Expressive (Broca's) aphasia: inability to create language, with intact comprehension - Global aphasia: inability to comprehend and create language Perceptual deficits of middle cerebral artery syndrome (perceptual parietal) 1. Homonymous hemianopsia 2. Unilateral neglect - Inability to register and integrate stimuli and perceptions from one side of the body and the environment on that side - Not due to sensory loss or visual field cut - Most often affects left side 3. Figure-ground discrimination: inability to distinguish and object from its background 4. Apraxia 5. Somatoagnosia - Lack of awareness of body structure - Lack of awareness of relationship of body parts to oneself or others - May be caused or made worse by proprioceptive deficits 6. Spatial relations: inability to perceive the relationship of one object in space to another object or to oneself 7. Depth perception: inaccurate judgement of direction, distance, and depth 8. Homonymous hemianopsia - Contralateral visual field cut - Loss of outer half of visual field from one eye and inner half of visual field in the other eye - Patient is unaware of field cut, and does not automatically compensate by turning head Posterior cerebral artery syndrome 1. Contralateral hemiplegia 2. Contralateral sensory loss 3. Thalamic pain syndrome: intolerable burning pain and sensory perseveration 4. Homonymous hemianopsia 6. Cortical blindness 7. Memory loss Vertebrobasilar artery syndrome 1. Contralateral paralysis 2. Contralateral sensory loss 3. Double vision 4. Dysphagia: difficulty swallowing 5. Dysarthria: difficulty with motor production of speech due to weakness and incoordination of speech musculature 6. Ataxia 7. Deafness 8. Vertigo 9. Locked-in syndrome - Quadriplegia - Lack of speech - Intact cognition