Neurologic Function Part 2
Terms
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- Stroke/Cerebrovascular Accident
- The abrupt or rapid onset of neurological deficits resulting from decreased oxygen to the brain.
- what % of 1st strokes are fatal?
- 25%
- What % of 1st strokes result in moderate to severe disabilities.
- 28%
- What is the key for strokes?
- prevention
- What are nonreversible risk factors for stroke?
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Gender - male higher
Age - older higher
Race - blacks higher
Heredity - What are reversible risk factors for stroke?
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Hypertension is most significant
Cardiac disease
diabetes
blood lipid abnormalities
obesity
abnormal antibodies - autoimmune problem could be cause. - What are some substances that are risk factors for stroke?
-
Alcohol use
smoking
oral contraceptives (hormones)
substance abuse (cocaine) - What are extracranial factors affecting cerebral blood flow?
-
Systemic blood pressure
Cardiac output
Blood viscosity - How is systemic blood pressure an extracranial factor affecting blood flow?
- Map < 50 or above 150 autoregulation is effected. Leads to ischemic damage from decreased cerebral blood flow.
- How does cardiac output affect cerebral blood flow?
- When it is decreased by 1/3 it effects cerebral blood flow.
- How does blood viscosity affect cerebral blood flow?
- Polycythemia vera > COPD pts.; dehydration.
- What are intracranial factors affecting cerebral blood flow?
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Metabolic factors
Blood vessel condition
Intracranial pressure - What metabolic factors affect cerebral blood flow?
- Decreased PO2, increased PCO2, increased HCO3 (?)
- What blood vessel condition affects cerebral blood flow?
- AV malformation, aneurysms, atherosclerosis
- How does ICP affect cerebral blood flow?
- IICP increases pressure on blood vessels - blood doesn't flow freely > ischemia.
- What are the 4 basic types of strokes?
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Thrombosis
Embolism
Intracerebral hemorrhage
Subarachnoid hemmorrhage - Thrombosis defined:
- formation of clot in brain which blocks the artery > ischemia.
- Describe what happens with thrombosis formation:
- Clot forms > decrease perfussion from clot down > ischemia, necrosis, inflammatory response, inflammation increases > more pressure on tissue.
- What is the most common type of stroke?
- thrombosis - 55-65%
- What physical conditions is thrombosis associated with?
- diabetes and hypertension
- When do thrombosis clots occur usually?
- during periods of rest when everything slows down.
- What is a warning sign of a thrombosis?
- TIA
- Which arteries are usually effected by thrombosis?
- interior middle cerebral arteries.
- What is an embolism?
- Clot that floats into area from outside brain and blocks artery. Ischemic damage occurs.
- what are some characteristics of emboli?
- Beyond lodging get same responses as above. Occur suddenly, not related to activity.
- What is a warning sign of emboli?
- TIA
- What are some causes of emboli?
- Cardiac disease (chronic A Fib; Endocarditis after acute MI; valvular disease)or atherosclerotic disease in carotid arteries.
- Will emboli reoccur?
- Yes, if you don't treat underlying cause.
- Intracerebral hemmorrhage...
- bleeding into the brain with hemorrhagic damage,
- What causes the damage in an intracerebral hemorrhage?
- pressure > ischemia, etc. and the results of the body to clean up the area.
- What are predisposing factors to intracerebral hemorrhage?
-
HTN, atherosclerosis > vessels rupture, blood goes into brain > hematoma.
Bleeding into brainstem. - Subarachnoid hemorrhage...
- Bleeding into to subarachnoid space due to rupture of intracranial aneurysm or AVM. May also follow head trauma.
- Is subarachnoid hemorrhage related to activity?
- NO
- What is the 1st sign of subarachnoid hemorrhage?
- head ache > blood on meninges > sudden > rupture.
- What is the prognosis of subarachnoid hemorrhage?
- Poor
- Why is management of subarachnoid hemorrhage difficult?
- Because of vasospasms.
- What does temporal development mean in reference to strokes?
- Strokes typically progress through stages - develop over time.
- What does TIA stand for?
- Transient Ischemic Attack
- What is a TIA?
- brief episode of neurological deficits with no apparent residual damage. Episode last < 24 hours.
- What is considered to be the cause of TIA?
- vasospasms or microemboli which resolve.
- What is a Reversible Ischemic Neurological Deficit (RIND)?
- a neurological deficit which occurs suddenly and lasts > 24 hours but leaves no apparent residual effects.
- How long does the deficit caused by RIND last?
- may last several weeks but usually lasts < 1 week.
- Is RIND considered a warning like TIA?
- yes
- What tests will show cerebral damage even if effects not apparent?
- CT or MRI
- What is stroke in evolution?
- refers to the stroke in which deficits progress over a period of hours or days.
- What is a completed stroke?
- Deficits remain unchanged for 3 days. At this point aggressive rehabilitation begins unless stroke was due to ruptured aneurysm.
- What do the clinical manifestations of strokes depend on?
- Location, size of infarct and whether or not there is collateral circulation.
- What does the Circle of Willis contain?
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2 vertebral arteries
2 carotid arteries - What does the Anterior Cerebral Artery supply?
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The medial portion of brain (core)
Limbic system
RAS
Memory
Sensory Speech
Lower body - sensory, motor - What does the Middle Cerebral artery supply?
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Surface of brain
Hearing
Judgement, rational thought
Motor speech
Upper body - sensory, motor - What does the Posterior Cerebral artery supply?
-
cerebellum
brainstem - What are neuromuscular symptoms the result of:
- destruction of motor pathways in pyrimidal tract with loss of skilled voluntary movement.
- What is the result of right hemisphere damage?
- Left sided hemiplegia (paralysis)/paresis (weakness.
- Are upper and lower extremities affected to the same degree?
- No, can be to different degrees.
- When referring to hemi-, you are dividing the body into
- Right and left
- When referring to para-, you are dividing the body into
- upper and lower
- What is stroke in revolution?
- refers to the stroke in which deficits progress over a period of hours or days.