CVA, TIA - Brain Attack Flashcards
What is a stroke?
infarct of brain tissue d/t lack of blood flow to a certain part of the brain
complete blockage is caused by a clot or by a hemorrhage
decreased blood flow is caused by a stenosed occluded or ruptured blood vessel feeding the brain
Stroke: RFs
HTN High Cholesterol DM Smoking Obesity (esp central) Age Cocaine and methamphetamines ETOH (daily) Hispanics, Native Americans, Asian Americans, and Black Americans AFib Previous TIA or CVA
Stroke: Pathophysiology
when there is a blockage or hemorrhage in a certain blood vessel, that area of the brain becomes ischemic
neurologic metabolism is altered in 30s, metabolism stops in 2 min, and cell death occurs in 5 min
when tissue becomes ischemic the body responds by causing cytotoxic edema in the surrounding tissue making perfusion even more difficult, increasing ICP
Stroke: Prevention of CVA/TIA
- decrease BP
- decrease cholesterol
- well controlled blood sugar
- stop smoking
- anti-platelet aggregation meds (ASA, plavix)
- anticoagulant for Afib
- decrease alcohol use
- control obesity
- increase exercise
identify and tx asymptomatic carotid stenosis
- carotid bruits & screen w/ u/s and doppler
- tx w/ ASA or other platelet anti-aggregate meds, statins
- if stenosis found a carotid endarterectomy will be done to improve cerebral flow
cerebral aneurysms: monitor, or tx w/ balloons, stents, coils
prevent cardiogenic emboli w/ tx of Afib; ASA. coumadin, xarelto, pradaxa
TIA: Definition and Sx
brief episode of neuro dysfunction caused by focal or retinal ischemia w/ symptoms typically lasting less than 1 hour and w/o evidence of acute infarction
typically all symptoms resolve w/in 24 hours, no residual effects
most common occur in carotid and vertebrobasilar arteries
Sx: numbness, weakness, paralysis, slurred speech, dizziness, confusion, aphasia, double vision, loss of half of visual field (hemianopia), loss of vision in one eye (amaurosis fugax)
TIA and the Future
Recognition is critical in these patients b/c TIAs increase the risk of strokes:
- 1/3 have no more TIA’s
- 1/3 have more TIA’s
- 1/3 progress to CVA
may be caused by an unstable plaque that occludes distal tissue
may be caused by a microemboli temporarily blocking blood flow
Types of CVA’s
ischemic: interruption of blood supply
- 87% of strokes
- damage is done only from lack of blood
hemorrhagic: rupture of blood vessel of abnormal vascular structure
- 13% of all stokes
- damage is done d/t lack of blood and pressure from bleeding
Ischemic Strokes: Causes
- thrombosis: clot forming locally
- embolism: embolus from somewhere else in the body
- systemic hypoperufsion: -general decrease in blood supply
- venous thrombosis: could dislodge and travel
Ischemic Stroke: Thrombosis
- clot form w/in vessel of brain which cuts off blood supply beyond the location of the clot
- usually forms d/t atherosclerosis
- occurs when BP is the lowest, usually
most common cause of CVA in elderly and middle age
Ischemic Stroke: Embolic
blockage of artery by an arterial embolus, a traveling particle or debris in the arterial bloodstream originating elsewhere (can be blood clot, fat, air, cancer cells, or bacteria)
RF: Afib, rheumatic fever, open heart surgery, ortho surgery, endocarditis
source must be identified
tend to occur during day, during periods of activity
if embolus is septic, the infection may extend beyond the vessel wall, leads to abscess which may develop into an aneurysm
can occur at any age
Ischemic Stroke: Hypoperfusion
reduction in blood flow to all parts of the body
-commonly caused d/t HF from cardiac arrest or arrhythmias
reduction in blood flow is global so all parts of the brain is affected
blood flow to these areas does not stop, but is decreased to the point where brain damage can occur
Hemorrhagic Stroke: Intracerebral
bleeding w/in the brain cause by a rupture of a vessel
very poor prognosis
often occur w/ activity, rapid onset of symptoms
RF: HTN, aneurysms, trauma, anticoagulant meds, thrombolytic drugs, thrombocytopenia, tumors, AV malformations
Sx: loss of consciousness, worst HA ever, vomiting, decreased LOC
extent of sx depends on amount, location, and duration of bleeding
Hemorrhagic Strokes: SAH (subarachnoid hemorrhage)
bleeding into the cerebrospinal fluid space between the arachnoid and pia mater membranes on the surface of the brain
often caused by rupture of cerebral aneurysm, trauma, or cocaine
increased incidence w/ age and higher in women
“silent killer” as there are few warning signs
worst HA ever
poor prognosis
Expressive Aphasia
difficulty speaking or writing
Wernicke Aphasia
can’t understand, but can speak
