Stroke Flashcards
Describe a stroke
A stroke occurs when there is ischemia (inadequate BF) to a part of the brain that results in the death of brain cells.
Synonyms: CVA (cerebral vascular accident, cerebral ischemia)
Strokes are the ___ leading cause of death in Canada
3rd
What % of cardiac output goes to the cerebral BF?
20%
How long after full neurological BF occlusion does cellular death occur?
after 5 minutes
Describe cerebral autoregulation
Changes in diameter of cerebral BVs in response to changes in BP so the brain BP stays constant.
CO would have to be reduced by a third to reduce cerebral BF due to cerebral autoregulation shunting BF to the brain.
Compensating function of the Circle of Willis
If a blockage stops BF in a connected artery, the change in BP causes blood to flow forward or backward in the circle of Willis to compensate
What is a vasovagal response?
When BP temporarily drops causing pallor and fainting due to overactivity of vagus nerve.
What gender experiences more strokes?
Men
What gender dies more frequently due to strokes?
Women
What races have a higher risk factor for strokes?
African Americans, African-Canadians
What is one modifiable risk factor specifically in women for strokes?
Oral contraceptives and HRT (hormone replacement theory - used in menopause to give estrogen)
3 Contributing factors to strokes
- Hypertension (risk for atherosclerosis, thrombotic stroke, aneurysms)
- Diabetes (macrovascular complications)
- CAD (pooling blood from atrial fib can cause clots)
Describe Thrombosis
- more common
- platelet clot aggregation that forms, stays, and can eventually block vessel
- slower symptom onset
Describe embolism
- clot that develops, travels, and causes blockage somewhere else in the body
Describe hemorrhage
- breaking the vessel wall
- often atherosclerotic rupture
2 Types of strokes and their %s
- Ischemic Strokes (85%)
- Hemorrhagic Strokes (15%) POORER PROGNOSIS
3 types of Ischemic strokes and which is more common
- TIA
- Thrombotic (more common)
- Embolic (less common)
2 types of hemorrhagic strokes and which is more common
- Intracerebral (more common)
- Subarachnoid (less common)