Unit 5: Stroke Syndromes Flashcards
Stroke Statistics
- Stroke is the third leading cause of death in the United States. Over 160,000 people die each year from stroke in the United States.
- Stroke is a leading cause of serious long–term disability.
- About 700,000 strokes occur in the United States each year. About 500,000 of these are first or new strokes. About 200,000 occur in people who have already had a stroke before.
- Nearly three–quarters of all strokes occur in people over the age of 65. The risk of having a stroke more than doubles each decade after the age of 55.
- Strokes can—and do—occur at ANY age. Nearly one quarter of strokes occur in people under the age of 65.
- Stroke death rates are higher for African Americans than for whites, even at younger ages.
- According to the American Heart Association, stroke cost almost $57 billion in both direct and indirect costs in 2005
- It has been noted for several decades that the southeastern United States has the highest stroke mortality rates in the country. It is not completely clear what factors might contribute to the higher incidence of and mortality from stroke in this region.
Ischemic (Stroke Mechanisms)
80-85% of strokes
- Lack of blood flow to a portion of the brain.
- Blockage of bloodflow
Embolic (Stroke Mechanisms)
(source is usually cardiac related-A-fib or MI-has an abrupt onset)
-Common sites of occlusion: internal carotid or middle cerebral
Thrombic (Stroke Mechanisms)
(common in patients over 50 usually due to atherosclerosis—onset can be abrupt or slow)
-Common sites of occlusion: vertebral, basilar, middle cerebral; less common; anterior cerebral or posterior cerebral
Hemorrhagic
15-20% of strokes (Usually occur in younger patients)
- Weak part of vessel ruptures
- Intracerebral hemorrhage
- Subarachnoid hemorrhage
- Can be caused by: aneurysm, AV malformation or HTN, trauma to the head or a bleeding disorder.
- In general hemorrhagic strokes have better outcomes (since patients are typically younger)
Stroke Mortality
- Hemorrhagic strokes have a higher mortality rate than embolic or thrombic strokes (30%)
- Lowest mortality rate seen with smaller lacunar infarcts
- Bigger lesions have higher mortality than smaller lesions
- Higher risk of sustaining a subsequent stroke
Anterior Circulation
- Internal carotid arteries
- Anterior cerebral arteries
- Anterior communication artery l Middle cerebral arteries
- Posterior communicating arteries
Posterior Circulation
- Vertebral arteries
- Posterior spinal arteries l Anterior spinal artery
- Posterior inferior cerebellar arteries (PICA)
- Anterior inferior cerebellar arteries (AICA)
- Basilar artery
- Superior cerebellar arteries
- Posterior cerebral arteries
Cortical Stroke Syndromes
Most common that we will see post-stroke
- Middle Cerebral Artery
- Anterior Cerebral Artery
- Posterior Cerebral Artery
MCA (Clinical Syndromes of Three Cerebral Arteries)
Most common source of infarct -Superior division -Inferior division -Deep territory Proximal occlusions affect all 3 regions are called stem infarcts
MCA-Left superior & inferior divisions
MCA-Right superior & inferior divisions
MCA-Left deep territory & stem
MCA-Right deep territory & stem
ACA (Clinical Syndromes of Three Cerebral Arteries)
-UMN weakness & cortical-type sensory loss
affecting contralateral LE
Dominant ACA strokes-transcortical motor aphasia
-Variable frontal lobe dysfunction
Non-dominant ACA strokes-contralateral neglect
-Variable frontal lobe dysfunction