Unit 5: Stroke Syndromes Flashcards
(28 cards)
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
PCA (Clinical Syndromes of Three Cerebral Arteries)
-Contralateral homoymous hemianopia (visual deficit)
-If smaller, penetrating vessels are involved- contralateral sensory loss, contralateral hemiparesis, (damage to thalamus or posterior limb of internal capsule-larger infarcts)
-Left occipital cortex: Alexia without agraphia
-Left thalamus & internal capsule: Aphasia
Occlusion of ICA or drop in BP with a patient with carotid stenosis can cause ACA-MCA watershed infarct (Both are fed by carotid)
-Dominant hemisphere: Transcortical
aphasia syndromes
-MCA-PCA disturbances of higher order visual processing
Watershed Infarcts
-Watershed zones: When blood supply to 2 adjacent cerebral arteries is compromised, regions between 2 vessels are most susceptible to ischemia & infarction
Watershed Infarcts (image)
MCA and ACA Watershed Infarcts
Symptoms include: proximal arm & leg weakness
Brainstem Strokes
Usually a worse prognosis for survival or recovery
- May involve coma, lesions of cranial nerves, lesions of descending motor or ascending sensory pathways
- Prognosis will depend on the location and size of lesion and amount of collateral blood flow and early medical care
Vertebral-Basilar Artery Syndromes: Brainstem Strokes
Characterized by “the 4 D’s with crossed findings” The 4 D’s are: -Diplopia -Dysarthria -Dysphagia -Dizziness Other signs: -Contralateral weakness -Contralateral sensory loss -Cerebellar signs
Stroke Syndromes: AICA/Lateral pontine syndrome or Marie-Foix syndrome
Damage to AICA and the basilar artery
- Ataxia of UE and LE: Damage to cerebellar tracts
- Contralateral weakness: Damage to the corticospinal tracts
- Contralateral sensory loss (pain & temperature): Damage to spinothalamic tract
Basilar Artery Syndromes
- Locked In Syndrome
- Ventral Pontine Syndrome/Raymond Syndrome
- Ventral Pontine Syndrome/Millard-Gubler Syndrome
Locked In Syndrome (Basilar Artery Syndromes)
- Bilateral weakness of UE, LE and face: Corticospinal tract damage
- Lateral gaze weakness: Bilateral fascicles of CN 6
- Dysarthria: Bilateral corticobulbar tract damage
