Stroke (Week 4--Ali)

Question 1

Definition of stroke

Answer 1

Permanent injury to brain or spinal cord of vascular origin (either reduced blood flow or bleedint into or around the brain or spinal cord)

1) Cerebral infarction
2) Intracerebral hemorrhage
3) Subarachnoid hemorrhage

Question 2

Transient ischemic attack

Answer 2

Transient episode of neurological dysfunction caused by focal brain, spinal cord or retinal ischemia, without acute infarction

Note: this tissue-based definition recently replaced prior, time-based (24 hour) definition

After TIA, 10x risk of ischemic stroke (risk highest in first 48 hours following TIA; 35% stroke risk within 3-5 years after TIA)

Question 3

Facts about stroke

Answer 3

Leading cause of adult disability in US

3rd leading cause of death in US

>5 million stroke survivors and 90% have deficit

Question 4

Pathogenesis of cerebrovascular disease

Answer 4

Ischemic stroke (83%): atherothrombotic (30%), cardioembolic (30%), lacunar (25%), other (10%), cryptogenic (5%)

Hemorrhagic stroke (17%): intracerebral hemorrhage (70%), SAH (30%)

Question 5

Stroke risk factors

Answer 5

Nonmodifiable: age, gender, race, heredity

Medical conditions: HTN, cardiac disease, a-fib, hyperlipidemia, DM, carotid stenosis, prior TIA or stroke

Behaviors: cigarette smoking, heavy alcohol use, physical inactivity

Question 6

Pathogenesis of brain infarction

Answer 6

1) Sudden interruption of cerebral blood supply
2) Alteration of brain metabolism (after 30 sec)
3) Cessation of neuronal function (after 1 min)
4) Formation of infarct (5 min - 10 hours)
5) Tissue necrosis and softening (days)
6) Replacement by fluid and gliosis (weeks - months)

Question 7

Ischemic penumbra

Answer 7

Area outside core infarct

Zone of salvageable tissue surrounding core infarct

Question 8

Anterior cerebral artery (ACA) syndrome

Answer 8

Contralateral leg weakness

Contralateral leg sensory loss

Bladder incontinence

Question 9

Middle cerebral artery (MCA) syndromes

Answer 9

Superior division: contralateral face and arm > leg weakness; contralateral face and arm > leg sensory loss; broca/nonfluent aphasia (left hemisphere); contralateral neglect (right hemisphere)

Inferior division: contralateral hemianopia, superior quadrantanopic; Wernicke/fluent aphasia (left hemisphere); contralateral neglect (right hemisphere)

Question 10

Posterior cerebral artery (PCA) syndrome

Answer 10

Contralateral hemanopia, quadrantanopia

Alexia (can’t read) without agraphia (left hemisphere)

Visual agnosias with bilateral PCA infarcts (visual object agnosia, prosopagnosia, simultagnosia, cortical blindness)

Question 11

Vertebrobasilar syndromes

Answer 11

Ataxia, vertigo, diplopia, dysarthria, dysphagia, bilateral weakness, bilateral sensory loss, crossed cranial and body signs

Question 12

Lacunar syndromes

Answer 12

Pure motor hemiparesis: isolated face, arm, leg weakness

Pure sensory stroke: isolated face, arm, leg sensory loss

Ataxic hemiparesis: homolateral ataxia and hemiparesis

Dysarthria clumsy hand syndrome

Question 13

Large artery atherothromboembolic stroke

Answer 13

Risk factors: age, HTN, DM, tobacco, hyperlipidemia, hx CAD, PAD

Clinical features: progressive deficits (frequently stepwise) in 50%, onset while asleep in 30-40%, preceeding TIAs in 40%

Question 14

Cardioembolic stroke

Answer 14

Risk factors: a-fib, sick sinus syndrome, rheumatic valvular disease, prosthetic cardiac valve, dilated cardiomyopathy

Clinical features: maximal deficits at onset in 80-90%, usually not onset while asleep, usually no preceding TIAs

Question 15

Sources of cardiogenic embolism

Answer 15

45% nonvalvular a-fib

15% acute MI

10% ventricular aneurysm

10% rheumatic heart disease

10% prosthetic cardiac valves

10% other

Question 16

Small vessel (lacunar) stroke

Answer 16

Risk factors: arteriosclerosis and atherosclerosis, age, HTN

Clinical features: progressive deficits in 45%, onset while asleep in 40-50%, preceding TIAs fairly common 20%

Small vessel symdromes cortical signs rare

Diagnosis: clinical, CT/MRI confirmation

Mortality low, 1%

Rate of recurrence 12% annual

Question 17

Intracerebral hemorrhage

Answer 17

Smoothly progressive deficits over 10-20 minutes

Onset while asleep uncommon 15%

Focal symptoms

Symptoms of raised intracranial pressure (headache, nausea/vomiting, decreased level of consciousness)

Question 18

Subarachnoid hemorrhage

Answer 18

Thunderclap headache

Usually no onset while asleep

Symptoms of raised intracranial pressure (headache, nausea/vomiting, decreased level of consciousness)

Focal symptoms uncommon

Diagnosis: CT, LP mandatory with clinical suspicion and normal CT (elevated CSF pressure and protein, large # RBCs, SAH has xanthochromic centrifuged supernatant and trauma doesn’t), angiography gold standard (if neg repeat in 2 weeks)

Question 19

Clinical grading of aneurysmal SAH

Answer 19

Grade I: normal LOC, no clinical features, yes surgical candidate

Grade II: normal LOC, HA/stiff neck, yes surgical candidate

Grade III: confused/drowsy, focal neuro deficits, yes surgical candidate

Grade IV: stupor, focal neuro deficits, not surgical candidate

Grade V: coma, decerebrate posturing, not surgical candidate

Question 20

Outcome after SAH

Answer 20

32% mortality from aneurysmal SAH (most in first few days)

Neurologic condition at arrival at hospital is most important determinant of outcome

Permanent disability (cognitive usually) in 50% of survivors

Better prognosis with ruptured AVMs compared to aneurysmal rupture (recovery in almost 90%)