Acute Ischemic Stroke

• Stroke ranks third after ischemic heart disease as a cause of death worldwide.

• 80% of strokes are caused by focal cerebral ischemia due to arterial occlusion. The remaining 20% are caused by hemorrhages.

• Cerebral infarction cannot be distinguished with certainty from intracerebral hemorrhage on the basis of symptoms and signs alone.

Acute Ischemic Stroke - Diagnosis• Sudden onset of a focal neurologic deficit, though some

patients have a gradual progression of symptoms. • Consciousness is generally normal or slightly impaired,

except in posterior circulation infarcts.

• Signs and symptoms include: • Sudden weakness or numbness.• Sudden confusion.• Trouble speaking or understanding.• Visual loss in one or both eyes.• Sudden trouble walking.• Dizziness and loss of balance or coordination.• Sudden severe headache with no known cause.

Strokes

Large vessel

Ischemic

Hemorrhagic

Small vessel

Intracranial hemorrhages

Intracerebral Subarachnoid Subdural

Call Neurosurgeon

Ischemic strokes – Large vessels

Anterior cerebral

Posterior circulation

Anterior circulation (carotids)

Middle cerebral

Posterior cerebral Vertebro-basilar

Ischemic strokes – Small vessels

Lacunar Syndromes• Pure motor

(mouth=arm=leg)• Pure sensory• Mixed motor-sensor• Dysarthria & clumsy

hand• Atactic hemiparetic

Acute Ischemic Stroke - Etiology

Consider also: • Hypo-perfusion• Carotid-artery dissection - ptosis and miosis contralateral to the

deficit.• Infective endocarditis - fever and a cardiac murmur.• Giant-cell arteritis - headache and an elevated erythrocyte

sedimentation rate.

AtherosclerosisProximal EmbolismEtiology

Lacunar syndrome, progressive over hours

Major vessels syndrome, hyperacute

Presentation

Small VesselLarge vessel

Laboratory tests

• Glucose level (hypoglycemia may cause stroke-like focal neurologic deficits ).

• Complete blood count.• Basic biochemistry.• PT & PTT.• Electrocardiogram (Atrial fibrillation? Acute

MI?).

CT in acute stroke

CT - Not sensitive in the first hours but is performed to exclude bleeding

CT angiography -demonstrates the integrity of the large vessels

AtherosclerosisProximal EmbolismEtiology

CT without contrastCT angiographyImaging in ER

Lacunar syndrome, progressive over hours

Major vessels syndrome, hyperacute

Presentation

Small VesselLarge vessel

Early Reperfusion - Logic

• Initially after arterial occlusion, a central core of very low perfusion is surrounded by ischemic penumbra - an area of dysfunction caused by metabolic and ionic disturbances but in which structural integrity is preserved.

• The penumbra will eventually be incorporated into the infarct if reperfusion is not achieved.

Ischemic penumbra

MRI Perfusion/Diffusion mismatch represents salvageable brain tissue

Perfusion Diffusion

IV Thrombolysis

• Recombinant Tissue Plasminogen Activator (rt-PA) can be used up to 3 hours after the onset of symptoms (the last time the patient was observed to be normal).

• Among patients treated with rt-PA, 31-50% had a favorable functional outcome at 3 months (20-38% with placebo); mortality rates were similar in the two groups.

• Symptomatic intracranial hemorrhage occurred in 6.4% of patients treated with intravenous rt-PA and in 0.6% of controls.

Invasive Reperfusion Methods• In occlusion of major blood vessel1. Intra-arterial thrombolysis –

Up to 6 hours in the anterior circulation.

Up to 24 hours in the posterior circulation.

2. Mechanical thrombectomy –Up to 8 hours.

CT without contrastCT angiographyImaging in ER

AtherosclerosisProximal EmbolismEtiology

Intravenous thrombolysis

Intra-arterial thrombolysis

Immediate Intervention

Lacunar syndrome, progressive over hours

Major vessels syndrome, hyperacute

Presentation

Small VesselLarge vessel

Conservative Therapy

• Hypertension – reduce if higher than 160 systolic with β-blocker, ACE inhibitor or Thiazide.

• Give Aspirin / Plavix.• Keep normal glucose serum level.• Reduce fever if more than 37.5.

• No role for anti-coagulant in acute ischemic stroke .

Intravenous thrombolysis

Intra-arterial thrombolysis

Immediate Intervention

CT without contrastCT angiographyImaging in ER

AtherosclerosisProximal EmbolismEtiology

Look for vascular risk factors

Look for embolic source

Evaluation

Lacunar syndrome, progressive over hours

Major vessels syndrome, hyperacute

Presentation

Small VesselLarge vessel

When symptoms started?