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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?