Ischaemic Stroke
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Direct answer
Ischaemic stroke — sudden focal neurological deficit from vascular occlusion — accounts for the large majority of all strokes. Immediate non-contrast CT of the head excludes haemorrhage and opens the reperfusion pathway: intravenous thrombolysis with alteplase 0.9 mg per kg (maximum 90 mg, 10 per cent as bolus) within 4.5 hours of onset, and mechanical thrombectomy for anterior-circulation large-vessel occlusion up to 6 hours, extended to 24 hours in selected patients with imaging mismatch. Aspirin within 24 to 48 hours, stroke-unit care, and early secondary prevention complete the management.
What you must remember
- Recognition: sudden face-arm weakness, speech disturbance or visual and cerebellar deficits; check glucose first to exclude mimics — hypoglycaemia, seizure with Todd's paresis, migraine, functional weakness.
- Non-contrast CT is the first investigation in every acute stroke; it excludes haemorrhage and may show early ischaemic signs such as a hyperdense vessel or lost grey-white differentiation.
- IV thrombolysis: alteplase 0.9 mg per kg, maximum 90 mg, 10 per cent bolus then infusion over one hour, within 4.5 hours; tenecteplase as a single bolus is an accepted alternative.
- Contraindications: intracranial haemorrhage, recent intracranial surgery or head trauma, active bleeding, platelets below 100,000, INR above 1.7, a direct oral anticoagulant within 48 hours, and blood pressure above 185/110 mmHg that cannot be lowered.
- Thrombectomy: for internal carotid or proximal middle cerebral artery occlusion within 6 hours; up to 24 hours in selected patients with favourable perfusion mismatch.
- Blood pressure: do not lower unless above 220/120 mmHg (without reperfusion) or above 185/110 mmHg before thrombolysis — maintain permissive hypertension for penumbral perfusion.
- General care and prevention: swallow assessment before oral intake, euglycaemia, normothermia, DVT prophylaxis, early rehabilitation, decompressive hemicraniectomy for malignant MCA infarction; then high-intensity statin, antiplatelet therapy (short-term dual for minor stroke or high-risk TIA), timed anticoagulation for atrial fibrillation, and risk factor control.
A thrombolysis decision, minute by minute
A 64-year-old develops right hemiparesis and aphasia at 9:15 am; she reaches the emergency department at 10:40 am, last-seen-well certain. Glucose first — 130 mg/dL, excluding hypoglycaemia — then non-contrast CT immediately, because the haemorrhage question is settled only by imaging and thrombolysing a haemorrhagic stroke is the catastrophic error. The CT shows no blood and a subtle hyperdense left middle cerebral artery. Time from onset: 85 minutes, inside the 4.5-hour window. Run the contraindication list: no recent intracranial surgery or head trauma, no active bleeding, platelets above 100,000, no anticoagulants, and blood pressure — 198/104 — needs labetalol below 185/110 before the needle. Alteplase 0.9 mg per kg, maximum 90 mg, 10 per cent as bolus and the rest over one hour (tenecteplase as a single bolus is an accepted alternative); aspirin waits 24 hours, then starts within the 24-to-48-hour rule. Had CT angiography shown a proximal middle cerebral artery or internal carotid occlusion, thrombectomy enters — within 6 hours standard, to 24 hours with perfusion mismatch — and neither therapy excuses stroke-unit care: swallow assessment before oral intake, euglycaemia, normothermia, DVT prophylaxis, early rehabilitation, decompressive hemicraniectomy for malignant MCA infarction. After the acute phase, the aetiological work-up decides prevention:
Where students slip
Two blood pressure thresholds get interchanged: 185/110 belongs to the thrombolysis candidate, 220/120 to the patient managed without reperfusion — and "treat the hypertension urgently" is the reflex the permissive-hypertension principle overrides, because pressure perfuses the penumbra. The dose arithmetic is the second error: 10 per cent bolus of 0.9 mg per kg with a 90 mg ceiling. TIA complacency is the third: resolving symptoms still carry early stroke risk demanding urgent work-up. Territory questions pair the deficit with the vessel and then the prevention — cardioembolic atrial fibrillation above all.
Frequently asked questions
What is the time window and dose for IV thrombolysis?
Within 4.5 hours of onset, alteplase 0.9 mg per kg up to 90 mg — 10 per cent as a bolus, the remainder over one hour.
Why must a non-contrast CT precede thrombolysis?
To exclude intracranial haemorrhage and large established infarction, both absolute contraindications; CT is the fastest discriminator between ischaemic and haemorrhagic stroke.
When is mechanical thrombectomy indicated?
For anterior-circulation large-vessel occlusion within 6 hours, and up to 24 hours in selected patients when perfusion imaging shows salvageable brain.
How is blood pressure managed in acute ischaemic stroke?
Permissive hypertension is the rule; treat only above 220/120 mmHg without reperfusion, or above 185/110 mmHg before and during thrombolysis.
When is aspirin started?
Within 24 to 48 hours, but withheld for at least 24 hours after thrombolysis; a brief dual antiplatelet course follows minor stroke or high-risk TIA.
Which patients need anticoagulation rather than antiplatelets?
Those with cardioembolic sources — chiefly atrial fibrillation, mechanical valves or intracardiac thrombus — with timing individualised to infarct size.