Cerebrovascular disorders: ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, cerebral venous thrombosis
Cerebrovascular disease is the highest-yield emergency domain. Questions test time windows, imaging selection for reperfusion, blood pressure thresholds, anticoagulation reversal, and the distinct management of subarachnoid haemorrhage and cerebral venous thrombosis.
Ischaemic stroke
Sudden focal deficit - exclude hypoglycaemia first. Non-contrast CT excludes haemorrhage; early ischaemic signs (loss of the insular ribbon, hyperdense MCA, sulcal effacement) are subtle. Intravenous alteplase 0.9 mg/kg (maximum 90 mg, 10% as a bolus, remainder over one hour) is given within 4.5 hours; tenecteplase 0.25 mg/kg is an accepted alternative. Blood pressure must be below 185/110 mmHg before lysis and kept below 180/105 afterwards. Mechanical thrombectomy applies to large vessel occlusion within 6 hours, and up to 24 hours in selected patients with a small core and imaging mismatch. Aspirin starts after 24 hours post-lysis, or within 48 hours if no lysis; complete a swallowing screen.
Haemorrhage
Intracerebral haemorrhage: control systolic pressure towards about 140 mmHg, reverse anticoagulation immediately (vitamin K plus prothrombin complex concentrate for warfarin, idarucizumab for dabigatran, protamine for heparin), and obtain a neurosurgical opinion for cerebellar haematoma over 3 cm or hydrocephalus. Subarachnoid haemorrhage: thunderclap onset; CT within 6 hours is highly sensitive, otherwise lumbar puncture at 12 hours or later for xanthochromia; give nimodipine 60 mg every 4 hours for 21 days and secure the aneurysm by coiling or clipping.
Cerebral venous thrombosis
Headache, seizures, focal deficit, papilloedema, often with a prothrombotic state. Anticoagulate with heparin or low-molecular-weight heparin even when there is haemorrhagic infarction, then transition to oral anticoagulation for 3-12 months depending on the cause.
Worked example
A 68-year-old arrives at 3 hours with global aphasia, right hemiplegia and NIHSS 18. CT shows no blood, ASPECTS 9, CTA shows a left M1 occlusion, and perfusion shows a small core with a large penumbra. Actions: activate thrombectomy, give thrombolysis if blood pressure, glucose and contraindications permit, admit to a stroke unit, and monitor for haemorrhagic transformation and malignant oedema.
Traps
Do not lower blood pressure aggressively in ischaemic stroke and do not give steroids. A normal early CT does not exclude infarction. Wake-up stroke is selected by imaging, not by the clock. Anticoagulation is not contraindicated in venous thrombosis with haemorrhagic infarction. Posterior circulation deficits (diplopia, vertigo, ataxia) are easily dismissed as labyrinthitis.