Cerebrovascular Disease: Time, Vessel, and Mechanism
Start with the clock and the vessel
Acute stroke items almost always hinge on two variables: time from last known well and whether a large vessel occlusion is present. Establish last known well first; wake-up strokes and unwitnessed onset are timed from when the patient was last seen normal.
Ischemic stroke. Intravenous thrombolysis is offered within 4.5 hours of onset after excluding hemorrhage and contraindications; blood pressure must be below 185/110 mmHg before treatment and kept below 180/105 afterward. Endovascular thrombectomy is standard for anterior circulation large vessel occlusion within 6 hours, and extends to 24 hours in selected patients with favorable imaging (small core, salvageable penumbra). Do not withhold thrombectomy just because a patient is outside the thrombolysis window. Minor stroke or high-risk transient ischemic attack warrants dual antiplatelet therapy for about 21 days, then single agent.
Mechanism drives prevention. Atrial fibrillation calls for anticoagulation, with DOACs preferred over warfarin except in mechanical valves and moderate-to-severe mitral stenosis. Carotid stenosis, dissection, and patent foramen ovale each have distinct management pathways.
Hemorrhage. For intracerebral hemorrhage, lower systolic pressure to about 140 mmHg, reverse anticoagulation promptly, and treat elevated intracranial pressure. Aneurysmal subarachnoid hemorrhage peaks with thunderclap headache, is complicated by vasospasm days 3 through 14, and nimodipine improves outcome. Lobar hemorrhage in an older patient suggests cerebral amyloid angiopathy.
Traps: a normal noncontrast CT very early does not exclude ischemia; posterior circulation strokes are frequently missed; lacunar syndromes by definition lack cortical signs such as aphasia or neglect.
Rule of thumb: the last known well time, not the time of discovery, governs every reperfusion decision.