Transient Ischemic Attack

Ischemic stroke is sudden focal neurologic deficit from arterial occlusion confirmed by infarction on neuroimaging. Diagnosis relies on urgent noncontrast head CT to exclude hemorrhage; treatment is IV alteplase within 4.5 hours and mechanical thrombectomy for large-vessel occlusion within an extended window, followed by antiplatelet therapy and risk-factor control.

Antiplatelet agents block platelet activation and aggregation to prevent arterial thrombosis. Aspirin irreversibly inhibits cyclooxygenase-1, and P2Y12 inhibitors such as clopidogrel, ticagrelor, and prasugrel block adenosine diphosphate-driven platelet activation. Aspirin 81 mg daily anchors secondary prevention, and dual antiplatelet therapy with aspirin plus a P2Y12 inhibitor is first-line after acute coronary syndrome or coronary stenting.

Carotid artery stenosis is atherosclerotic narrowing of the extracranial internal carotid artery that raises ischemic stroke risk, graded by percent luminal narrowing on duplex ultrasound. Symptomatic stenosis of at least 50% warrants urgent revascularization; asymptomatic stenosis under 80% is managed with best medical therapy alone, including a high-intensity statin and antiplatelet agent.

Atrial fibrillation is a supraventricular tachyarrhythmia with disorganized atrial activation and an irregularly irregular ventricular response, the most common sustained arrhythmia and a major cause of stroke. Diagnosis is by ECG showing no discrete P waves with irregular RR intervals, and management addresses rate or rhythm control, stroke prevention by CHA2DS2-VASc-guided anticoagulation, and the underlying cause.

Small subcortical infarct, under 1.5 cm, from occlusion of a single penetrating artery, most often caused by hypertensive lipohyalinosis, producing one of five classic pure motor, pure sensory, ataxic hemiparesis, dysarthria-clumsy hand, or mixed sensorimotor syndromes without cortical signs, diagnosed by MRI and managed with the standard acute stroke pathway plus aggressive antiplatelet, statin, and blood pressure secondary prevention.

Aphasia is an acquired disorder of language production and/or comprehension from a dominant-hemisphere lesion, most commonly acute ischemic stroke; a bedside exam of fluency, comprehension, and repetition localizes the syndrome and drives the emergent stroke workup and thrombolysis/thrombectomy decision.

Migraine is a primary episodic headache disorder diagnosed by ICHD-3 clinical criteria (recurrent attacks, 4-72 hours, pulsatile/unilateral pain with nausea or photophobia/phonophobia). First-line acute treatment is an NSAID or oral triptan started early in the attack; prevention with a beta-blocker, topiramate, or CGRP-targeted therapy is added once attacks are frequent or disabling.

Hypoglycemia is a plasma glucose below 70 mg/dL, most often a complication of insulin or sulfonylurea therapy for diabetes, and in a person without diabetes it requires a Whipple triad-based evaluation for insulinoma or another endogenous cause. An alert patient is treated with 15 to 20 g of fast-acting oral carbohydrate, while a patient unable to swallow safely receives intramuscular glucagon 1 mg or intravenous dextrose 50% 25 g.

Essential (primary) hypertension is chronically elevated blood pressure without an identifiable secondary cause, the overwhelming majority of hypertension. It is a leading modifiable driver of stroke, heart failure, and kidney disease, and management combines lifestyle change with staged pharmacotherapy to a target usually below 130/80 mmHg.