Stroke — Causes, Symptoms, FAST Recognition & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

A stroke occurs when blood supply to part of the brain is suddenly interrupted (ischaemic stroke) or when a blood vessel ruptures causing bleeding into or around the brain (haemorrhagic stroke). Ischaemic stroke accounts for approximately 85% of all strokes; haemorrhagic stroke for 15%. Stroke is the second leading cause of death globally (5.5 million deaths annually) and the leading cause of acquired disability in adults. Approximately 15 million people suffer a stroke worldwide each year. Transient ischaemic attack (TIA) — often called a 'mini-stroke' — produces the same symptoms but resolves completely within 24 hours, leaving no permanent deficit; it carries a 10-15% risk of completed stroke within 3 months (highest in first 48 hours) and requires the same urgent evaluation as a completed stroke. Every minute of ischaemic stroke without treatment, approximately 1.9 million neurons are irreversibly lost — hence the phrase 'time is brain.'

Ischaemic stroke causes: cardioembolic (atrial fibrillation — causes 20% of all ischaemic strokes; embolus from AF-related left atrial thrombus), large artery atherosclerosis (carotid stenosis, intracranial atherosclerosis), small vessel disease (lacunar infarcts — hypertension-related), and cryptogenic (unknown, up to 25%). Haemorrhagic stroke: intracerebral haemorrhage (most common — hypertension-related in deep locations; cerebral amyloid angiopathy in lobar haemorrhage in elderly), and subarachnoid haemorrhage (ruptured saccular aneurysm — 80%). Modifiable risk factors: hypertension (most important — responsible for 50% of strokes), atrial fibrillation, diabetes mellitus, dyslipidaemia, smoking (doubles stroke risk), excessive alcohol, obesity, physical inactivity, obstructive sleep apnoea, and oral contraceptive pill (especially with migraine with aura). Non-modifiable: age (risk doubles every decade over 55), male sex, Black and South Asian ethnicity (higher hypertension and stroke rates).

The FAST test identifies the most common stroke features: Face drooping (one side of the face drooping or numb — ask to smile); Arm weakness (one arm weak or numb — can they raise both arms?); Speech difficulty (slurred, confused, or unable to speak or understand); Time to call emergency services immediately. Additional stroke symptoms: sudden severe headache described as the 'worst headache of my life' (subarachnoid haemorrhage until proven otherwise); sudden loss of vision in one or both eyes; sudden dizziness, loss of balance, or coordination; and sudden confusion or altered consciousness. Posterior circulation stroke (cerebellum, brainstem) presents with diplopia (double vision), ataxia (coordination failure), vertigo, dysphagia, and dysarthria. Symptoms are typically of sudden onset and maximal at onset for embolic strokes. Migraine aura, hypoglycaemia, Todd's paresis after seizure, and brain tumours can mimic stroke ('stroke mimic') — rapid clinical assessment distinguishes these.

Non-contrast CT brain is the first-line emergency investigation — rapidly performed, available 24/7, and sufficient to exclude haemorrhagic stroke (the most critical immediate decision before thrombolysis). CT shows blood immediately in haemorrhagic stroke; early ischaemic changes may be subtle in first hours. CT angiography (CTA) of head and neck vessels identifies large vessel occlusion amenable to mechanical thrombectomy and evaluates carotid disease. MRI brain with DWI (diffusion-weighted imaging) is more sensitive than CT for acute ischaemia (detects infarct within minutes) and posterior fossa strokes — performed when CT negative but symptoms persist, or to characterise lesion extent. Cardiac evaluation: 12-lead ECG (immediate AF detection), echocardiography, and prolonged cardiac monitoring (implantable loop recorder for 2-3 years in cryptogenic stroke to detect paroxysmal AF). Blood tests: glucose (exclude hypoglycaemia), coagulation screen, lipid profile, FBC, and thrombophilia screen in young patients.

Acute ischaemic stroke: IV alteplase (0.9 mg/kg, maximum 90 mg) within 4.5 hours of stroke onset restores blood flow by dissolving the clot — reduces disability and improves independence at 3 months. Mechanical thrombectomy — catheter-based removal of the clot from a large vessel occlusion (internal carotid artery, M1/M2 MCA, basilar artery) — is the most effective treatment for eligible patients within 24 hours of last-known-well time, reducing disability in 40-50% of patients with large vessel occlusion. Both treatments can be given together. Aspirin 300 mg within 48 hours for non-thrombolysed patients. Admit to a stroke unit — reduces mortality and disability by 20% regardless of stroke severity. Blood pressure management: cautious reduction only in haemorrhagic stroke (target systolic below 140 mmHg); avoid aggressive BP lowering in acute ischaemic stroke (maintains penumbral perfusion). Secondary prevention: anticoagulation (warfarin or DOACs — apixaban, rivaroxaban, dabigatran) for AF-related stroke; antiplatelet therapy (aspirin + clopidogrel briefly for non-cardioembolic TIA/minor stroke, then single antiplatelet); statin therapy; carotid endarterectomy or stenting for symptomatic carotid stenosis above 50-70%.

Major stroke causes permanent neurological disability — hemiplegia, aphasia (affecting 30% of survivors), dysphagia (present in 50% acutely, causing aspiration pneumonia), cognitive impairment, and depression (post-stroke depression affects 30-40%). Urinary incontinence and pressure ulcers affect immobile patients. Post-stroke epilepsy develops in 5-15% of survivors. The highest recurrence risk is in the first 48-72 hours after TIA — 10% risk of stroke within 90 days, largely preventable with dual antiplatelet therapy and statins. Secondary complications of immobility include deep vein thrombosis, pulmonary embolism, and pneumonia — the leading causes of early stroke mortality. Shoulder subluxation and spasticity from hemiplegia cause chronic musculoskeletal pain and restrict rehabilitation progress.

Blood pressure control is the single most effective stroke prevention strategy — optimal target below 130/80 mmHg. Detection and anticoagulation of atrial fibrillation prevents 60-70% of AF-related strokes. Smoking cessation reduces stroke risk by 50% within 1 year. Control diabetes (HbA1c below 53 mmol/mol), manage hypercholesterolaemia with statins (high-intensity atorvastatin for those at high cardiovascular risk), maintain healthy weight, exercise regularly, limit alcohol, and treat obstructive sleep apnoea. Opportunistic AF screening with pulse palpation and ECG in primary care for patients over 65. Aspirin is NOT recommended for primary stroke prevention in people without established cardiovascular disease — the bleeding risk outweighs the benefit. After TIA or stroke, all modifiable risk factors require aggressive management.

Stroke is a medical emergency — every minute of delay increases irreversible brain damage. Call emergency services (999 in the UK, 911 in the USA) immediately if you or anyone shows any of the FAST signs: Face drooping, Arm weakness, Speech difficulty, or Time to call for help. Also call immediately for sudden severe headache unlike any before, sudden vision loss, sudden loss of balance or coordination, or sudden confusion. Do not drive the patient to hospital — call an ambulance. Do not wait to see if symptoms resolve — even brief TIA symptoms require immediate emergency evaluation due to high early stroke risk. Do not give aspirin before ambulance arrival without medical advice. Time to treatment is the most critical determinant of stroke outcome.