Subarachnoid haemorrhage
Also called: SAH, Brain aneurysm rupture
This can be a medical emergency. Call emergency services for a sudden, extremely severe headache.
Bleeding into the space around the brain, most often from a ruptured aneurysm. It causes a sudden, explosive 'thunderclap' headache.
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Causes
- Ruptured berry aneurysm (about 85% of non-traumatic cases)
- Arteriovenous malformation
- Head injury
Risk factors
- Smoking
- High blood pressure
- Family history of aneurysms
- Polycystic kidney disease
- Heavy alcohol or cocaine use
Symptoms
- Sudden severe headache peaking within a minute
- Vomiting
- Neck stiffness
- Collapse or seizure
- Drowsiness
Diagnosis — tests and examinations
- CT brain (very sensitive within 6 hours)
- Lumbar puncture for xanthochromia if CT is normal
- CT angiography
Treatment
Medicines and medical treatment
- Nimodipine to prevent vasospasm
- Blood pressure management
- Intensive care
Operations and procedures
- Endovascular coiling or surgical clipping of the aneurysm
- External ventricular drain for hydrocephalus
Self-care, home remedies and lifestyle
- Stop smoking; control blood pressure
Possible complications
- Re-bleeding
- Delayed cerebral ischaemia (vasospasm)
- Hydrocephalus
- Death or disability
Prevention
- Blood pressure control, not smoking, screening in high-risk families
Outlook
About a third die, a third recover with disability and a third recover well.
When to see a doctor
Call emergency services for a sudden, extremely severe headache.
Sources and further reading
These sources cover this condition. They have not been checked against every statement on this page.
Related conditions
Educational overview, not medical advice. Treatment varies by person and location. Consult a qualified health professional for diagnosis or care. Read our content and model notes and privacy information.