19th July 2023

Background

SAH is a type of intracranial haemorrhage where bleeding occurs in the subarachnoid space. It can be classed as a type of stroke, which accounts for ~5% strokes. Most commonly, a spontaneous SAH is caused by a ruptured aneurysm. Other causes include arteriovenous malformations and arterial dissection.

Risk factors include family history of SAH, smoking, hypertension and excess alcohol intake.

Classically SAH presents as a sudden onset ‘thunderclap’ headache which reaches peak intensity within minutes. Other features can include nausea, vomiting, meningism and loss of consciousness.