Subarachnoid haemorrhage caused by a ruptured aneurysm: diagnosis and management

Context

Subarachnoid haemorrhage is a bleed into the fluid-filled subarachnoid space around the brain and spinal cord. Spontaneous subarachnoid haemorrhage accounts for 5% of all strokes and is estimated to occur in 2 to 20 people per 100,000 per year. In around 80% of people, the bleed arises from rupture of an intracranial arterial aneurysm. Aneurysmal subarachnoid haemorrhage is slightly more common in women than men, and can occur across a wide range of ages with a median age at presentation between 50 and 60.

The main symptom of subarachnoid haemorrhage is a sudden and severe 'thunderclap' headache but there may also be neck stiffness, altered consciousness or seizures. The condition is more easily diagnosed in people presenting with severe symptoms, unconsciousness or sudden onset acute headache but some people with subarachnoid haemorrhage present with less severe or non-specific symptoms and signs. A high index of suspicion and holistic clinical assessment are therefore required to avoid missed diagnoses.

Urgent investigation to confirm a diagnosis of subarachnoid haemorrhage facilitates treatment to prevent rebleeding from the ruptured aneurysm and reduces disability and death. Although outcomes for people with subarachnoid haemorrhage have slowly improved, the risk of death remains high and those who survive are often severely disabled. This guideline aims to improve the speed and accuracy of diagnosis and the effectiveness of treatment. It provides recommendations based on current evidence covering initial assessment, diagnostic investigations, treatment options, management of complications and follow-up care. It also identifies areas where evidence is lacking and recommends research to help inform future guidance.