Subarachnoid haemorrhage is bleeding into the space around the brain, most often caused by a ruptured aneurysm or significant head trauma.
Sudden, severe headache (often described as 'the worst headache ever' or like being hit on the head), neck stiffness, vomiting, sensitivity to light, confusion, and sometimes loss of consciousness.
Imaging confirms the bleed, shows where it is, often identifies the cause (aneurysm, AVM, or trauma), and guides treatment.
CT of the head is the fastest first test (very sensitive within the first 6 hours); CT angiography or catheter angiography identifies the source of bleeding.
Treatment may include endovascular coiling or surgical clipping of an aneurysm, blood pressure control, and intensive care monitoring for complications such as rebleeding, vasospasm, and hydrocephalus.
This entry explains the condition. The next step is having a radiologist interpret your specific scan, not a general definition.
