Subarachnoid hemorrhage (SAH) is a clinical syndrome caused by the rupture of a diseased blood vessel at the base or surface of the brain and the direct flow of blood into the subarachnoid space.
Non-traumatic subarachnoid haemorrhage is a common and highly lethal condition, with the main cause being aneurysms, which account for approximately 85% of all cases, and other causes including non-aneurysmal haemorrhage around the midbrain, vascular malformations, dural arteriovenous fistulas, coagulation disorders, cocaine use and pituitary strokes.
In recent years, there have been significant advances in vascular interventional techniques, diagnostic methods and perioperative management. However, the prognosis for patients with subarachnoid haemorrhage remains poor, with a 45% morbidity and mortality rate and a high rate of disability in those who survive.