Pathophysiology: Aneurysms are acquired lesions related to hemodynamic stress on the arterial walls at bifurcation points and bends. Saccular or berry aneurysms are specific to the intracranial arteries because their walls lack an external elastic lamina and contain a very thin adventitia—factors that may predispose to the formation of aneurysms.
An additional feature is that they lie unsupported in the subarachnoid space.Crude SAH incidences increased from 5.5 per 100,000 person-years in 2002 to 7.5 in 2010. Standardized SAH incidences increased from 4.1 per 100,000 person-years in 2002 to 5.6 in 2010. Crude 1-year mortality rates decreased from 43% in 2002 to 19% in 2010, and the standardized 1-year mortality rate decreased from 38% in 2002 to 19% in 2010.
Surgery may be done to: • Remove large collections of blood or relieve pressure on the brain if the hemorrhage is due to an injury • Repair the aneurysm if the hemorrhage is due to an aneurysm rupture If the person is critically ill, surgery may have to wait until the person is more stable.Ongoing Research is being done at Subarachnoid haemorrhage centres.