Subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH, pronounced /ˌsʌbəˈræknɔɪd ˈhɛm(ə)rɪdʒ/), or subarachnoid haemorrhage in British English, is bleeding into the subarachnoid space—the area between the arachnoid membrane and the pia mater surrounding the brain. This may occur spontaneously, usually from a ruptured cerebral aneurysm, or may result from head injury. Symptoms include an intense headache with a rapid onset ("thunderclap headache"), vomiting, and an altered level of consciousness. The diagnosis is generally made with a CT scan of the head, or occasionally by lumbar puncture. SAH is managed with close observation and prompt neurosurgical investigations, medications and other treatment methods to help prevent recurrence of the bleeding and complications.