Subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) presents as a sudden severe headache, often described as "the worst headache of life," with nausea, vomiting, and photophobia.

This topic focuses on the diagnosis and management of subarachnoid hemorrhage caused by aneurysm (i.e., aneurysmal SAH).

Examination can be normal or may reveal altered consciousness, meningismus, intraocular hemorrhages, or focal findings.

Computed tomography (CT) is indicated if subarachnoid hemorrhage is clinically suspected. Lumbar puncture is indicated if CT is unrevealing. Cerebral angiography confirms the presence of aneurysms.

Initial stabilization followed by surgical clipping or endovascular coil embolization is standard therapy. Enteral nimodipine should be started early to prevent vasospasm and delayed cerebral ischemia, and improve functional outcomes.

Complications are common and include rebleeding, acute hydrocephalus, and delayed cerebral ischemia.

SAH is bleeding into the subarachnoid space and is an emergency. The most common cause of nontraumatic SAH is rupture of an intracranial aneurysm, which is the focus of this topic.[1]Suarez JI, Tarr RW, Selman WR. Aneurysmal subarachnoid hemorrhage. N Engl J Med. 2006 Jan 26;354(4):387-96. Aneurysmal SAH causes substantial morbidity and mortality. When a cerebral aneurysm ruptures, blood flows into the subarachnoid space, sometimes seeping into brain parenchyma and/or ventricles. The sudden increase in intracranial pressure, as well as the destructive and toxic effects of blood on brain parenchyma and cerebral vessels, accounts for most complications.