neurologic disorders
Subarachnoid Hemorrhage (SAH)
Introduction
Subarachnoid hemorrhage is sudden bleeding into the subarachnoid space. The most common cause of spontaneous bleeding is a ruptured aneurysm. Symptoms include sudden, severe headache, usually with loss or impairment of consciousness. Secondary vasospasm (causing focal brain ischemia), meningismus, seizures, and hydrocephalus (causing persistent headache and obtundation) are common. Diagnosis is by CT or MRI; if neuroimaging is normal, diagnosis is by cerebrospinal fluid analysis to look for xanthochromia and red blood cells. Treatment is with supportive measures and neurosurgery or endovascular measures, preferably in a comprehensive stroke center. 