A 35 year-old woman developed an explosive headache followed by nausea and vomiting.

Axial CT Scans without contrast: Note the bright areas which signify blood in the interhemispheric fissure, sylvian fissures, and basal cisterns. Also note the moderate hydrocephalus. Spontaneous subarachnoid hemorrhage is most often caused by a ruptured aneurysm.  They usually present with sudden headache, nausea, and vomiting, often associated with signs of increased intracranial pressure.  Rarely, an aneurysm may enlarge and present with focal signs from a mass effect, as is the case of a third nerve palsy and an aneurysm arising from the posterior communicating artery.

Revised 05/01/06.
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