A 28 year-old man developed the lightening onset of an explosive headache followed by nausea and vomiting.

Axial CT scan. Note the subaranchnoid blood in the interhemispheric fissure anteriorly. 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. The anterior communicating artery is a common location for aneurysms.

Revised 05/01/06.
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