Pathogenesis of the "sentinel headache" preceding berry aneurysm rupture.

Pathologic examination in a case of fatal intracerebral hemorrhage from a berry aneurysm showed that the "sentinel" or warning headache in this patient was due to the leakage of blood into the subarachnoid space through a previous small tear in the wall of her saccular aneurysm. Oribital pain, transient, dysphasia, dizziness and, later, meningismus might have prompted the performing of a lumbar puncture to determine the presence of blood in the cerebrospinal fluid. This type of event is the likely pathogenetic mechanism for the premonitory headache that may precede a lethal rupture of a saccular aneurysm.