Occurrence and implications of seizures in subarachnoid hemorrhage due to ruptured intracranial aneurysms.

The records of 100 consecutive cases of subarachnoid hemorrhage due to ruptured aneurysm were reviewed to determine the incidence and the prognostic implications of seizures during the acute phase. Seizures occurred in 26% of the patients. Sixty-three per cent of the seizures occurred near the onset of the initial hemorrhage. The occurrence of these early seizures did not correlate with the location of the aneurysm or the prognosis. Most of the remaining seizures occurred immediately after rebleeding, with no greater morbidity or mortality compared to all patients who rebled. Pathogenic mechanisms of seizures associated with subarachnoid hemorrhage are proposed and discussed.