A case with ruptured bacterial aneurysm following meningitis

Abstract

Meningitis frequently causes cerebral infraction but rarely causes aneurysm formation and rupture. Magnetic resonance imaging (MRI) and computer tomography (CT) revealed abnormal density areas of suspected cerebral infarctions in the left frontal and occipital lobes. Although her general condition was improved by medication the sudden onset of subarachnoid hemorrhage with a huge hematoma in the fronto-temporal lobe was observed on the 11th day of treatment. Cerebral angiography showed a fusiform aneurysm at the distal branch of a right middle cerebral artery. Because the extravasation from the aneurysm occurred during the procedure, the aneurysm was trapped and resected through the left pterional approach. The partial dilated frontal branch, not observed in the pre-operative angiography, originated from the aneurysm. The dilated vessel was trapped and resected. Histologically, inflammatory cells markedly infiltrated into the whole wall of the aneurysm. The aneurysm had no elastic lamina, but the elastic lamina was preserved in the dilated abnormal branch. We suggest the aneurysm formation and multiple cerebral infarctions were caused by the strong extravascular inflammation resulting from meningitis.