Fatal basilar vasculopathy complicating bacterial meningitis.

Abstract
Bacterial meningitis complicated by thrombosis, vasculitis, and aneurysm formation affecting both small and distal branches of cerebral vessels has been well described. Involvement of major cerebral vessels is rare and has only been documented late in the course of disease. We describe the clinical and pathological findings in a young man who presented with pontine infarction as an early manifestation of bacterial meningitis. Streptococcus milleri, an unusual organism in this setting, was cultured. Despite improvement with antibiotic therapy, the patient experienced fatal subarachnoid hemorrhage. A ruptured inflammatory aneurysm of the basilar artery, evidence of residual meningitis and vasculitis, and basilar thrombosis associated with pontine infarction were found. Bacterial meningitis, which may be associated with severe vasculopathy of the basilar artery and lead to cerebral infarction, aneurysm formation, and subarachnoid hemorrhage, should be considered in the differential diagnosis of these conditions. The role of S. milleri in meningitis and its vascular complications merits further study.