Five-Year Delayed Rupture of a Suspected Infectious Intracranial Aneurysm: A Case Report

Intracranial infectious aneurysms are uncommon cerebrovascular lesions caused by infection-related injury of the arterial wall and may rupture with devastating neurological consequences. A 57-year-old man had developed Streptococcus mitis infective endocarditis five years earlier, which was complicated by embolic infarction in the left posterior cerebral artery (PCA) territory and renal infarction, and he had subsequently undergone mitral valve replacement. He presented with sudden impaired consciousness and right hemiplegia while receiving warfarin therapy. Computed tomography (CT) demonstrated hemorrhage in the left PCA territory with intraventricular extension and acute obstructive hydrocephalus. Computed tomography angiography (CTA) showed a contrast spot sign within the hematoma; subsequent cerebral angiography demonstrated a distal left PCA aneurysm. Two sets of blood cultures were negative, and transthoracic echocardiography showed good prosthetic mitral valve motion without apparent vegetation. After anticoagulation reversal and endoscopic intraventricular hematoma evacuation with ventricular drainage, cerebral angiography revealed a 3.4 × 1.7 mm distal left PCA aneurysm. Because severe tortuosity and stenosis of the distal PCA prevented safe catheterization to the aneurysm site, parent artery occlusion was performed using detachable coils from the accessible distal PCA segment. No rebleeding or recurrent hydrocephalus occurred, and the patient was transferred to a long-term care hospital with severe disability. This case illustrates an unusual five-year interval between infective endocarditis-related embolic stroke and delayed rupture of a suspected infectious intracranial aneurysm.