A dangerous dilemma: management of infectious intracranial aneurysms complicating endocarditis.

A 41-year-old right-handed man with bicuspid aortic valve and a 3-month history of chronic fever and weight loss presented with sudden onset of severe headache. Computerised tomography of the head revealed a right basal ganglia haemorrhage. Further investigation documented Streptococcus mitis bacteraemia, a fusiform right middle cerebral artery aneurysm, and an abscess at the base of the anterior leaflet of the mitral valve. The patient subsequently died when repeat aneurysmal haemorrhage resulted in cerebral herniation and brain death while on antibiotic therapy. Infectious intracranial aneurysms (IIAs) are uncommon but severe complications of bacterial endocarditis. Several case series have been published evaluating the management of IIAs, but no randomised controlled trials exist to guide treatment decisions. Improved diagnostic techniques, microvascular neurosurgical approaches, and endovascular therapies hold the promise of improved outcomes in the future. This difficult case is used to show an approach towards the management of IIAs complicating bacterial endocarditis based on a review of the published work.