Embolic stroke and mycotic aneurysms are the most common neurological complications of infective endocarditis. Mycotic aneurysms commonly involve intracranial arteries and are located distally over the cerebral cortex. We report a case of a 21 year old man admitted to our hospital because of fever of one week’s duration, signs of meningitis, and heart murmur. Cerebrospinal fluid and blood cultures were both negative. An echocardiogram showed a vegetation in the mitral valve 19 mm in length. Empiric antibiotic treatment was started with good response. Routine cerebral magnetic resonance angiography showed a total occlusion of the left internal carotid artery caused by heterogeneous material (probable embolism) and an image at the origin of the artery compatible with a mycotic aneurysm of 11 × 25 mm in diameter (panels A and B). Left hemisphere circulation was preserved through the circle of Willis.

The patient successfully underwent surgery for mitral valve replacement and no focal neurological deficit appeared. At hospital discharge, and after antibiotic treatment for 45 days, the patient was asymptomatic. Doppler echocardiography performed before the patient was discharged showed that the left internal carotid artery was still occluded and the mycotic aneurysm had not changed in size.

(A) Magnetic resonance angiography of supra-aortic vessels (frontal view). An occlusion of the left internal carotid artery at its origin is visible, preceded by a mycotic aneurism (white arrow). (B) Left lateral view.