Unusual presentation of infectious intracranial aneurysm with sequential hemorrhagic and ischemic components

Infectious intracranial aneurysm (IIA), a rare type of cerebral aneurysm, is often observed in patients with infective endocarditis. Hemorrhage or infarction often occurs; however, the presentation of both hemorrhagic and ischemic components is rare. A 41-year-old man with progressive motor weakness, dysarthria, and severe headache was admitted to our hospital. Brain computed tomography scan revealed a scanty subarachnoid hemorrhage (SAH), and diffusion magnetic resonance imaging confirmed acute cerebral infarction around the external capsule and insular lobe. A digital subtraction cerebral angiogram revealed an obstruction in the middle cerebral artery (MCA). The patient's neurological symptoms improved remarkably on the fifth day, and a follow-up angiogram revealed recanalized MCA with pseudoaneurysm, which was not observed on the previous angiogram. A blood culture result confirmed bacteremia, and the patient was then diagnosed with infective endocarditis. The pseudoaneurysm was treated with anastomosis of the superficial temporal artery and MCA with trapping of the parent artery. He was discharged with no neurological deficits. Herein, we present a patient with IIA, who sequentially developed SAH and cerebral infarction, and underwent extracranial-intracranial bypass with trapping of the parent artery. Although the treatment strategy for IIA is controversial, the treatment plan should be cautiously discussed with the patient. In addition, the assessment of an underlying infectious disease is required.