Cerebellar Abscess Induced by Cochlear Fistula due to Chronic Suppurative Otitis Media

Cochlear fistulas with cholesteatoma as the primary disease have been reported frequently in the relevant literature. However, there are no reports of cochlear fistula without cholesteatoma due to chronic suppurative otitis media with intracranial complications. We report a case of cochlear fistula due to chronic otitis media that was diagnosed after the onset of a cerebellar abscess. The patient was a 25-year-old man with severe autism. He was admitted to our hospital with otorrhea from his left ear, emesis, and impaired consciousness. Computed tomography (CT) of the head showed left suppurative otitis media, left cerebellar abscess, and brainstem compression due to hydrocephalus. Right extra-ventricular drainage and brain abscess drainage were urgently performed. The next day, foramen magnum decompression and abscess drainage with partial resection of the swollen cerebellum were performed for decompression purposes. He was subsequently treated with antimicrobial therapy, but magnetic resonance imaging of the head showed an increase in the size of the cerebellar abscess. Re-examination of the temporal bone CT scans revealed a bony defect in the left cochlear promontory angle. We assumed that the cochlear fistula was responsible for the otogenic brain abscess. Thus, the patient underwent surgical closure of the cochlear fistula. After the operation, the cerebellar abscess lesion gradually shrank, and his general condition stabilized. Cochlear fistula should be considered in the management of patients with inflammatory middle ear disease associated with otogenic intracranial complications in the middle ear.