当科で経験した悪性外耳道炎の 1 例

Malignant external otitis is classically described as external otitis caused by Pseudomonas aeruginosa infection in patients with diabetes mellitus. An 85-year-old man visited our ENT clinic complaining of earache and otorrhea on the right side. Pseudomonas aeruginosa was isolated from the otorrhea fluid, and the patient was referred to our hospital. The external ear was filled with granulomas, and the computed tomographic findings suggested otitis media and mastoiditis. Local antibiotic therapy was not effective, and we performed radical mastoidectomy and removed the infectious granuloma. Two months later, the patient visited our hospital again with severe headache and earache. Examination revealed evidence of facial nerve and abducens nerve paralysis. Computed tomography and magnetic resonance imaging also revealed evidence of skull base osteomyelitis, and MRSA was isolated from the otorrhea fluid. The patient was treated with intravenous antibiotics effective against MRSA for 6 weeks, which led to improvement of the headache and otorrhea. Until 6 months later, there was no relapse of these symptoms, and the facial nerve and abducens nerve palsies improved. Malignant otitis externa and skull base osteomyelitis are often serious. We report a case in which long-term antibiotic therapy was effective.