MPO-ANCA陽性自己免疫性疾患に合併した感音難聴の4症例

抄録

In recent years, there have been many reports on the so-called autoimmune sensorineural hearing loss. But there are a number of unclarified points regarding the mechanism of this disease. We had four cases of sensorineural hearing loss related with anti-neutrophil cytoplasmic antibodies against myeloperoxidase (MPO-ANCA)-associated vasculitis.
Four patients who had been treated at the Department of Otolaryngology, Jichi Medical School with MPO-ANCA-associated sensorineural hearing loss (2 males and 2 females) were selected for this study. All patients had been complicated by autoimmune diseases (glomerulonephritis, pulmonary fibrosis, arthritis and Sjogren's syndrome) and had positive MPO-ANCA titer. They were referred to us for the sudden onset of bilateral hearing loss. Pure tone audiometry revealed bilateral moderate to severe sensorineural hearing loss. Three of them complained of vertigo and had nystagmus. Electronystagmogram (ENG) revealed unilateral canal paresis (CP) in two patients. These results indicated that MPO-ANCA-associated vasculitis could cause not only hearing loss but also vestibular disturbance. All the patients received high-dose adrenocorticosteroid. With the treatment, they had marked improvement of hearing loss and vertigo as well as systemic disease, and titer of serum MPO-ANCA decreased.
Although any organ may be affected by MPO-ANCA-associated vasculitis, there are few reports on cases of MPO-ANCA-associated progressive hearing loss and vestibular disturbance.The present cases suggest the possibility of hearing loss and vestibular disturbance resulted from small vessel vasculitis in the inner ear. It is expected that MPO-ANCA is possibly a good marker for diagnosis and follow-up of some of autoimmune sensorineural hearing loss.