AP-VAS 2012 case report: a case of myeloperoxidase antineutrophil cytoplasmic antibody-positive microscopic polyangiitis with rapidly progressive glomerulonephritis and hearing loss.

A 74-year-old Japanese woman was admitted to our hospital because of fever, fatigue, and hearing loss associated with vertigo. She had a 1-year history of hearing impairment that got worse gradually and had been treated as otitis media with effusion, but without remarkable improvement. After admission, she developed renal dysfunction associated with hematuria and proteinuria. Laboratory tests showed leukocytosis and elevated C-reactive protein. Myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) was elevated, but proteinase-3 antineutrophil cytoplasmic antibody (PR3-ANCA) was negative. Renal biopsy revealed pauci-immune focal necrotizing glomerulonephritis with crescents. She was diagnosed as having MPO-ANCA-associated polyangiitis. After treatment with 500 mg methylprednisolone applied intravenously for 3 days, followed by 40 mg prednisolone administered orally, renal function recovered completely. Her hearing also improved. Although otolaryngological symptoms are common in PR3-ANCA associated vasculitis, hearing loss is a rare manifestation of MPO-ANCA associated vasculitis (MPO-AAV). Our case suggests that AAV should be considered in the differential diagnosis of hearing loss.