title: [A case of interstitial pneumonia preceding microscopic polyangiitis].
abstract: We encountered a case of interstitial pneumonia preceding microscopic polyangiitis (MPA). A 64-year-old asymptomatic woman was found to have interstitial pneumonia on a chest radiograph taken during a work-up before an operation for cataract. Six months later she presented with non-productive cough, low grade fever and renal dysfunction. Interstitial pneumonia worsened with new lesions. The test for MPO-ANCA was positive, though it had been negative six months previously. The histopathology of the lung by video-assisted lung biopsy showed the usual interstitial pneumonitis pattern and small vessel pulmonary vasculitis. Renal biopsy showed necrotizing glomerulonephritis. She was given a diagnosis of MPA and was immediately treated with methylprednisolone pulse therapy and a combination of prednisolone and cyclophosphamide. She has remained stable for two years. This positive inversion of MPO-ANCA, while interstitial pneumonia advanced, was of interest concerning the etiology of MPA. We discuss the important topic of the mechanism of the development of MPA.
authors.affiliation: Department of Internal Medicine, Izumi City Hospital.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Watanabe
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Matsushita
authors.forename: Masato
authors.initials: M
authors.lastname: Uji
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Suzumura
authors.forename: Keiko
authors.initials: K
authors.lastname: Nishida
authors.forename: Kazuto
authors.initials: K
authors.lastname: Hirata
mesh_terms: D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood; D005260:Female; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000150:complications* / Q000276:immunology; D008875:Middle Aged; D009195:Peroxidase / Q000276:immunology; D010488:Polyarteritis Nodosa / Q000209:etiology*
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D009195:Peroxidase