A Case of Microscopic Polyangiitis Following Mycoplasma Infection in a Patient with MPO-ANCA Positive Pulmonary Fibrosis

• Published in: Allergology international Vol. 60; no. 1; pp. 93 - 96
• Main Authors: Takato, Hazuki, Yasui, Masahide, Waseda, Yuko, Sakai, Nobuhiko, Wada, Takashi, Fujimura, Masaki
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 2011
• Subjects: ANCA; Anti-Infective Agents - therapeutic use; Antibodies, Antineutrophil Cytoplasmic - immunology; Female; Glomerulonephritis - complications; Glomerulonephritis - diagnosis; Glomerulonephritis - drug therapy; Glomerulonephritis - immunology; Glomerulonephritis - pathology; Humans; Immunosuppressive Agents - therapeutic use; microscopic polyangiitis; Microscopic Polyangiitis - diagnosis; Microscopic Polyangiitis - drug therapy; Microscopic Polyangiitis - etiology; Microscopic Polyangiitis - immunology; Middle Aged; mycoplasma; Mycoplasma Infections - complications; Mycoplasma Infections - diagnosis; Mycoplasma Infections - drug therapy; Mycoplasma Infections - immunology; pulmonary fibrosis; Pulmonary Fibrosis - complications; Pulmonary Fibrosis - diagnosis; Pulmonary Fibrosis - diagnostic imaging; Pulmonary Fibrosis - drug therapy; Pulmonary Fibrosis - immunology; Radiography; Treatment Outcome; ANCA; microscopic polyangiitis; mycoplasma; pulmonary fibrosis
• ISSN: 1323-8930; 1440-1592
• DOI: 10.2332/allergolint.10-CR-0216

Microscopic polyangiitis is a vasculitic disease that may result in a pulmonary renal syndrome. Anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis is strongly associated with infection.
We describe a case of microscopic polyangiitis that developed in a patient with MPO-ANCA positive pulmonary fibrosis following infection with mycoplasma. A renal biopsy was undertaken following the detection of microscopic hematuria during follow-up but no abnormal findings were evident. The MPO-ANCA titer increased following infection with mycoplasma pneumonia and a second renal biopsy demonstrated crescentic glomerulonephritis. The degree of pulmonary fibrosis was unaffected.
The present case suggests that the mycoplasma infection triggered the elevation of MPO-ANCA titer and provoked glomerulonephritis in a patient with MPO-ANCA positive IPF. This case indicates the importance of testing for MPO-ANCA at the time of initial diagnosis, performing urinalysis and examining the urine sediment during follow-up and being alert to the potential onset of vasculitis in cases of pulmonary fibrosis.