[Interstitial pneumonia complicated by rapidly progressive glomerulonephritis associated with anti-myeloperoxydase...

A 78-year-old man was admitted to our hospital in October 1994 because of renal dysfunction. The level of anti-myeloperoxidase antibody in serum was 500 EU/ml, and examination of a specimen obtained by open renal biopsy revealed crescentic glomerulonephritis. A chest roentgenogram revealed no abnormality. Administration of prednisolone was started at 50 mg/day, and the dosage was then tapered. Renal function remained stable, but on interstitial shadow appeared on the chest roentgenogram. Pulmonary function tests showed a restrictive ventilatory abnormality and a low diffusing capacity. A thoracoscopic lung biopsy was done in April 1995, and microscopic examination of the specimen showed interstitial pneumonia with relatively young granulation. The dosage of prednisolone was increased to 50 mg/day, after which the interstitial shadow decreased and pulmonary function improved. The level of anti-myeloperoxydase antibody in serum was 16 EU/ml (weakly positive). Alveolar hemorrhage can occur in cases of rapidly progressive glomerulonephritis. In addition, interstitial pneumonia or pulmonary fibrosis can also complicate this condition. In the present case, glomerulonephritis associated with anti-myeloperoxydase antibody co-existed with interstitial pneumonia. This case is valuable because both renal biopsy and lung biopsy specimens were available.