A 63-year-old man with acute abdominal pain and laboratory signs of rapid progressive renal disease.

A 63-year-old previously healthy man complained of increasing dyspnoea for 2 weeks. A cardiologist saw him, and an echocardiograph showed a mild pericardial effusion. Serum creatinine concentration was 4.6mg/dl, and the patient was admitted to our clinic for further diagnostic work-up. He had no history of renal disease, a routine serum creatinine was normal 6 months previously, and he was taking no regular medication. In addition to the dyspnoea, the patient complained of abdominal pain in the right lower quadrant that began 24 h before admission. Physical examination revealed normal pulmonary and cardiac findings (BP 150/90 mmHg), but a local tenderness in the lower right abdomen. Ultrasound showed fluid-filled bowels with reduced peristalsis; the kidneys appeared swollen and increased in size. Serum creatinine was 6.3mg/dl, BUN 99mg/dl, haemoglobin 12.1 g/dl, leukocytes 22.9 10/l and C-reactive protein 210mg/l. Urinalysis showed red blood cell casts, acanthocytes, and a proteinuria >300mg/dl (dipstick; a subsequent 24 h urine collection contained 1000mg of albumin). Chest radiography was normal. A working diagnosis of an acute nephritic syndrome was made. The patient was scheduled for percutaneous renal biopsy the next day. However, during the night, he developed an abdominal emergency with signs of generalized peritonitis. Laparotomy revealed several ischaemicand necrotic-appearing segments of the distal jejunum (Figure 1A) that were removed, and end-to-end anastomosis was performed. Histopathology showed necrotizing vasculitis of submucosal small vessels (arterioles and venules), infiltration of the vessel walls with neutrophils (Figure 1B) and hyaline thrombi. Medium size and larger vessels were normal. The patient was treated with intravenous methylprednisolone pulse therapy, followed by oral prednisolon. At this time, the results of further serological tests were obtained showing negative ANA, ENA and anti-GBM antibodies, normal C3 and C4, but a p-ANCA (antineutrophil cytoplasmic antibodies) against myeloperoxidase (MPO) of 32 (positive >9), whereas c-ANCA (against proteinase 3) was negative. There was no serological evidence for hepatitis B or C, and no cryoglobulins could be detected. Renal biopsy was performed 5 days later and showed a focal necrotizing glomerulonephritis with diffuse endothelial and mesangial proliferation with crescents (Figure 1C). However, some glomeruli were already sclerosed, suggesting ongoing disease for some time. Immunohistology showed deposition of fibrin (Figure 1D) but no granular or linear immunoglobulin deposits. Oral cyclophosphamide (75mg) was added to his regimen. This reduced dose was selected because of severe reduction in renal function (serum creatinine was 7.8mg/dl at this time). Unfortunately, renal function deteriorated further. The patient is now on maintenance haemodialysis. He is currently being treated with azathioprine, and so far has had no recurrence of abdominal pain. The p-ANCA recently was <10. Correspondence and offprint requests to: Professor Dr Gunter Wolf, Department of Medicine, Division of Nephrology and Osteology, University of Hamburg, University Hospital Eppendorf, Pavilion 61, Martinistrasse 52, D-20246 Hamburg, Germany. Email: Wolf@ uke.uni-hamburg.de