[Myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) -associated glomerulonephritis with acute pancreatitis: a case report].

We report here a case of a 64-year-old woman with myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) -associated glomerulonephritis who developed acute pancreatitis. The patient was admitted to our hospital because of abnormal urinalysis findings, edema, and progressive renal failure. Laboratory studies showed a high white blood cell count (11,570/μL), anemia (hemoglobin 7.8 g/dL), and elevated serum creatinine (2.36 mg/dL) and C-reactive protein (12.20 mg/dL) levels. Furthermore, the MPO-ANCA titer was very high (1,625 U/mL, normal range < 10 U/mL). Histopathological findings of the renal biopsy were consistent with microscopic polyangiitis. Accordingly, we diagnosed MPO-ANCA-associated glomerulonephritis. On the day after the renal biopsy, the patient complained of low back pain. Computed tomography (CT) revealed postbiopsy hemorrhage. Thereafter, the patient's symptoms and laboratory studies gradually worsened. A repeat CT performed a few days later revealed no changes in the perirenal hematoma; however, an enlarged pancreas head was incidentally observed. There was no obvious cause of acute pancreatitis, and MPO-ANCA-associated vasculitis, although rare, was suspected as the cause. We initiated prednisolone pulse therapy for vasculitis along with the administration of nafamostat mesilate and ulinastatin for acute pancreatitis. Subsequently, the levels of pancreatic enzymes gradually increased, but several days later, abdominal magnetic resonance imaging showed improvement in the pancreas head. The pancreatitis gradually resolved over time. Acute pancreatitis occurring concurrently with MPO-ANCA-associated glomerulonephritis is extremely rare. To our knowledge, only a few such cases have been reported and have suggested that steroid therapy may play a role in triggering pancreatic involvement. In our case, however, an enlarged pancreas head was observed before steroid therapy was initiated. Therefore, we consider our case to be very rare.