Microscopic Polyangiitis Masquerading as Pancreatitis

Abstract

A 72-year-old female with a history of diverticulitis status post partial sigmoid colectomy, hypertension, hyperlipidemia, and osteoarthritis on chronic NSAIDs, presents with 2 months of progressive nausea, vomiting, early satiety, unintentional weight loss and abdominal pain. During an initial hospitalization she was noted to have a lipase of 1200 U/L and amylase of 130 U/L, but abdominal ultrasound did not demonstrate any gallstones or abnormality of the liver, pancreas, gallbladder or bile ducts. Laboratory findings included leukocytosis, elevated AST, ALT, alkaline phosphatase and GGT. The patient was taking acyclovir for herpes infection and was presumed to have druginduced pancreatitis, and she was discharged off acyclovir. However, her symptoms recurred along with cough and subjective fevers, and she continued to have elevated lipase and liver blood tests. CT abdomen and pelvis revealed no acute abnormalities except for a small lesion within the tail of the pancreas. Chest x-ray demonstrated diffuse bronchial wall thickening and mild bronchial opacities. The patient was admitted to the Gastroenterology service for work-up, and treated for presumed hospital-acquired pneumonia. EGD revealed no abnormalities and duodenal biopsies were negative for pathology. She was discharged, yet she again returned with similar symptoms and lab findings, except creatinine had elevated from 1.1 to 2.3 mg/dL and inflammatory markers were markedly elevated. Evaluation for vasculitis was positive for MPO and p-ANCA. Renal biopsy demonstrated pauci-immune necrotizing vasculitis. The patient was treated with steroids and rituximab, but developed alveolar hemorrhage requiring cyclophosphamide. Review of the literature reveals that abdominal pain (˜30-60%) and abnormal liver blood tests (˜85%) are common in patients with microscopic polyangiitis and other ANCA associated vasculitides. However, gastrointestinal signs and symptoms can be quite variable. There are scattered case reports of ANCA associated vasculitides mimicking inflammatory bowel disease, isolated bowel necrosis, cholecystitis and pancreatitis. Depending on the type of vasculitis, either pulmonary or renal involvement is almost always present. This case illustrates that the initial presentation of microscopic polyangiitis may be gastrointestinal, and that a broad differential should be considered in patients with vague complaints and multiorgan findings.