Taking Care of Pancreatitis, Not So Simple: IgG4-related Multiorgan Disease Presenting as Pancreatitis

Abstract

Introduction: Autoimmune pancreatitis (AIP) is a pancreatic manifestation of IgG4-related sclerosing disease. In type 1 AIP, extrapancreatic organs may be involved synchronously or metachronously. One hallmark of type 1 AIP is elevated serum IgG4 level. We report a patient presenting with pancreatitis found to have multiorgan involvement with IgG4-related disease in the setting of normal serum IgG4. Case: A 59-year-old male was seen in the gastroenterology clinic for complaint of abdominal pain for 4-5 months, worse with meals, associated with nausea, night sweats, and 20-pound weight loss in 3 months. He denied vomiting, diarrhea, hematemesis, melena, hematochezia. He quit smoking 3 years ago, alcohol 10 years ago. Past history: skin vasculitis treated with oral steroids 3 years ago. Two CT scan abdomen/pelvis in the last 4 months were unremarkable. Physical exam: tenderness in epigastrium, right upper quadrant. Laboratory value: lipase 1,322, amylase 384, BUN/creat 25/1.7, HB 12.2, alk phos 298, ESR >140, C-reactive protein 87.3, serum triglyceride 151. The patient was not on medication known to cause pancreatitis. He was treated with IV fluids, bowel rest, pain medication. MRI abdomen: diffuse pancreatic body enlargement, bilateral renal enlargement and enhancement. Further work up revealed ANA titer 1:80, positive rheumatoid factor, rest of autoimmune panel was negative. Total IgG 3359, IgM 79, IgA 183, IgE 40. IgG subclass levels were: IgG1 1,420, IgG2 953, IgG3 182, IgG4 40. At this point, considering multiorgan involvement with elevated total IgG, a kidney biopsy was obtained to confirm IgG4-related disease. Biopsy revealed lymphoplasmacytic infiltrate involving tubules with plasma cell staining for IgG4. Patient was started on oral prednisone with symptomatic improvement. Discussion: The prevalence of type 1 AIP is 2-11% in patients with chronic pancreatitis. International consensus diagnostic criteria for AIP involves five features: imaging of pancreatic parenchyma and duct, serology, other organ involvement, histology of pancreas, response to steroid therapy. The number of IgG4+ plasma cells is more sensitive and specific than serum IgG4. Not all patients with type I AIP exhibit elevated serum IgG4 levels as demonstrated in our patient.Figure: MRI: abnormal foci of ill-defined signal and enhancement in both kidneys, and pancreas.