Autoimmune Chronic Pancreatitis Relapsing Despite the Maintenance Dose of Steroid
A 59 year old man was admitted to another hospital because of epigastric pain and jaundice. The patient had been healthy until three months earlier when he began to experience postprandial epigastric pain and he lost 9 kg of weight. Abdominal US revealed diffuse swelling of the pancreas that was especially more prominent in the head portion. The patient was transferred to Asan Medical Center under the impression of pancreatic cancer.\nThe patient drank only a little alcohol and had no history of diabetes mellitus, hypertension, pancreatitis and biliary stone disease. On physical examination, there was a mild tenderness over the epigastric area. The other physical examination findings were unremarkable. The total bilirubin was elevated to 7.9 mg/dL (normal range: 0.2~1.2 mg/dL). Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were elevated to 214 IU/L (normal range: < 40 IU/L) and 68 IU/L (normal range: < 40 IU/L), respectively. γ-Glutamyl transpeptidase (γ-GTP) and alkaline phosphatase (ALP) were also elevated to 385 IU/L (normal range: 11~63 IU/L) and 213 IU/L (normal range: 40~120 IU/L), respectively. Serum amylase was 46 U/L (normal range: 30~110 U/L), and serum lipase was 22 U/L (normal range: 22~51U/L). The CA19-9 was 24.5 U/mL (normal range: < 37 U/mL).\nThe total IgG concentration was normal (1,230 mg/dL, normal range: 694~1,618 mg/dL), but the serum IgG4 had not been initially measured. The test for lupus anticoagulant was positive, while the other autoantibodies such as anti-nuclear antibody, anti-mitochondrial antibody, rheumatoid factor and anti-smooth muscle antibody were all negative. Anti-carbonic anhydrase II antibody and anti-lactoferrin antibody were not measured.\nA dynamic CT scan revealed diffuse enlargement of the whole pancreas. An ERCP showed diffuse, irregular narrowing of the main pancreatic duct () and narrowing of the intrapancreatic common bile duct. An US-guided core needle biopsy was preformed, and we targeted the enlargedportion of the pancreatic head for differentiating between benign and malignant disease of the pancreas. Pancreatic histology confirmed marked lymphoplasma cell infiltration and fibrosis with acinar atrophy.\nThe patient was diagnosed as having autoimmune chronic pancreatitis based on the diagnostic criteria (characteristic pancreatic imaging, histologic findings and positive autoantibody) for autoimmune pancreatitis proposed by the Japan Pancreas Society. He was treated with prednisolone (40 mg/day) and by inserting a plastic stent (10 Fr, 5 cm) for the narrowing of the common bile duct. Three months after treatment with prednisolone (40 mg/day), a follow-up ERCP showed dramatic improvement of the narrowing () of both the main pancreatic duct and the common bile duct. The swollen pancreas returned to normal size on dynamic CT scan. The abnormal laboratory findings were normalized and he gained about 4 kg of weight. As a result, the biliary stent was removed and the daily dose of prednisolone was then gradually tapered to 5 mg over a period of 6 months. Since then, the patient had taken low dose steroid (5 mg/day) without discontinuation.\nNine months after maintenance therapy with 5mg prednisolone/day (sixteen months after the start of steroid treatment), the patient again complained of epigastric pain and jaundice of two days' duration. The total bilirubin was elevated to 7.4 mg/dL. AST, ALT and γ-GTP were elevated to 366 IU/L, 268 IU/L and 170 IU/L, respectively. Serum ALP and amylase were within normal range, while serum lipase was mildly elevated to 64 U/L. Characteristically, the serum IgG4 concentration was markedly increased (840 mg/dL, normal range: 6~121 mg/dL) with a normal concentration of total IgG. The test for the initially positive lupus anticoagulant was negative. A dynamic CT scan again revealed diffuse swelling of the pancreas. The ERCP showed segmental irregular narrowing of the main pancreatic duct in the tail portion () and the narrowing of the intrapancreatic common bile duct.\nIn spite of the maintenance therapy of low dose prednisolone (5 mg/day), the patient's relapse into autoimmune pancreatitis was strongly suspected. High dose prednisolone (40 mg/day) was administered again and the biliary stent was re-inserted into the common bile duct. Three months after therapy with a daily dose of 40 mg prednisolone, the abnormal liver function tests were normalized and serum IgG4 concentration also returned to normal. Yet it is interesting that the test for anti-nuclear antibody, which was negative on the first attack and on relapse, turned positive with a titer of 1:80 and with a nucleolar pattern during the retreatment for relpase. A follow-up ERCP demonstrated obvious improvement for the narrowing of both the main pancreatic duct () and the common bile duct. His symptoms including the epigastric pain also disappeared. Six months after maintenance therapy with 10 mg prednisolone/day and tapering by 5 mg per month, he is in good health.