Usefulness and Safety of Endoscopic Nasobiliary Drainage for Type 1 Autoimmune Pancreatitis

Objectives: Autoimmune pancreatitis (AIP) is a pancreatic manifestation of IgG4-related disease, which is complicated by extrapancreatic lesions, such as IgG4-related sclerosing cholangitis. The appropriate biliary drainage method and period for type 1 AIP remain unclear. Therefore, we aimed to clarify the usefulness and safety of endoscopic nasobiliary drainage (ENBD) for type 1 AIP in patients with jaundice. Methods: This study enrolled 83 patients with type 1 AIP who underwent steroid therapy who underwent evaluation of contrast material outflow to the jejunum using cholangiography. The ENBD was removed when the contrast material outflowed into the duodenum; an endoscopic biliary stenting (EBS) was performed if it did not outflow. Results: Cholangiography and pancreatography were achieved in 83 (100%) and 77 (93%) patients, respectively. Liver function parameters were significantly decreased after ENBD. Bile juice cytology using ENBD revealed no evidence of malignancy. Two (2%) patients developed mild pancreatitis following endoscopic retrograde cholangiopancreatography (ERCP). Endoscopic ultrasound-guided fine-needle aspiration biopsy was performed in 56 (67%) patients. ENBD was removed in 75 (90%) patients; EBS was performed in 8 (10%). Multivariate regression analysis showed pancreatic focal enlargement (OR=12.06, 95% CI: 1.28–113.62, P =0.03) as an independent risk factor for EBS. Conclusions: Although ENBD causes discomfort and the risk of self-removal, it differentiates AIP from malignant tumors, evaluates steroid effects using real-time cholangiography, and reduces the number of required ERCP procedures. ENBD could be one of the drainage options for type 1 AIP, depending on patients’ background.