Ultrasonographic evaluation in patients with autoimmune-related pancreatitis

Background

The concept of autoimmune-related pancreatitis (AIP) has recently been described. It is important to exclude pancreaticobiliary malignancy in patients with AIP who develop distal bile duct strictures. The aim of this study was to evaluate distal common bile duct strictures in AIP patients by endoscopic ultrasonography (EUS), intraductal ultrasonography (IDUS), and contrast-enhanced EUS (ceEUS).

Methods

Five patients with AIP, encountered from January 2000 through December 2001, underwent EUS, IDUS, and ceEUS, using Levovist as a contrast medium. EUS and ceEUS were used to follow changes in distal bile duct strictures in three of these five patients following a trial of steroid therapy.

Results

Of the five patients, four had cholestatic biochemical profiles, three were positive for autoantibodies, and three had elevated serum immunoglobulin G (IgG) or IgG4. A diffusely enlarged pancreas, narrowing of the main pancreatic duct (MPD), and strictured common bile duct in the pancreatic head were features common to all patients. Pretherapy EUS or IDUS imaging showed concentric wall thickening of the distal common bile duct causing bile duct stenosis. ceEUS showed diffuse strong enhancement of the thickened bile duct wall, possibly due to inflammation. After the steroid therapy, the stenotic lesions in both the MPD and distal common bile duct were rapidly attenuated, with a decline in biochemical cholestatic enzymes and serum IgG or IgG4 levels.

Conclusions

On EUS and IDUS imaging, concentric bile duct wall thickening and its strong enhancement by Levovist was characteristic in AIP patients.