Pancreatitis and Biliary Stone in PBM

Abstract

In patients with pancreaticobiliary maljunction (PBM), acute pancreatitis occurs more frequently in children (30%) than adults (9%). Pancreatitis in these cases is typically mild. Most cases reveal no evidence of pancreatitis on imaging or at surgery. This is referred to as fictitious pancreatitis or pseudopancreatitis. Increased biliary pressure caused by protein plug obstruction causes cholangiovenous reflux, by which regurgitated amylase in bile passes into the bloodstream. Biliopancreatic reflux can cause true pancreatitis, but rarely. Another factor seems necessary for the severity to advance. Chronic pancreatitis complicates PBM in 3% of patients but differs from alcoholic chronic pancreatitis in clinical and imaging points.

Gallstones have been reported to complicate PBM (adults, 25%, children, 9%). However, many reported gallstones in children must have included protein plugs stained with bile. Though rare, PBM can produce fatty acid calcium stones. Activated pancreatic enzymes in bile may release fatty acids from lecithin. Free fatty acids combine with calcium ions in bile and turn into stones. Gallstones in adults may be only coincident or form unrelated to pancreaticobiliary reflux but related to bile stasis and/or sphincter insufficiency as a result of aging. Brown pigment stones often occur after excision of the bile duct because of bile stasis and β-glucuronidase from enteric bacteria.