Biliary reflux and gallstone pancreatitis

A stone may become lodged in the distal common bile duct near the ampulla. If the main pancreatic duct joins the CBD proximal to this, bile and pancreaticfluid may reflux up the pancreatic duct, causing inflammation and severe pain. Reflux up the common bile duct may also result in ascending cholangitis, particularly if the obstruction is prolonged or repetitive. Cholangitis may result in dilated bile ducts with mural irregularity on ultrasound, but endoscopic retrograde cholangiopancreatography (ERCP) is usually superior in demonstrating intrahepatic ductal changes of this nature. Bile reflux is also associated with anomalous cystic duct insertion (Fig. A), which is more readily recognized on ERCP than ultrasound.