Which findings support a diagnosis of choledocholithiasis?

• A. Gallstones in the gallbladder with normal CBD.
• B. CBD dilation on imaging without bilirubin elevation.
• C. CBD dilation on imaging with elevated bilirubin.
• D. No CBD dilation and normal bilirubin.

Answer: (C)

When a stone blocks the common bile duct, bile flow is obstructed, causing back-up of bile and a cholestatic pattern. The clearest sign of this in imaging and labs is dilation of the common bile duct together with elevated bilirubin. The dilation shows that something is physically obstructing the duct, and the high bilirubin confirms that bile is not draining properly, producing jaundice.

Other scenarios are less specific for a CBD stone. Gallstones confined to the gallbladder can cause biliary colic without CBD dilation or jaundice. CBD dilation with normal bilirubin might occur with partial or intermittent obstruction or very early in the course before bilirubin rises. No CBD dilation with normal bilirubin argues against an obstructing CBD stone.