Home > Cases > Main Index > Case 66 | G.I. Index  

SRS-X The SRS Educational Resource

Case 66

Gas in the biliary tree

An elderly lady with abdominal pain

This elderly lady presented to the emergency department with abdominal pain.

Findings

There are linear air densities in a branching pattern overlying the liver. This is the appearance of gas within the biliary tree. The enlarged view shows this more clearly.

The main differential for this appearance is gas within the portal veins, an altogether more ominous sign. The gas then tends to be more peripheral and fragmented, whereas gas in the biliary tree frequently outlines the common bile duct and major branches. gas may sometimes also be visible in the gall bladder.

There are several causes for this appearance:

• Previous instrumentation or surgery: ERCP and sphincterotomy for bile duct stones is a common cause, and biliary bypass surgery (eg. choledochojejunostomy) produces a similar appearance.
• Passage of a stone through the common bile duct may allow reflux of air.
• Fistula: Most commonly due to inflammation secondary to stones. The stone may pass into the duodenum, or into the transverse colon. In the former, the stone often impacts in the distal small bowel causing small bowel obstruction (gallstone ileus), and the combination of obstruction and biliary gas should suggest this (whether the stone is visible or not). Tumour may also cause a fistula.
• Infection: emphysematous cholecystitis produces air in the gallbladder, and this may also outline the biliary tree. It is commoner in diabetics.

Previous ERCP or passage of a stone is probably the most common cause in the elderly. This lady had previously had an ERCP and her current pain was unrelated.

Diagnosis

Gas in the biliary tree

Main Index  |   Previous Case

G.I. Index  |   Previous Case

Main Index as Unknowns

G.I. Index as Unknowns