Dilated Bile Duct and Pneumobilia

The evaluation of a dilated bile duct is primarily focused on excluding an obstructive process, limiting the flow of bile. Biliary dilation may be incidentally identified in asymptomatic patients undergoing imaging for other indications or in conjunction with clinical or biochemical abnormalities. Evaluation of this finding requires defining the normal limit of bile duct size, developing predictive markers for clinically significant biliary dilation, and understanding the accuracy and role of the various available imaging modalities. Pneumobilia is an uncommon finding of air in the biliary system, indicating a possible communication between the biliary tree and gastrointestinal tract. Careful evaluation of the patient's history and physical exam and cross-sectional imaging will usually isolate the cause to being due to postsurgical status, sphincter of Oddi incompetence, biliary-enteric fistula, or infection. In this chapter we outline clinical approaches to patients identified with a dilated bile duct or pneumobilia.