Diagnostic yield of endoscopic ultrasonography for dilation of common bile duct of indeterminate cause.

Introduction: with the widespread use of abdominal imaging, common bile duct (CBD) dilation is a common problem in the daily practice. However, the significance of a dilated CBD as a predictor of underlying disease has not been well elucidated and there are currently no guidelines for its approach.

Methods: this was a retrospective study of patients who underwent endoscopic ultrasonography (EUS) from 2010 to 2017 due to a dilated CBD detected by transabdominal ultrasonography TUS (CBD ≥ 7 mm) or computed tomography (CT) (CBD ≥ 10 mm), with no identified cause (n = 56). The aims were to assess the diagnostic yield of EUS and to identify predictors for a positive EUS.

Results: the majority of patients (n = 39) had normal findings on EUS. Abnormal EUS findings were found in 30% (n = 17) of the patients, which included choledocholithiasis (n = 6), ampuloma (n = 3), choledochal cyst (n = 2), benign CBD stenosis (n = 2), cyst of the head of the pancreas (n = 1), cholangiocarcinoma (n = 1), chronic pancreatitis (n = 1) and CBD compression due to adenomegaly (n = 1). Factors that positively related with findings on EUS were increased levels of gamma glutamyl transferase (331 U/l vs 104 U/l, p = 0.039), alkaline phosphatase (226 U/l vs 114 U/l, p = 0.041), total bilirubin (TB) (6.5 g/dl vs 1.2 g/dl, p = 0.035) and the presence of signs/symptoms (p = 0.042). Of the 21 patients (38%) who were asymptomatic with normal liver biochemical tests, four (19%) had findings on EUS.

Conclusions: the majority of patients with a dilation of the CDB have a normal EUS. Increased cholestasis enzymes, increased TB and the presence of signs and symptoms are predictors of a positive EUS.