What is a classic stool finding in complete obstruction of the common bile duct?

What is a classic stool finding in complete obstruction of the common bile duct?

• A. Pale-colored stool
• B. Dark brown stool
• C. Normal stool color
• D. Green stool

Answer: (A)

Stool color mainly reflects bilirubin excretion into the gut and the formation of the pigment stercobilin, which gives stool its brown color. In complete obstruction of the common bile duct, bile cannot reach the intestine, so bilirubin can’t be converted to stercobilin. The result is a pale, acholic stool—the classic finding when bile flow to the gut is blocked. Normal brown stool would imply bile pigments are reaching the intestines, while green or dark brown stool suggests bile pigments are present and/or other factors are influencing color; neither fits the scenario of a complete bile duct obstruction.