In obstructive jaundice, which fecal marker is decreased?

In obstructive jaundice, which fecal marker is decreased?

• A. Increased Fecal Urobilinogen
• B. Decreased Fecal Urobilinogen
• C. No Change in Fecal Urobilinogen
• D. Increased Fecal Urobilinogen and Bilirubin

Answer: (B)

In obstructive jaundice, the flow of bile into the intestine is blocked, so bilirubin cannot reach the gut to be converted by bacteria into urobilinogen. Since less bilirubin enters the intestinal tract, there is less substrate for the formation of fecal urobilinogen, leading to a decrease in this marker. Clinically, this also explains pale stools due to reduced stercobilin. In contrast, conditions that increase bilirubin delivery to the gut, like hemolysis, would raise fecal urobilinogen, not decrease it.

In obstructive jaundice, the flow of bile into the intestine is blocked, so bilirubin cannot reach the gut to be converted by bacteria into urobilinogen. Since less bilirubin enters the intestinal tract, there is less substrate for the formation of fecal urobilinogen, leading to a decrease in this marker. Clinically, this also explains pale stools due to reduced stercobilin. In contrast, conditions that increase bilirubin delivery to the gut, like hemolysis, would raise fecal urobilinogen, not decrease it.