A patient presents to you with the features of biliary obstruction. He gives history of the consumption of fish while on the trip. Which of the following is most probable etiology?
**Core Concept**
Biliary obstruction can be caused by various factors including gallstones, tumors, and parasites. In this case, the patient's history of consuming fish suggests a parasitic etiology, specifically biliary ascariasis.
**Why the Correct Answer is Right**
Biliary ascariasis occurs when a swallowed Ascaris lumbricoides larva migrates to the bile duct, causing obstruction. This is more likely in individuals who consume undercooked or raw fish, which can harbor the parasite. The larva then migrates to the bile ducts, causing symptoms of biliary obstruction such as jaundice, abdominal pain, and pruritus.
**Why Each Wrong Option is Incorrect**
**Option A:** Gallstones are a common cause of biliary obstruction but are not related to fish consumption.
**Option B:** Pancreatic cancer is a possible cause of biliary obstruction, but it is not directly related to fish consumption.
**Option C:** Bile duct stones can cause biliary obstruction, but they are not typically associated with fish consumption.
**Clinical Pearl / High-Yield Fact**
Biliary ascariasis is a rare but potentially serious cause of biliary obstruction, especially in individuals who consume undercooked or raw fish.
**Correct Answer:** C.