In cholecystitis, obstruction most commonly occurs at which duct?

• A. Common bile duct
• B. Hepatic duct
• C. Cystic duct
• D. Pancreatic duct

Answer: (C)

Cholecystitis usually starts when a gallstone blocks the cystic duct, the channel that drains bile from the gallbladder into the common bile duct. When this duct is obstructed, bile cannot leave the gallbladder, causing distention, reduced blood flow, and an inflammatory response in the gallbladder wall. This combination drives the inflammation characteristic of acute cholecystitis. If the blockage were in the common bile duct, bile would back up into the liver and cause jaundice and other systemic signs; obstruction of the pancreatic duct would more likely trigger pancreatitis. Therefore, the cystic duct is the most common site of obstruction in cholecystitis.