Bile and Pancreatic Secretion

A 38-year-old woman with a history of recurrent biliary colic presents with jaundice, pale stools, and dark urine. Laboratory tests show elevated direct bilirubin and alkaline phosphatase. Abdominal ultrasound confirms dilated intrahepatic bile ducts and a dilated common bile duct (8 mm) but no gallstones are visualized. Which investigation is most appropriate to identify the cause of biliary obstruction?

A 52-year-old man with chronic pancreatitis presents with steatorrhea and fat-soluble vitamin deficiencies. Regarding pancreatic secretion and its regulation, all of the following are true EXCEPT:

Regarding the composition and functions of bile, all of the following statements are correct EXCEPT:

A 52-year-old man with a 10-year history of chronic pancreatitis presents with steatorrhea, weight loss of 8 kg over 3 months, and fat-soluble vitamin deficiencies. Fecal chymotrypsin is absent. What is the most appropriate immediate next step in management?

A 38-year-old woman with acute pancreatitis (amylase 1200 U/L, lipase 2800 U/L) secondary to gallstones presents with severe epigastric pain and vomiting. Ultrasound confirms a 15 mm stone in the common bile duct with mild intrahepatic bile duct dilation. What is the most appropriate immediate next step?