ABIM Gastroenterology 2 — Questions and Answers
Question 1: A 45-year-old woman with primary biliary cholangitis has an alkaline phosphatase of 4x normal and pruritus. Which medication is first-line?
- Cholestyramine
- Ursodeoxycholic acid (UDCA) (Correct answer)
- Methotrexate
- Prednisolone
Correct answer: Ursodeoxycholic acid (UDCA)
UDCA is the first-line treatment for PBC, improving liver biochemistry, slowing histological progression, and improving transplant-free survival.
Question 2: A 30-year-old man presents with recurrent abdominal pain, weight loss, and terminal ileal involvement on imaging showing 'cobblestone' mucosa and skip lesions. What is the diagnosis?
- Ulcerative colitis
- Crohn disease (Correct answer)
- Ischemic colitis
- Infectious colitis
Correct answer: Crohn disease
Crohn disease characteristically involves any part of the GI tract with transmural inflammation, skip lesions, and cobblestoning, most commonly affecting the terminal ileum.
Question 3: A 68-year-old man with jaundice, weight loss, and painless jaundice has a CT showing a mass in the head of the pancreas with dilated biliary and pancreatic ducts (double duct sign). What is the next step?
- ERCP with brushings and biliary stent placement
- EUS-guided FNA for tissue diagnosis (Correct answer)
- Immediate Whipple procedure
- CA 19-9 level only
Correct answer: EUS-guided FNA for tissue diagnosis
EUS-guided FNA provides tissue diagnosis for pancreatic masses with high sensitivity and specificity while simultaneously staging local extension before definitive surgery.
Question 4: A patient with alcohol-related cirrhosis has hepatic encephalopathy. Ammonia is elevated. Which treatment reduces recurrence of hepatic encephalopathy?
- Long-term oral antibiotics with metronidazole
- Rifaximin plus lactulose (Correct answer)
- Branched-chain amino acid supplementation only
- Zinc supplementation only
Correct answer: Rifaximin plus lactulose
Rifaximin (a non-absorbable antibiotic) combined with lactulose is more effective than lactulose alone in preventing recurrence of overt hepatic encephalopathy.
Question 5: A 55-year-old woman presents with epigastric pain, early satiety, and unintentional weight loss for 4 months. Upper endoscopy shows a gastric ulcer. What is the most critical next step?
- Start PPI and recheck in 8 weeks
- Biopsy the ulcer edges to exclude malignancy (Correct answer)
- Test for H. pylori only
- Immediate gastrectomy
Correct answer: Biopsy the ulcer edges to exclude malignancy
All gastric ulcers require biopsy to exclude gastric cancer, as malignant ulcers can appear benign endoscopically.
Question 6: A 70-year-old man with chronic constipation presents with acute onset left-sided colonic pain and CT showing a 12 cm sigmoid loop with a 'whirl sign'. What is the diagnosis?
- Sigmoid diverticulitis
- Sigmoid volvulus (Correct answer)
- Ogilvie syndrome
- Ischemic colitis
Correct answer: Sigmoid volvulus
Sigmoid volvulus presents with a massively dilated sigmoid colon and characteristic whirl sign or 'coffee bean' sign on imaging; urgent endoscopic decompression is the initial treatment.
ABIM Gastroenterology 2
A 45-year-old woman with primary biliary cholangitis has an alkaline phosphatase of 4x normal and pruritus.
Which medication is first-line?