Gastrointestinal Disorders Practice Questions
20 free Gastrointestinal Disorders practice questions for the USMLE Step 1. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
A man with chronic alcohol use presents with jaundice, ascites, and caput medusae. Which pathology underlies his condition?
- A Fibrosis and nodular regeneration
- B Portal vein thrombosis
- C Hepatic vein obstruction
- D Fatty infiltration without inflammation
Correct answer: Fibrosis and nodular regeneration
Jaundice, ascites, and caput medusae after years of heavy drinking point to alcoholic cirrhosis, whose defining pathology is diffuse fibrosis with nodular regeneration. That distorted architecture obstructs sinusoidal flow, producing the portal hypertension behind the ascites and the dilated periumbilical veins. Portal vein thrombosis and hepatic vein obstruction (Budd-Chiari) also raise portal pressure but are not the consequence of chronic alcohol use, and fatty infiltration without inflammation is reversible steatosis that does not by itself cause portal hypertension.
A 25-year-old woman presents with chronic watery diarrhea, RLQ pain, and noncaseating granulomas on biopsy. Which diagnosis is most likely?
- A Ulcerative colitis
- B Crohn disease
- C Irritable bowel syndrome
- D Microscopic colitis
Correct answer: Crohn disease
Crohn disease presents with transmural inflammation, granulomas, and RLQ pain, often affecting the terminal ileum.
A patient with ulcerative colitis develops toxic megacolon. Which segment of the GI tract is always involved in UC?
- A Rectum
- B Jejunum
- C Esophagus
- D Ileum only
Correct answer: Rectum
Ulcerative colitis always begins in the rectum and may extend proximally in a continuous pattern.
A patient presents with pruritus, jaundice, and elevated alkaline phosphatase. AMA antibodies are positive. Which condition is most likely?
- A Primary biliary cholangitis
- B Primary sclerosing cholangitis
- C Autoimmune hepatitis
- D Alcoholic hepatitis
Correct answer: Primary biliary cholangitis
Primary biliary cholangitis features autoimmune destruction of intrahepatic bile ducts and positive antimitochondrial antibodies.
A man with ulcerative colitis has elevated p-ANCA. Which extraintestinal manifestation is most associated?
- A Kidney stones
- B Perianal fistulas
- C Primary sclerosing cholangitis
- D Oral aphthous ulcers
Correct answer: Primary sclerosing cholangitis
Primary sclerosing cholangitis is strongly associated with UC and often presents with p-ANCA positivity.
A patient with chronic hepatitis B develops hepatocellular carcinoma. Which marker is most specific for HCC?
- A Anti-HBc IgM
- B Alpha-fetoprotein
- C AST:ALT ratio >2
- D Prothrombin time
Correct answer: Alpha-fetoprotein
Alpha-fetoprotein is elevated in hepatocellular carcinoma and is useful for monitoring disease progression.
A 30-year-old man presents with RUQ pain and jaundice. Ceruloplasmin levels are low. Which condition is most likely?
- A Hemochromatosis
- B Wilson disease
- C Alpha-1 antitrypsin deficiency
- D Autoimmune hepatitis
Correct answer: Wilson disease
Wilson disease involves copper accumulation in liver, brain, and eyes and presents with low ceruloplasmin.
A man with cirrhosis develops confusion and asterixis. Which treatment is most appropriate?
- A Beta-blockers
- B Lactulose
- C Iron chelation
- D Proton pump inhibitors
Correct answer: Lactulose
Lactulose decreases ammonia absorption and treats hepatic encephalopathy.
A patient with Crohn disease has an increased risk for which kidney complication?
- A Calcium oxalate stones
- B Struvite stones
- C Uric acid stones
- D Cystine stones
Correct answer: Calcium oxalate stones
Fat malabsorption in Crohn disease increases oxalate absorption, predisposing to calcium oxalate stones.
A biopsy from a patient with ulcerative colitis shows crypt abscesses. What is the pattern of inflammation?
- A Transmural with skip lesions
- B Patchy discontinuous pattern
- C Continuous mucosal inflammation
- D Deep granulomatous inflammation
Correct answer: Continuous mucosal inflammation
Ulcerative colitis shows continuous inflammation limited to the mucosa, with crypt abscesses as a hallmark.
A patient with cirrhosis develops ascites. Which mechanism explains this?
- A Increased plasma oncotic pressure
- B Decreased aldosterone secretion
- C Portal hypertension with low albumin
- D Renal failure as the sole cause
Correct answer: Portal hypertension with low albumin
Ascites results from increased hydrostatic pressure (portal hypertension) and decreased oncotic pressure from low albumin.
A patient presents with fever, jaundice, and RUQ pain. What is the most likely diagnosis?
- A Gallstone pancreatitis
- B Cholangitis
- C Cholecystitis
- D Portal vein thrombosis
Correct answer: Cholangitis
Charcot’s triad (fever, jaundice, RUQ pain) is classic for acute cholangitis.
A 40-year-old woman presents with tan skin, diabetes, and liver cirrhosis. Which lab abnormality is expected?
- A Low ferritin
- B High transferrin saturation
- C Low iron levels
- D Low AST and ALT
Correct answer: High transferrin saturation
Hemochromatosis causes iron overload with elevated ferritin and transferrin saturation and can present with ‘bronze diabetes.’
A man with long-standing Crohn disease develops vitamin B12 deficiency. Which part of the GI tract is likely affected?
- A Duodenum
- B Jejunum
- C Ileum
- D Stomach
Correct answer: Ileum
The terminal ileum is responsible for B12 absorption and is commonly involved in Crohn disease.
A patient with portal hypertension develops hematemesis. Which veins are responsible for the varices?
- A Splenic and renal veins
- B Left gastric and esophageal veins
- C Iliac and femoral veins
- D Superior mesenteric and hepatic veins
Correct answer: Left gastric and esophageal veins
Esophageal varices occur due to anastomoses between the left gastric (portal) and esophageal (systemic) veins.
A patient taking NSAIDs develops melena. Which lesion type is most likely?
- A Curling ulcer
- B Cushing ulcer
- C Peptic ulcer
- D Stress ulcer
Correct answer: Peptic ulcer
NSAIDs reduce prostaglandin synthesis, compromising mucosal protection and causing peptic ulcers.
A young man presents with watery diarrhea and villous atrophy on biopsy. Symptoms improve with gluten avoidance. Which antibody is most specific?
- A Anti-gliadin
- B Anti-TTG
- C ANA
- D p-ANCA
Correct answer: Anti-TTG
IgA anti-tissue transglutaminase is the recommended first-line serologic test for coeliac disease, combining high sensitivity with high specificity. Anti-gliadin antibodies are an older, much less specific test that has largely been abandoned. ANA and p-ANCA point to connective tissue disease and to vasculitis or inflammatory bowel disease respectively, not to gluten-sensitive enteropathy.
A patient with primary sclerosing cholangitis undergoes ERCP showing a 'beaded' appearance of bile ducts. Which condition is most strongly associated?
- A Crohn disease
- B Ulcerative colitis
- C Celiac disease
- D Pancreatitis
Correct answer: Ulcerative colitis
Primary sclerosing cholangitis is strongly associated with UC and shows beading due to alternating strictures and dilation.
A man with cirrhosis presents with gynecomastia and spider angiomas. Which mechanism explains these symptoms?
- A Decreased albumin synthesis
- B Hyperestrogenemia
- C Hypothyroidism
- D Increased aldosterone degradation
Correct answer: Hyperestrogenemia
Liver failure reduces estrogen metabolism, causing elevated estrogen levels and resulting in gynecomastia and spider angiomas.
A newborn develops jaundice within 24 hours of birth and has high unconjugated bilirubin. Which condition is most likely?
- A Biliary atresia
- B Crigler–Najjar syndrome
- C Dubin–Johnson syndrome
- D Rotor syndrome
Correct answer: Crigler–Najjar syndrome
Crigler–Najjar syndrome type I causes severe unconjugated hyperbilirubinemia due to absent UDP-glucuronyl transferase.