Gastrointestinal System and Nutrition

Original practice questions written to the published framework for this section. No expert has reviewed them, and they are not taken from any official exam. Try each one before you open the answer.

1. Question 1Foundational

   Which inflammatory bowel disease characteristically causes transmural inflammation with skip lesions that can occur anywhere from the mouth to the anus?

   1. AUlcerative colitis
   2. BCrohn disease
   3. CCeliac disease
   4. DMicroscopic colitis

   Show answer

   Answer: B. Crohn disease

   Crohn disease involves the full thickness of the bowel wall in discontinuous segments, which explains its fistulas, strictures, and perianal disease and its ability to affect any part of the gastrointestinal tract. Ulcerative colitis is the tempting distractor but is limited to the mucosa and submucosa and spreads continuously proximally from the rectum.

   Key insight: Skip lesions and transmural disease mean Crohn; continuous mucosal disease starting at the rectum means ulcerative colitis.

2. Question 2Foundational

   A 45-year-old woman has right upper quadrant pain after fatty meals, fever, leukocytosis, and inspiratory arrest on palpation of the right upper quadrant. Which imaging study should be obtained first?

   1. ARight upper quadrant ultrasonography
   2. BHepatobiliary iminodiacetic acid scan
   3. CCT of the abdomen with intravenous contrast
   4. DMagnetic resonance cholangiopancreatography

   Show answer

   Answer: A. Right upper quadrant ultrasonography

   Ultrasonography is the first-line study for suspected acute cholecystitis because it is fast, radiation free, and highly sensitive for gallstones, wall thickening, and pericholecystic fluid. A hepatobiliary iminodiacetic acid scan is the tempting second choice, but it is reserved for cases in which the ultrasound is equivocal and cystic duct obstruction still needs to be confirmed.

   Key insight: Suspected gallbladder disease starts with ultrasound; the nuclear scan is the tiebreaker, not the opener.

3. Question 3Intermediate

   Which hepatitis B serologic pattern indicates immunity from vaccination in a person who has never been infected?

   1. AHepatitis B surface antigen positive alone
   2. BHepatitis B surface antibody positive alone
   3. CHepatitis B core antibody positive alone
   4. DHepatitis B e antigen positive with core antibody positive

   Show answer

   Answer: B. Hepatitis B surface antibody positive alone

   The vaccine contains only surface antigen, so vaccinated people develop surface antibody without ever making core antibody. Recovery from natural infection is the tempting alternative, but it leaves both surface antibody and core antibody positive, and the presence of core antibody is what proves prior infection.

   Key insight: Core antibody separates infection from vaccination: surface antibody alone means the vaccine did its job.

4. Question 4Intermediate

   In a patient with elevated aminotransferases, an AST to ALT ratio greater than 2 to 1 most strongly suggests which cause of liver injury?

   1. AAcute viral hepatitis A
   2. BNonalcoholic fatty liver disease
   3. CAlcohol-related liver disease
   4. DAcetaminophen-induced hepatocellular necrosis

   Show answer

   Answer: C. Alcohol-related liver disease

   Alcohol-related hepatitis characteristically produces an AST to ALT ratio above 2 to 1, with both values usually staying under about 300 units per liter. Nonalcoholic fatty liver disease is the tempting distractor but typically shows the opposite pattern, with ALT higher than AST, and acetaminophen toxicity produces transaminases in the thousands.

   Key insight: AST greater than twice ALT points at alcohol; ALT greater than AST points at fatty liver or viral hepatitis.

5. Question 5Advanced

   Deficiency of which vitamin produces Wernicke encephalopathy, the triad of confusion, ophthalmoplegia, and ataxia?

   1. AThiamine
   2. BNiacin
   3. CPyridoxine
   4. DCobalamin

   Show answer

   Answer: A. Thiamine

   Thiamine, or vitamin B1, is a cofactor for pyruvate dehydrogenase and other enzymes that fuel the brain, and depleting it produces the acute encephalopathy, eye movement abnormalities, and gait ataxia of Wernicke encephalopathy. Niacin deficiency is the tempting distractor because it also causes a dementia, but pellagra adds dermatitis and diarrhea rather than ophthalmoplegia.

   Key insight: Confusion plus eye findings plus ataxia in a malnourished person means give thiamine before glucose.