USMLE Step 2 Quiz
Practice Malabsorption And Inflammatory Bowel Disease in USMLE Step 2 with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.
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A 28-year-old man with Crohn disease involving the terminal ileum and ascending colon has persistent symptoms despite a 3-month trial of high-dose oral mesalamine. He continues to have 5-6 non-bloody, loose stools per day, postprandial abdominal cramping, and fatigue. His C-reactive protein is elevated at 35 mg/L (normal < 5 mg/L). A recent colonoscopy confirms active moderate inflammation without strictures or abscesses.
Which of the following is the most appropriate next step in management?
This quiz focuses on Malabsorption And Inflammatory Bowel Disease, giving you a quick way to practice the rules, question types, and explanations that matter most for USMLE Step 2.
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A 28-year-old man with Crohn disease involving the terminal ileum and ascending colon has persistent symptoms despite a 3-month trial of high-dose oral mesalamine. He continues to have 5-6 non-bloody, loose stools per day, postprandial abdominal cramping, and fatigue. His C-reactive protein is elevated at 35 mg/L (normal < 5 mg/L). A recent colonoscopy confirms active moderate inflammation without strictures or abscesses.
Which of the following is the most appropriate next step in management?
Explanation: This patient has moderate-to-severe Crohn disease that is refractory to 5-aminosalicylic acid (5-ASA) therapy (mesalamine). For such patients, the next step in management is to escalate therapy. Biologic agents, such as anti-TNF therapy (e.g., infliximab, adalimumab), are highly effective for inducing and maintaining remission in moderate-to-severe Crohn disease. Increasing the mesalamine dose or switching to another 5-ASA like sulfasalazine is unlikely to be effective. Antibiotics are used for infectious complications like abscesses or for some cases of perianal disease, not for uncomplicated luminal inflammation.
A 38-year-old woman with a history of type 1 diabetes presents to a dermatology clinic with a 1-year history of an intensely pruritic rash. On examination, there are symmetric clusters of erythematous papules and vesicles over her elbows, knees, and buttocks. She denies any significant gastrointestinal symptoms such as diarrhea or abdominal pain.
A skin biopsy confirms dermatitis herpetiformis. This condition is a cutaneous manifestation of which of the following underlying gastrointestinal disorders?
Explanation: Dermatitis herpetiformis (DH) is a pathognomonic extraintestinal manifestation of celiac disease. It is caused by the deposition of IgA antibodies in the dermal papillae, which triggers an inflammatory response. The vast majority of patients with DH have histologic evidence of celiac disease on small bowel biopsy, even if they do not have overt gastrointestinal symptoms. Management involves both a strict gluten-free diet and medications like dapsone for symptomatic relief of the rash.
A 35-year-old man with a history of ulcerative colitis is hospitalized for a severe flare. He is receiving intravenous hydrocortisone. On day 4 of admission, he develops worsening diffuse abdominal pain and significant distension. His temperature is 39.1°C (102.4°F), and his white blood cell count is 22,000/mm³. An urgent abdominal X-ray reveals a transverse colon diameter of 8 cm with loss of haustrations.
This patient is at most immediate risk for which of the following complications?
Explanation: The clinical picture of severe colonic dilation (transverse colon > 6 cm) accompanied by signs of systemic toxicity (fever, leukocytosis) is diagnostic of toxic megacolon. This is a life-threatening complication of severe colitis, most commonly seen in ulcerative colitis. The inflamed, dilated, and thinned bowel wall is at high risk for perforation, which can lead to peritonitis, sepsis, and death. Therefore, perforation is the most immediate and feared complication requiring urgent surgical consultation.
A 29-year-old woman with a 5-year history of ileal Crohn disease presents with a 4-day history of fever and worsening right lower quadrant pain. On examination, she is febrile to 38.8°C (101.8°F). There is a tender, palpable fullness in the right lower quadrant of her abdomen. Her white blood cell count is 17,500/mm³.
Which of the following is the most appropriate initial step in this patient's management?
Explanation: This patient's presentation is highly suspicious for an intra-abdominal abscess, a known complication of penetrating Crohn disease. The first step in management is to confirm the diagnosis and delineate the anatomy of the abscess. A CT scan of the abdomen and pelvis with intravenous and oral contrast is the imaging modality of choice for this purpose. It will confirm the presence, size, and location of the abscess and help guide subsequent therapy, which typically involves percutaneous drainage and broad-spectrum antibiotics. Starting immunosuppressants like prednisone or infliximab is contraindicated in the setting of an undrained abscess.
A 42-year-old man was diagnosed with ulcerative colitis involving the entire colon (pancolitis) at age 34. His disease has been in remission for the past 5 years on maintenance therapy with mesalamine. He presents for a routine follow-up visit and feels well.
According to current guidelines, which of the following is the most appropriate recommendation regarding colorectal cancer screening for this patient?
Explanation: Patients with long-standing, extensive inflammatory bowel disease (involving more than the rectum) are at increased risk for colorectal cancer. Surveillance colonoscopy is recommended to begin 8-10 years after the initial diagnosis. This patient was diagnosed 8 years ago with pancolitis, so it is appropriate to begin surveillance now. The frequency of subsequent colonoscopies (typically every 1-3 years) depends on prior findings, disease activity, and other risk factors. Fecal testing is not sufficient for surveillance in IBD.
A 36-year-old man presents with a 6-month history of frequent, bloody diarrhea and tenesmus. He undergoes a colonoscopy. The gastroenterologist notes that the rectal mucosa is erythematous, friable, and granular, with a complete loss of the normal vascular pattern. This inflammation extends continuously from the anal verge to the splenic flexure, where there is an abrupt transition to normal-appearing mucosa. The terminal ileum is examined and appears normal.
These endoscopic findings are most consistent with a diagnosis of:
Explanation: The endoscopic findings described are classic for ulcerative colitis. Key features include: 1) inflammation starting in the rectum (proctitis), 2) continuous inflammation extending proximally without intervening normal mucosa ('skip lesions'), and 3) absence of small bowel involvement. Crohn disease is typically characterized by skip lesions, rectal sparing, deeper ulcers, and frequent terminal ileum involvement. Ischemic and infectious colitis can have varied appearances but do not typically present with this chronic, continuous pattern starting in the rectum.
A 34-year-old man with a long history of Crohn disease develops a perianal fistula. On examination, there is a single external opening approximately 2 cm from the anal verge, which drains a small amount of clear fluid without pus. The fistula tract feels non-indurated, and the patient reports no significant pain. He is otherwise in clinical remission with no active luminal symptoms.
Which of the following is the most appropriate initial medical therapy for his fistulizing disease?
Explanation: For simple, asymptomatic or mildly symptomatic perianal fistulas in Crohn disease, a course of antibiotics is often the first-line medical therapy. Metronidazole, with or without ciprofloxacin, can help reduce fistula drainage and inflammation. Biologic agents like infliximab are highly effective but are typically reserved for more complex, symptomatic, or refractory fistulas due to cost and potential side effects. Topical steroids and oral mesalamine are ineffective for treating fistulizing Crohn disease.
A 25-year-old man is newly diagnosed with mild ulcerative proctosigmoiditis after presenting with rectal bleeding and urgency. He has approximately 3-4 bowel movements per day with some blood. He has no fever, tachycardia, or anemia. His C-reactive protein and erythrocyte sedimentation rate are normal.
Which of the following is the most appropriate initial treatment to induce remission?
Explanation: For mild-to-moderate distal ulcerative colitis (proctitis or proctosigmoiditis), topical therapy with a 5-aminosalicylic acid (5-ASA) agent is the first-line treatment. Mesalamine enemas can reach the sigmoid colon and are more effective than oral 5-ASA agents for distal disease because they deliver a higher concentration of the active drug to the site of inflammation. Systemic corticosteroids (prednisone), immunomodulators (azathioprine), and biologics (infliximab) are reserved for more extensive or severe disease.
A 55-year-old woman with a 20-year history of celiac disease, who has been asymptomatic on a strict gluten-free diet, presents with a 3-month history of abdominal pain, diarrhea, and a 10-kg (22-lb) weight loss. A thorough dietary review finds no evidence of recent gluten exposure. Her IgA anti-tTG antibody test is negative. Upper endoscopy reveals thickened folds and ulceration in the jejunum. Biopsies are taken.
Which of the following is the most concerning potential diagnosis in this patient?
Explanation: This patient's presentation of new, severe symptoms ('alarm symptoms' like weight loss and pain) after a long period of well-controlled celiac disease is highly concerning for a malignancy. Enteropathy-associated T-cell lymphoma (EATL) is a rare but well-known complication of long-standing celiac disease. The endoscopic findings of ulceration are also suspicious. While other conditions like refractory celiac disease or SIBO are possible, the severity of the presentation makes EATL the most urgent and concerning diagnosis to exclude.
A 26-year-old woman with no significant past medical history presents with a 3-month history of crampy lower abdominal pain and bloody diarrhea. She notes that her symptoms began about one month after she quit a 10-year smoking habit. She has a family history of inflammatory bowel disease in her mother. Colonoscopy reveals continuous inflammation limited to the rectum and sigmoid colon.
The onset of this patient's condition after smoking cessation is a well-described phenomenon associated with which of the following?
Explanation: Smoking has a paradoxical and opposing effect on the two main types of IBD. It is a significant risk factor for the development and worsening of Crohn disease. Conversely, smoking appears to be protective against ulcerative colitis. It is a well-recognized clinical observation that a subset of patients develop ulcerative colitis for the first time or experience a significant flare of their disease shortly after quitting smoking. The colonoscopy findings of continuous distal inflammation are also consistent with ulcerative colitis.
A 40-year-old man with a 15-year history of Crohn disease presents with acute onset of severe left eye pain, photophobia, and blurred vision. His bowel symptoms are currently well-controlled on adalimumab. On physical examination, there is conjunctival injection, and his pupil is constricted. Slit-lamp examination by an ophthalmologist reveals inflammatory cells and flare in the anterior chamber.
Which of the following is the most likely diagnosis for his ocular symptoms?
Explanation: Anterior uveitis (or iritis) is one of the most common extraintestinal manifestations of inflammatory bowel disease. The classic presentation includes eye pain, photophobia, blurred vision, and conjunctival injection. The definitive finding on slit-lamp examination is the presence of inflammatory cells in the anterior chamber. Unlike peripheral arthritis, the activity of uveitis is often independent of the activity of the underlying bowel disease. Episcleritis is more common but presents with painless redness. Scleritis causes deep, boring pain. Glaucoma is characterized by increased intraocular pressure.
A 28-year-old woman with a new diagnosis of colonic Crohn disease presents with an acute onset of a warm, swollen, and painful right knee. She denies any trauma. She also reports having 5-6 loose, non-bloody stools per day. Arthrocentesis of the knee is performed, which reveals a leukocyte count of 25,000/mm³ (90% neutrophils), a negative Gram stain, and negative crystal analysis.
Which of the following is the most appropriate primary management strategy for her arthritis?
Explanation: This patient has an extraintestinal manifestation of IBD, specifically a type 1 (pauciarticular) peripheral arthropathy. The clinical activity of this type of arthritis directly mirrors the activity of the underlying bowel disease. Therefore, the cornerstone of management is to treat and control the intestinal inflammation of her Crohn disease. As her bowel disease improves, her arthritis is expected to resolve. NSAIDs like naproxen should be used with extreme caution or avoided in IBD as they can trigger disease flares. Intra-articular steroids can provide temporary relief but do not address the root cause.
A 30-year-old man reports 6 months of intermittent abdominal cramping, bloating, and excessive flatulence. He notes that his symptoms are most pronounced about an hour after his morning breakfast, which typically consists of cereal with milk and a latte. Symptoms are minimal on weekends when he eats eggs and toast instead. He occasionally has watery diarrhea but denies weight loss, bleeding, or nocturnal symptoms. Physical examination and baseline labs are unremarkable.
Which of the following is the most appropriate next step in diagnosis and management?
Explanation: The patient's symptoms are classic for lactose intolerance, a condition caused by lactase deficiency. The symptoms are directly related to the ingestion of dairy products and resolve with avoidance. In a patient with such a clear history, the most practical, cost-effective, and appropriate next step is an empiric trial of a lactose-free diet. This serves as both a diagnostic test and a therapeutic intervention. More invasive or expensive tests like endoscopy or serology for celiac disease would be considered if symptoms persisted despite dietary changes or if there were red flag symptoms (e.g., weight loss, bleeding).
A 32-year-old man with a 10-year history of inflammatory bowel disease presents with several months of progressive fatigue and generalized pruritus. He denies abdominal pain or changes in his bowel habits. His medications include oral mesalamine. Physical examination is notable for jaundice and excoriations on his back and arms. Laboratory studies show: total bilirubin 3.5 mg/dL, alkaline phosphatase 550 U/L, AST 110 U/L, and ALT 125 U/L. An endoscopic retrograde cholangiopancreatography (ERCP) is performed and shows multifocal strictures and beading of the intra- and extrahepatic ducts.
This patient's hepatobiliary condition is most strongly associated with which of the following underlying diagnoses?
Explanation: The patient's clinical presentation and ERCP findings are classic for primary sclerosing cholangitis (PSC). PSC is a chronic cholestatic liver disease characterized by inflammation and fibrosis of the bile ducts. There is a very strong association between PSC and inflammatory bowel disease, particularly ulcerative colitis. Approximately 70-80% of patients with PSC have underlying ulcerative colitis. While PSC can occur with Crohn disease, the association is much weaker.
A 24-year-old woman presents to her primary care physician with a 6-month history of non-bloody diarrhea, abdominal bloating, and an unintentional 5-kg (11-lb) weight loss. She reports feeling constantly fatigued. Her medical history is significant for type 1 diabetes mellitus. Laboratory studies show a hemoglobin of 9.8 g/dL and a mean corpuscular volume of 75 fL. Serologic testing is positive for IgA anti-tissue transglutaminase antibodies and IgA anti-endomysial antibodies. Her total serum IgA level is normal.
Which of the following is the most appropriate next step to confirm the diagnosis?
Explanation: This patient's presentation of chronic diarrhea, weight loss, and iron deficiency anemia, along with positive IgA anti-tissue transglutaminase antibodies, is highly suggestive of celiac disease. The gold standard for confirming the diagnosis is an upper endoscopy with multiple biopsies from the distal duodenum, which classically show villous atrophy, crypt hyperplasia, and intraepithelial lymphocytosis. It is crucial to perform the biopsy before the patient starts a gluten-free diet, as the intestinal mucosa can heal and lead to a false-negative result.
A 28-year-old woman was diagnosed with celiac disease by small bowel biopsy 6 months ago. She was placed on a strict gluten-free diet and has had complete resolution of her abdominal pain and diarrhea. She comes for a follow-up visit to assess her response to treatment.
Which of the following is the most appropriate test to monitor her dietary adherence and response to therapy?
Explanation: Serologic markers, particularly IgA anti-tissue transglutaminase (tTG) antibodies, are used to monitor response to a gluten-free diet in patients with celiac disease. With strict dietary adherence, these antibody titers should decrease significantly and eventually normalize, usually within 6-12 months. Persistently elevated titers suggest ongoing gluten exposure. A repeat biopsy is generally reserved for patients who do not respond symptomatically or serologically to the diet. Total IgA is checked at diagnosis to rule out IgA deficiency but is not used for monitoring.
A 33-year-old man with extensive Crohn disease has required two separate surgical resections of his terminal ileum, with a total of 100 cm removed. He presents for follow-up complaining of chronic diarrhea and fatigue. For the past month, he has also developed a new skin rash. On examination, he has scaly, erythematous plaques in the perioral area, on his hands and feet, and in the perineal region. He also has some patchy hair loss.
This patient's dermatologic findings are most likely due to a deficiency of which of the following micronutrients?
Explanation: The patient has short bowel syndrome secondary to multiple resections of the terminal ileum for Crohn disease, leading to malabsorption. His clinical presentation of a periorificial and acral dermatitis (acrodermatitis enteropathica-like), alopecia, and diarrhea is classic for zinc deficiency. The terminal ileum is a major site of zinc absorption. While he is also at high risk for vitamin B12 deficiency (absorbed in the terminal ileum) and iron deficiency, these do not cause this characteristic rash.
A 45-year-old woman with a known history of extensive ulcerative colitis presents to the emergency department with a 3-day history of worsening symptoms. She reports 12 bloody bowel movements per day, severe abdominal cramping, and feeling faint. Her temperature is 38.6°C (101.5°F), heart rate is 115/min, blood pressure is 100/65 mm Hg, and respiratory rate is 22/min. Laboratory results show a hemoglobin of 9.2 g/dL and a C-reactive protein of 150 mg/L.
Which of the following is the most appropriate initial therapy?
Explanation: This patient presents with a severe flare of ulcerative colitis, as evidenced by frequent bloody stools (>6/day), fever, tachycardia, and anemia (Truelove and Witts' criteria). The standard of care for a severe UC flare is hospitalization and initiation of intravenous corticosteroids (e.g., hydrocortisone or methylprednisolone). Oral therapies are inadequate for severe disease, and biologic agents like adalimumab are typically reserved for outpatients with moderate disease or inpatients who are refractory to IV steroids. Loperamide is contraindicated as it can precipitate toxic megacolon.
A 22-year-old man undergoes a colonoscopy to evaluate chronic, non-bloody diarrhea and abdominal pain. Biopsies are taken from multiple sites. The pathology report describes architectural distortion of the colonic crypts, crypt abscesses, and focal transmural inflammation. In addition, several well-formed, noncaseating granulomas are identified within the lamina propria.
These histologic findings are most characteristic of which of the following conditions?
Explanation: The presence of noncaseating granulomas on biopsy is a classic, though not universal, feature of Crohn disease. Transmural inflammation (involving all layers of the bowel wall) is also a hallmark of Crohn disease. In contrast, ulcerative colitis is characterized by inflammation limited to the mucosa and submucosa, and granulomas are rare. Celiac disease affects the small intestine with villous atrophy. Microscopic colitis shows either lymphocytic infiltration or a thickened collagen band, not granulomas.
A 60-year-old man with a history of alcohol-induced chronic pancreatitis presents with a 1-year history of chronic diarrhea, a 7-kg (15.4-lb) weight loss, and significant bloating. He describes his stools as being voluminous, greasy, foul-smelling, and difficult to flush. Serologic tests for celiac disease are negative. A 72-hour quantitative fecal fat test shows 20 grams of fat per 24 hours (normal <7 g/24h).
This patient's malabsorption is most likely caused by a deficiency of which of the following?
Explanation: The patient's history of chronic pancreatitis combined with clinical signs of fat malabsorption (steatorrhea) and a positive quantitative fecal fat test points to exocrine pancreatic insufficiency (EPI). In EPI, the pancreas fails to produce adequate amounts of digestive enzymes. The deficiency of pancreatic lipase leads to impaired digestion of dietary fats, resulting in steatorrhea and weight loss. Bile salt deficiency causes fat malabsorption but is less likely given the history. Lactase deficiency causes osmotic diarrhea, not steatorrhea. Intrinsic factor deficiency causes vitamin B12 malabsorption.