A 62-year-old man presents complaining of abdominal pain and diarrhea. He notes that the symptoms have been going on for three months now and he has lost about 20 pounds over that span. He also complains of migratory arthralgias for the past year. He denies any past medical history. He never smoked cigarettes and drinks about two beers per week. He denies use of illicit drugs. A review of records from an evaluation done by another physician reveals a normal thyroid-stimulating hormone level, negative ANA, a normal sedimentation rate, and a negative HIV test. He had a flexible sigmoidoscopy done, which failed to reveal any abnormalities. You refer him for upper endoscopy and a duodenal biopsy is done, which reveals extensive PAS-positive material in the lamina propria and villous atrophy. What is the most appropriate therapy for this patient?

Correct Answer: D

Rationale: The correct answer is D: Trimethoprim/sulfamethoxazole. This patient has symptoms consistent with Whipple's disease, a rare systemic infection caused by Tropheryma whipplei. The PAS-positive material in the duodenal biopsy is characteristic of Whipple's disease. Trimethoprim/sulfamethoxazole is the recommended treatment for this condition. It works by targeting the bacteria responsible for the infection. A gluten-free diet (choice A) is used for celiac disease, which presents with similar symptoms but would not show PAS-positive material on biopsy. A lactose-free diet (choice B) is used for lactose intolerance and does not address the underlying cause of the symptoms. Cholestyramine (choice C) is used to lower cholesterol levels and would not treat an infectious cause like Whipple's disease.

Correct Answer: A

Rationale: The correct answer is A: Bacterial infection by Helicobacter pylori. H. pylori is the most common cause of Peptic Ulcer Disease (PUD) as it infects the stomach lining, leading to inflammation and ulcer formation. Studies have shown a strong association between H. pylori infection and PUD. Other choices like high-fat diet and smoking can exacerbate PUD symptoms but are not the primary cause. Viral infections are not known to be a common cause of PUD. Therefore, A is the correct choice based on scientific evidence and research.

Correct Answer: B

Rationale: The correct answer is B. Sucralfate forms a protective barrier over ulcers by binding to the ulcer site and creating a physical barrier against acid and pepsin. This protects the ulcer from further damage and allows it to heal. The other choices are incorrect because: A: Sucralfate does not neutralize stomach acid, it works by forming a barrier. C: Sucralfate does not eradicate H. pylori, which is typically treated with antibiotics. D: Sucralfate does not inhibit acid production, it works by creating a protective barrier.

Correct Answer: D

Rationale: The correct answer is D: High intake of dairy products. PUD (Peptic Ulcer Disease) is commonly caused by factors like chronic NSAID use, H. pylori infection, and excessive alcohol consumption. High dairy intake does not directly contribute to PUD. Dairy products usually do not irritate the stomach lining or lead to ulcer formation. Thus, it is not a typical cause of PUD.

Correct Answer: B

Rationale: Step 1: Effective PUD management involves eradicating H. pylori bacteria. Step 2: Absence of H. pylori on follow-up testing indicates successful treatment. Step 3: Therefore, the expected outcome of effective PUD management is the absence of H. pylori on follow-up testing, making choice B the correct answer. Summary: Choices A, C, and D are incorrect as they do not directly relate to the key aspect of PUD management, which is eradicating H. pylori.