A 36-year-old woman complains of reflux symptoms and intermittent diarrhea. The diagnosis of gastrinoma is suspected so a fasting serum gastrin is obtained and found to be 280 pg/mL (normal <115 pg/mL). An abdominal CT is negative. What would you do now?

Correct Answer: B

Rationale: The correct answer is B: Measure serum gastrin in response to secretin infusion. This step is necessary to confirm the diagnosis of gastrinoma. Secretin stimulation test is used to differentiate between Zollinger-Ellison syndrome (gastrinoma) and other causes of hypergastrinemia. If serum gastrin levels remain elevated after secretin infusion, it supports the diagnosis of gastrinoma. Choice A: Refer her for an exploratory laparotomy - This is an invasive procedure and should not be the first step in the investigation of gastrinoma. Choice C: Treat her for H. pylori - This is not indicated in the management of suspected gastrinoma. H. pylori infection is not a likely cause of the symptoms described. Choice D: Obtain a dedicated small bowel series - This test is not typically used in the initial evaluation of gastrinoma. The secretin stimulation test is the preferred method for confirming the diagnosis.

Correct Answer: B

Rationale: The correct answer is B: Ischemic colitis affects the watershed areas of the colon, namely, the splenic flexure, right colon, and rectum. This is because these areas have relatively poor collateral blood supply, making them more susceptible to ischemia. Ischemic colitis typically presents with abdominal pain, bloody diarrhea, and tends to affect elderly patients with cardiovascular risk factors. Choice A is incorrect as most cases of ischemic colitis can be managed conservatively without the need for colonic resection. Choice C is incorrect as ischemic colitis can occur in individuals of any age group, although it is more common in the elderly. Choice D is incorrect because colonoscopic intervention is not always necessary for the diagnosis and management of ischemic colitis.

Correct Answer: C

Rationale: The correct answer is C - Metronidazole, lansoprazole, and clarithromycin for 14 days. This regimen includes a proton pump inhibitor (lansoprazole) to reduce stomach acid, clarithromycin to kill the bacteria, and metronidazole as an alternative antibiotic. This combination therapy is recommended by guidelines as it targets H. pylori effectively, reducing the risk of resistance. Choice A is incorrect as bismuth subsalicylate is not included in the recommended regimen. Choice B is incorrect because omeprazole is not the preferred proton pump inhibitor, and using clarithromycin alone can lead to resistance. Choice D is incorrect as the duration of treatment is insufficient for eradication. Overall, choice C is the most effective option based on current guidelines and best practices for treating H. pylori infection.

Correct Answer: A

Rationale: The correct answer is A: Prescribe an inexpensive NSAID alone. This option is the most appropriate because it balances the need for cost-effectiveness with the concern for peptic ulcers in an elderly patient. Starting with a simple NSAID reduces the risk of adverse effects and minimizes the financial burden on the patient. Option B adds misoprostol, which may help protect the stomach but increases the cost. Option C, prescribing celecoxib, is more expensive and carries a higher cardiovascular risk. Option D, adding sucralfate, does not have strong evidence for preventing NSAID-induced ulcers and adds unnecessary cost. Therefore, option A is the most suitable choice for this scenario.

Correct Answer: C

Rationale: Step 1: The patient has a positive H. pylori antibody blood test, indicating exposure to the bacteria. Step 2: Compliance with medical regimen suggests treatment for H. pylori infection. Step 3: Persistence of symptoms after treatment indicates possible treatment failure. Step 4: The urease breath test is ideal for detecting treatment failure as it directly measures the presence of H. pylori. Step 5: Therefore, choice C is correct as it identifies the appropriate test for confirming eradication failure. Summary: - Choice A is incorrect as reinfection risk is not the immediate concern. - Choice B is incorrect as a positive serum IgG doesn't definitively indicate eradication failure. - Choice D is incorrect as not all dyspepsia cases improve with H. pylori eradication.