A 28-year-old man presents with recurrent episodes of severe epigastric pain, heartburn, and watery diarrhea. Endoscopy reveals multiple jejunal ulcers. Fasting serum gastrin is 1200 pg/mL. Which additional finding would confirm Zollinger-Ellison syndrome?
- A Positive anti-parietal cell antibodies
- B Positive Helicobacter pylori stool antigen
- C Positive secretin stimulation test (rise in gastrin >120 pg/mL) ✓
- D Positive anti-intrinsic factor antibodies
Correct answer: C. Positive secretin stimulation test (rise in gastrin >120 pg/mL)
Explanation
The secretin stimulation test is the gold standard for diagnosing Zollinger-Ellison syndrome. In gastrinoma, intravenous secretin causes a paradoxical rise in serum gastrin of more than 120 pg/mL from baseline. Other causes of hypergastrinemia (atrophic gastritis, PPI use, H. pylori) do not show this paradoxical response. Anti-parietal cell and anti-intrinsic factor antibodies are seen in pernicious anemia.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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