This patient has history concerning for Zollinger-Ellison syndrome (ZES) in the context of multiple endocrine neoplasia I (previous parathyroid and pituitary tumors). Gastrin is characteristically increased ZES and administration of secretin would also increase gastrin levels.
ZES occurs when a patient has a gastrinoma - a pancreatic islet cell tumor that secretes large amounts of gastrin which lead to gastric acid hypersecretion and ulcers. Over half of gastrinomas are malignant and 20% are associated with MEN I. Diagnosis begins with the history and physical, which often reveal features of peptic ulcer disease, diarrhea, weight loss, and abdominal pain. When suspicious of a gastrinoma, diagnostic workup continues with a fasting serum gastrin level (> 1000 pg/mL is diagnostic). If this test is equivocal, a secretin injection test can be performed. Normally, secretin inhibits gastrin secretion; however, in patients with ZES, gastrin levels increase substantially after secretin administration.
Ramakrishnan and Salinas discuss peptic ulcer disease (PUD), which commonly occurs in the stomach and the proximal duodenum. Predominant causes in the U.S. are infection with H. pylori and the use of NSAIDs. Symptoms include epigastric discomfort, loss of appetite, and weight loss. For young patients without alarming symptoms, a test-and-treat strategy based on the results of H. pylori testing is recommended.
Krampitz and Norton discuss management of ZES. A gastrinoma is the culprit, usually associated with symptoms of peptic ulcer disease, GERD, and diarrhea. The diagnosis is made by fasting levels of serum gastrin and the secretin stimulation test. Because of the high association of ZES and MEN I, hyperparathyroidism should be excluded by obtaining a serum calcium and parathyroid hormone level.
Illustration A depicts a gastrinoma (arrow). Illustration B shows the classic MEN syndromes and their trademarks.
Answer 2-5: In ZES, the classic results from the fasting gastrin test and secretin test will be elevated gastrin levels. These options are less consistent with a diagnosis of ZES.
Ramakrishnan K, Salinas RC. Peptic ulcer disease. Am Fam Physician. 2007 Oct 1;76(7):1005-12.
PMID:17956071 (Link to Abstract)
Krampitz GW, Norton JA. Current management of the Zollinger-Ellison syndrome. Adv Surg. 2013;47:59-79.
PMID:24298844 (Link to Abstract)