Zollinger-Ellison syndrome screening
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Mohamad Alkateb, MBBCh [2]
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Differentiating Zollinger-Ellison syndrome from other Diseases |
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Overview
There is insufficient evidence to recommend routine screening for Zollinger-Ellison syndrome.
Screening
- The single best screening test for Zollinger-Ellison syndrome (ZES) is by measuring fasting serum gastrin levels.
- At the time of the test, it is advised not to take gastric antisecretory medications.
- Serial multiple measurements on different days have to be performed because, fasting gastrin levels can fluctuate from day to day and can appear to be normal.
- Normal levels of serum gastrin in untreated ZES are extremely rare (<1%)
- Multiple endocrine neoplasia-type 1 (MEN 1) syndrome should be suspected if serum calcium levels are elevated.
- Gastric acid secretory test: Basal acid output (BAO) greater than 15 mEq/h or greater than 5 mEq/h in patients with a prior vagotomy and partial gastrectomy is suggestive of ZES.
- Basal gastric secretory volume greater than 140 mL in patients with no prior gastric acid–reducing surgery has a high sensitivity and specificity.
- Gastric pH less than 2.0 in the presence of a large gastric volume (>140 mL over 1 h in patients without prior gastric acid–reducing surgery) is highly suggestive of ZES.
- Provocative tests:
- Secretin stimulation test,
- Calcium stimulation test,
- Secretin-plus-calcium stimulation tests
- Bombesin test,
- Protein meal test
- Secretin stimulation test is the provocative test of choice because of its higher sensitivity. In this test, a 2-U/kg bolus of secretin is administered intravenously after an overnight fast, and serum levels of gastrin are determined at 0, 2, 5, 10, and 15 minutes. An increase in serum gastrin of greater than 200 pg/mL is diagnostic.
- Evaluation of a patient with suspected gastrinoma:
- Step 1: Fasting gastrin level are evaluated. A minimum of 3 fasting levels of gastrin on different days are measured.
- Step 2: Gastric acid secretory studies which reveal highly suggestive findings of gastrinoma:
- Basal acid output (BAO) value of greater than 15 mEq/h (OR)
- Gastric volume of greater than 140 mL and pH of less than 2.0 .
- Step 3: Perform a provocative test. The secretin stimulation test is the preferred test.
- Step 4: Perform somatostatin receptor scintigraphy (SRS).
- Step 5: Perform imaging studies to stage and localize the gastrinoma.
- Step 6: Determine if patient is a surgical candidate for tumor resection.