A Patient With Diarrhea And Epigastric Pain Unresponsive To Treatment

One of your patients presents complaining of diarrhea and epigastric pain unresponsive to H2 blockers or PPIs. He denies smoking tobacco, taking NSAIDs, or drinking alcohol. Endoscopy reveals several ulcers. Biopsy for H. pylori is negative and there is no malignancy.
Which of the following would be the most appropriate laboratory test to obtain in order to discover an etiology for the multiple ulcers (and diarrhea)?

A) Vasoactive intestinal peptide (VIP).
B) Gastrin.
C) Glucagon.
D) Somatostatin.
E) None of the above.

Answer:



B. Gastrin

Discussion: Some sort of screening test for gastrinoma is warranted in a patient who has recurrent or refractory ulcers. Zollinger–Ellison syndrome is the name given to the state in which there is acid hypersecretion secondary to increased gastrin production, usually from a gastrin-producing tumor (gastrinoma). Up to 1% of patients with PUD have a gastrinoma. Serum gastrin levels should be obtained with the patient fasting and off PPIs, as PPIs will increase gastrin levels. If the serum gastrin
is elevated, further investigations will need to be performed.
Other reasons to consider obtaining a serum gastrin level include ulcers in unusual locations, family history of ulcers, and ulcers associated with reflux esophagitis.

“A” is incorrect. VIP actually works to suppress acid secretion. VIPomas do occur (they’re actually tumors and not related to VIP patients calling you at all hours), but VIPomas are associated with watery diarrhea and hypokalemia—not ulcers.

“C,” glucagon, will not be of much help here. Glucagon over secretion results in hyperglycemia and anemia.

“D,” somatostatin, is a hormone that inhibits the secretion of gastrin and thus would be protective against ulcers. Somatostatin-secreting tumors are very rare.