Cases may be familial or sporadic. Familial cases are usually associated with the multiple endocrine neoplasia (MEN-I) syndrome.
Clinical features:
(1) severe peptic ulcer disease with hypersecretion of gastric acid and parietal cell hyperplasia (may be absent in up to 25% of patients)
(2) neuroendocrine cell hypersecretion of gastrin
(3) diarrhea (due to excess acid reaching the small intestine; I bet the pH of the stool would be low)
Peptic ulcer disease:
(1) do not respond to normal therapy or recur
(2) may be multiple
(3) ulceration present in unusual sites such as distal duodenum and proximal jejunum
(4) may result in bleeding and/or perforation
(5) severe esophagitis may be present
Neuroendocrine cell hypersecretion:
(1) insulin cell tumor of pancreas, which are often malignant
(2) non-beta islet cell hyperplasia in pancreas
(3) neuroendocrine cell tumors in the duodenum, jejunum, stomach, and/or biliary tree
Laboratory features:
(1) fasting serum gastrin levels usually elevated (may be > 1,000 pg per mL)
(2) positive secretin test (increase in serum gastrin after injection of secretin)
(3) basal acid output often > 15 mmol/h with very low pH (a random gastric aspirate >= 2.5 in a patient not taking antisecretory medications excludes ZE syndrome according to Maton)
(4) ratio of basal to maximal acid secretion >= 0.6
