Zollinger-Ellison syndrome: pathogenesis, diagnosis, and management.

Zollinger-Ellison syndrome (ZES) involves hypergastrinemia produced by gastrin-secreting tumor(s) of the pancreas or duodenum. Estimated to occur in 0.1-3 per million of the United States' population, the actual prevalence may be higher because ZES is often undetected with routine testing. ZES should be suspected in patients who present with persistent or complex duodenal or postsurgical ulcer, especially if accompanied by esophagitis, diarrhea, weight loss, and/or liver metastases. Twenty percent of ZES patients have multiple endocrine neoplasia type I, some of whom may also have elevated levels of serum calcium and a family history of ZES. Diagnostic tests include fasting serum gastrin concentration, gastric secretion analysis, with, if necessary, secretin stimulation of serum gastrin. Complete surgical tumorectomy for cure is impossible in as many as 70-90% of patients with ZES, who then require long-term medical therapy to reduce acid exposure. Basal acid output needs to be maintained at < 5 mEq/h for uncomplicated ZES and at < 1-2 mEq/h for complicated ZES or postgastrectomy. Proton pump inhibitors (omeprazole, lansoprazole) with careful clinical monitoring provide safe and effective acid control in patients with ZES.