Zollinger-Ellison syndrome is a condition in which the patient suffers from ulcers in the upper digestive tract (that do not respond to medications), excessive gastric acid secretion and diarrhea.

Zollinger-Ellison syndrome is caused by a tumor called a gastrinoma. A gastrinoma secretes gastrin, a hormone that stimulates gastric acid secretion. Gastrinomas may arise from the duodenum (the first part of the small intestine), the pancreas and occasionally from other parts like the ovary, liver and the stomach. They usually affect people between 30 and 50 years of age. Men are more commonly affected than women. In some cases, gastrinomas may be a part of a syndrome called Multiple Endocrine Neoplasia Type 1. In this syndrome, the patient suffers from multiple tumors like pancreatic and pituitary tumors, as well as hyperparathyroidism.

Gastrinomas release a hormone called gastrin. Gastrin acts on the stomach lining and stimulates it to release excess acid. It also increases the number of acid-secreting cells lining the stomach. The increased acid secretion results in inflammation and ulcers in the stomach and lower food pipe, and diarrhea.

Tests used to diagnose Zollinger-Ellison syndrome include blood tests to check for gastrin levels, gastric acid levels and secretin test to check for acid hypersecretion. Imaging studies are used to localize the tumor.

Acid-suppressive drugs are used in the treatment of Zollinger-Ellison syndrome to prevent the adverse effects of the excess acid on the stomach lining. The gastrinoma maybe surgically removed to prevent spread of the tumor.