Zollinger-Ellison syndrome is caused by tumors usually found in the head of the pancreas and the upper small bowel. These tumors produce the hormone gastrin and are called gastrinomas. High levels of gastrin cause overproduction of stomach acid.

High acid levels lead to multiple ulcers in the stomach and small bowel. Patients with Zollinger-Ellison syndrome may experience abdominal pain and diarrhea. The diagnosis is also suspected in patients without symptoms who have severe ulceration of the stomach and small bowel.

Gastrinomas may occur as single tumors or as multiple, small tumors. About one-half to two-thirds of single gastrinomas are malignant tumors that most commonly spread to the liver and lymph nodes near the pancreas and small bowel. Nearly 25% of patients with gastrinomas have multiple tumors as part of a condition called multiple endocrine neoplasia type I (MEN I). MEN I patients have tumors in their pituitary gland and parathyroid glands in addition to tumors of the pancreas.

• pain
• vomiting blood (occasional)
• diarrhea

• The gastrin level is increased.
• A secretin stimulation test is positive.
• A calcium infusion test is positive.
• An abdominal CT scan shows a tumor (or tumors) in the pancreas or early small bowel.
• An octreotide scan shows a tumor in the pancreas or early small bowel.

A class of acid-suppressing medications called proton pump inhibitors (for example, omeprazole, lansoprazole) is now first line treatment of Zollinger-Ellison syndrome. These drugs reduce acid production by the stomach dramatically and promote healing of ulcers in the stomach and small bowel. They also provide relief of abdominal pain and diarrhea. Another class of acid-suppressing medications called H-2 blockers may also be used (for example, cimetidine, ranitidine). The H-2 blockers are less potent than proton pump inhibitors.

Surgical removal of a single gastrinoma may be attempted if there is no evidence that it has spread to other organs (such as lymph nodes or the liver). Surgery on the stomach (gastrectomy) to control acid production is rarely necessary today.

Early diagnosis and surgical resection is associated with a cure rate of only 20% to 25%.However, gastrinomas are slow growing, and patients may live for many years after the tumor is discovered. Acid-suppressing medications are very effective at controlling the symptoms of acid overproduction.

• spread of the tumor to other organs (most often liver and lymph nodes)
• failure to locate the tumor during surgery

Call your health care provider if severe, persistent abdominal pain occurs, especially if it occurs with diarrhea.