Zollinger-Ellison syndrome is a rare condition in which one or more tumors form in your pancreas or the upper part of your small intestine (duodenum). These tumors, called gastrinomas, secrete large amounts of the hormone gastrin, which causes your stomach to produce too much acid. The excess acid then leads to peptic ulcers, as well as to diarrhea and other symptoms.
Signs and symptoms of Zollinger-Ellison syndrome may include:
- Abdominal pain
- Burning, aching, gnawing or discomfort in your upper abdomen
- Acid reflux and heartburn
- Nausea and vomiting
- Bleeding in your digestive tract
- Unintended weight loss
- Decreased appetite
The exact cause of Zollinger-Ellison syndrome remains unknown. But the sequence of events that occurs in Zollinger-Ellison syndrome is clear. The syndrome begins when a tumor (gastrinoma) or tumors form in your pancreas, duodenum or the lymph nodes adjacent to your pancreas.
Your pancreas sits behind and below your stomach. It produces enzymes that are essential to digesting food. The pancreas also produces several hormones including insulin, a hormone that helps to control your blood glucose.
Digestive juices from the pancreas, liver and gallbladder mix in the duodenum, the part of the small intestine next to your stomach. This is where digestion reaches its peak.
The tumors that occur with Zollinger-Ellison syndrome are made up of cells that secrete large amounts of gastrin, which in turn causes the stomach to produce far too much acid. The excessive acid then leads to peptic ulcers and sometimes to diarrhea.
Besides causing excess acid production, the tumors are cancerous (malignant). Although the tumors tend to grow slowly, the cancer can spread elsewhere — most commonly to nearby lymph nodes or your liver.
Association with MEN 1
Zollinger-Ellison syndrome may be caused by an inherited condition called multiple endocrine neoplasia, type 1 (MEN 1). People with MEN 1 also have tumors in the parathyroid glands and may have tumors in their pituitary glands.
About 25 percent of people who have gastrinomas have them as part of MEN 1. They may have also have tumors in the pancreas and other organs.
Your doctor will base a diagnosis on the following:
- Medical history. Your doctor will ask about your signs and symptoms and review your medical history.
- Blood tests. A sample of your blood is analyzed to see whether you have elevated gastrin levels. While elevated gastrin may indicate tumors in your pancreas or duodenum, it also can be caused by other conditions. For example, gastrin may also be elevated if your stomach isn’t making acid, or you’re taking acid-reducing medications, such as proton pump inhibitors.
You need to fast before this test and may need to stop taking any acid-reducing medications to get the most accurate measure of your gastrin levels. Because gastrin levels can fluctuate, this test may be repeated a few times.
Your doctor may also perform a secretin stimulation test. For this test, your doctor measures your gastrin levels, gives you an injection of the hormone secretin and measures gastrin levels again. If you have Zollinger-Ellison, your gastrin levels will increase even more.
- Upper gastrointestinal endoscopy. After you’re sedated, your doctor inserts a thin, flexible instrument with a light and video camera (endoscope) down your throat and into your stomach and duodenum to look for ulcers. Through the endoscope, your doctor may remove a tissue sample (biopsy) from your duodenum to help detect the presence of gastrin-producing tumors. Your doctor will ask you not to eat anything after midnight the night before the test.
- Endoscopic ultrasound. In this procedure, your doctor examines your stomach, duodenum and pancreas with an endoscope fitted with an ultrasound probe. The probe allows for closer inspection, making it easier to spot tumors.It’s also possible to remove a tissue sample through the endoscope. You’ll need to fast after midnight the night before this test, and you’ll be sedated during the test.
- Imaging tests. Your doctor may use imaging techniques such as a nuclear scan called somatostatin receptor scintigraphy. This test uses radioactive tracers to help locate tumors. Other helpful imaging tests include ultrasound, computed tomography (CT), magnetic resonance imaging (MRI).
Treatment of Zollinger-Ellison syndrome addresses the hormone-secreting tumors as well as the ulcers they cause.
Treatment of tumors
An operation to remove the tumors that occur in Zollinger-Ellison requires a skilled surgeon because the tumors are often small and difficult to locate. If you have just one tumor, your doctor may be able to remove it surgically, but surgery may not be an option if you have multiple tumors or tumors that have spread to your liver. On the other hand, even if you have multiple tumors, your doctor still may recommend removing a single large tumor.
In some cases, doctors advise other treatments to control tumor growth, including:
- Removing as much of a liver tumor as possible (debulking)
- Attempting to destroy the tumor by cutting off the blood supply (embolization) or by using heat to destroy cancer cells (radiofrequency ablation)
- Injecting drugs into the tumor to relieve cancer symptoms
- Using chemotherapy to try to slow tumor growth
- A liver transplant
Treatment of excess acid
Excess acid production can almost always be controlled. Medications known as proton pump inhibitors are the first line of treatment. These are effective medications for decreasing acid production in Zollinger-Ellison syndrome.
Proton pump inhibitors are powerful drugs that reduce acid by blocking the action of the tiny “pumps” within acid-secreting cells. Commonly prescribed medications include lansoprazole (Prevacid), omeprazole (Prilosec, Zegerid), pantoprazole (Protonix), rabeprazole (Aciphex) and esomeprazole (Nexium).
Long-term use of prescription proton pump inhibitors, especially in people age 50 and older, has been associated with an increased risk of fractures of the hip, wrist and spine, according to the Food and Drug Administration. This risk is small and should be weighed against the acid-blocking benefits of these medications.
Octreotide, a medication similar to the hormone somatostatin, may counteract the effects of gastrin and be helpful for some people.