The tumor secretes a hormone known as gastrin, and this results in an overproduction of hydrochloric acid in the stomach.
The patient will have severe, recurrent ulcers of the esophagus, stomach and the duodenum and jejunum, which are the upper portions of the small intestine.
Gastrinomas that result in Zollinger-Ellison syndrome occasionally stem from other organs in the body, for example, the lymph nodes, stomach, liver, and ovaries.
Most cases are new, but 25 percent to 30 percent of cases are linked to another condition, called multiple endocrine neoplasia type 1, or MEN1.
The signs and symptoms of Zollinger-Ellison syndrome include:
- Discomfort in the upper abdomen
- Burning and aching sensation in the upper abdomen
- Bleeding in the digestive tract
- General weakness
- Melaena, or black, "tarry" feces, resulting from bleeding in the digestive tract
- Unintentional weight loss
- Heartburn, or gastroesophageal reflux, when gastric acid and food from the stomach backs up into the esophagus. Symptoms may sometimes be severe.
The signs and symptoms are similar to those of a peptic ulcer. Most patients with Zollinger-Ellison syndrome have multiple tumors in the endocrine system, as well as tumors in the pancreas.
It is not clear exactly what causes Zollinger-Ellison syndrome, nor the gastrinomas that characterize it.
Gastrinomas release excessive quantities of gastrin, resulting in too much gastric acid in the stomach and duodenum. This eventually causes peptic ulcers to form in the lining of the duodenum. This often results in multiple ulcers that may cause pain or upper gastrointestinal bleeding.
As well as causing excess acid production, the gastrinomas may be malignant, or cancerous. The cancer can spread to other parts of the body, most commonly to nearby lymph nodes or the liver.
Some cases of the syndrome are caused by a genetic disorder known as multiple endocrine neoplasia type 1, or MEN 1. MEN1 is a genetic syndrome that causes multiple endocrine cancers.
It is inherited in an autosomal dominant manner, which means that if a parent is affected, they have a 50 percent chance of passing the condition to the next generation.
An individual may be at risk for developing a gastrinoma if they have had several family members with endocrine cancers, or if they have a family member with MEN1.
A physician will ask the patient about their symptoms and medical history, and a number of tests may be carried out.
Raised levels of gastrin in the blood may indicate that there are tumors in the pancreas or duodenum.
Before the blood test, the patient should be fasting, and they should refrain from using acid-reducing medications for a time that will be specified by the physician.
The blood test may need to be repeated at least three times, as gastrin levels may fluctuate.
Stomach acidity level
Patients with chronic stomach inflammation, and those who have recently undergone stomach surgery, may have high levels of gastrin in the blood, even if the stomach does not produce much acid.
It is important for the doctor to find out which condition is causing high gastrin levels. The acidity of the stomach may be tested.
If stomach acidity levels are not high, then it is highly unlikely the patient has Zollinger-Ellison syndrome.
If the stomach is making acid, a secretin stimulation test may be done. The doctor measures gastrin levels and then injects the hormone secretin, followed by another measurement of gastrin levels. If gastrin levels rise even further, this indicates that Zollinger-Ellison is present.
Upper gastrointestinal endoscopy
Also known as upper endoscopy, upper GI endoscopy or esophagogastroduodenoscopy (EGD), this test involves looking into the esophagus, stomach, and duodenum with an endoscope.
An endoscope is a lighted optical instrument with a video camera. It is used to look at the esophagus, stomach, and first part of the duodenum.
The doctor inserts the endoscope down the patient's throat and into the stomach and duodenum to look for ulcers.
During this procedure a biopsy, or tissue sample, may also be taken from the duodenum. The sample will be checked for gastrin-producing tumors.
The patient will need to fast for a specified period before this procedure.
Endoscopic ultrasound involves using an endoscope to insert an ultrasound device inside the patient. The doctor can observe the inside of the stomach and the duodenum. An internal ultrasound helps to pinpoint tumors and take tissue samples. Patients must fast for some time before this procedure.
Angiography can help to find tumors in the pancreas. A catheter is guided through the bloodstream to blood vessels located in the pancreas. A dye is then injected into the blood vessel through the catheter, as a contrast material. The dye shows up on X-ray images, highlighting blood vessels, as these tend to be denser inside tumors.
Treatment for Zollinger-Ellison syndrome focuses on the tumors and ulcers.
Doctors will usually treat the tumors first.
Tumors can be difficult to remove, because they tend to be small and hard to find. A single tumor might be surgically removed, but if there are several tumors, or if they have spread over the liver, surgery may not be possible.
Sometimes a surgeon will remove a single large tumor, even if several tumors are present.
Other treatment options to stop tumor growth may include:
- Chemotherapy, to slow down the rate of growth of tumors
- Removing part of the liver, if necessary
- Embolization, or cutting of the blood supply to the tumor
- Injecting drugs directly into the tumor.
In addition to these therapies, octreotide may be used to control symptoms. Octreotide is a medication that can reduce gastrin production. Deleted liver transplantation and RT, is a possibility, but this is still under investigation.
Excess acid in the stomach can cause discomfort and trigger ulcers.
Since the end of the 1970s, improved medications have become available to control acid production and ulcers. Before that, radical surgery was common. Procedures included severing the nerves that promote acid secretion, or even surgically removing the whole stomach.
The first line of treatment for excess acid treatment is a proton pump inhibitor (PPI). This is a type of drug that helps to control excess acid production. PPIs reduce acid by blocking the action of tiny pumps inside acid-secreting cells.
Examples of PPIs include esomeprazole (Nexium), omeprazole (Prilosec), lansoprazole (Prevacid), pantaprazole (Protonix), and rabeprazole (Aciphex).
If stomach acid levels drop, the peptic ulcers have a better chance to heal, and there will be fewer symptoms of Zollinger-Ellison syndrome.
If a patient has a peptic ulcers, the doctor may suggest surgery. An operation may be carried out to close any perforation in the wall of the stomach or duodenum that has caused by an ulcer, to remove a blockage caused by an ulcer, or to stop bleeding.
Most cases of Zollinger-Ellison syndrome are sporadic. That is, they are new occurrences in the body and cannot be predicted.
So far, there is no evidence that diet affects the risk of developing the syndrome.
How the digestive system works
Zollinger Ellison syndrome leads to an excess of acid in the stomach.
The stomach, duodenum, and pancreas are digestive organs. The stomach and the pancreas secrete gastrin that stimulates the production of gastric acid and other digestive juices that help to break down food.
The gastrin travels in the bloodstream and signals to other stomach cells to release gastric acid to help break down food.
When the food is partially digested, it moves into the duodenum, which is the first part of the small intestine. There it is broken down further. The small intestine is the tube-shaped organ between the stomach and the large intestine.
In a healthy system, the stomach cells control how much gastrin is produced, and this prevents excessive quantities of gastric acid from forming. In Zollinger-Ellison syndrome, there can be a disruption in the balance, because the gastrinomas produce extra gastrin.