March 25, 2011
Dear Mayo Clinic:
What would cause a stomach to empty very slowly?
Problems with stomach emptying (gastroparesis) occur when stomach muscles don't work correctly. Although the underlying cause can't always be found, damage to pacemaker cells and nerves in the stomach due to diabetes or surgery can lead to stomach muscle dysfunction. Medications may also cause the stomach to empty slowly.
For food to move through the stomach, first the muscles at the top of the stomach must work appropriately — relaxing to allow food into the stomach where it is stored. Then, muscles in the middle and lower part of the stomach need to contract to break food down before it can move out of the stomach into the small intestine. Finally, there needs to be coordination between the muscles of the stomach and small intestine. If any of those processes go wrong, the stomach will empty more slowly than normal.
In many cases the underlying cause of problems with stomach emptying isn't known (idiopathic gastroparesis). Researchers suspect that one source of idiopathic gastroparesis could be the aftermath of an infection. But that hasn't been proven. There are three main known causes of gastroparesis: diabetes, surgery and medication.
Diabetes can lead to gastroparesis in several ways. First, the disease can damage nerves within the stomach, as well as nerves that send signals from the brain to the stomach, disrupting the stomach muscles' ability to function.
Second, diabetes can damage cells located between the nerve endings and smooth muscle cells in the gastrointestinal (GI) tract. These cells, called the interstitial cells of Cajal (ICC), serve as a pacemaker for GI muscles, including those of the stomach. ICC send out signals that regulate the strength and frequency of GI muscle contractions. When these cells are damaged, the stomach can't contract correctly and stomach emptying is delayed. Loss of ICC is the most common defect in delayed stomach emptying due to diabetes. Many people with idiopathic gastroparesis also have ICC damage.
Third, recent research has shown that in some people with diabetes, immune cells within the stomach wall are activated, and that can result in delayed gastric emptying.
Surgery can also lead to problems with stomach emptying if it changes the anatomy of the stomach or alters the stomach nerves. A variety of medications may result in gastroparesis, as well. The most common are pain medications, particularly opioid analgesics.
If the doctor suspects gastroparesis — based on symptoms such as nausea, vomiting, a feeling of fullness after eating small amounts of food, abdominal pain and weight loss — a gastric emptying test can confirm the diagnosis. This test measures how long it takes for food to move through the stomach. There are several ways to measure stomach emptying. In the most common test, a person eats food that contains a tiny amount of radioactive material. A scanner that detects the material is placed over the person's abdomen to monitor food movement and the rate at which food leaves the stomach.
If gastroparesis is caused by medication, the doctor may be able to change the prescription to a drug that doesn't affect stomach emptying. Medication to stimulate stomach muscles may be helpful, but these drugs can have side effects. Medication can also help control nausea, vomiting and other symptoms. Rarely, more invasive procedures and devices may be used to treat gastroparesis.
For many people, dietary changes such as eating more frequent, smaller meals low in fiber can help lessen the symptoms of gastroparesis significantly. If diabetes is the cause, better glucose control may also help.
Anyone who is dealing with stomach emptying problems should find a physician who has experience with gastroparesis and has access to a strong support team, including nutrition experts. This type of specialist will be best able to accurately diagnose the condition and develop a treatment plan, including referral to a dietitian who is familiar with dietary changes that can make living with gastroparesis easier.
— Gianrico Farrugia, M.D., Gastroenterology, Mayo Clinic, Rochester, Minn.