Normally, the muscles of the stomach, which are controlled by the vagus nerve, contract to break up food and move it through the gastrointestinal (GI) tract. The GI tract is a series of hollow organs joined in a long, twisting tube from the mouth to the anus. The movement of muscles in the GI tract, along with the release of hormones and enzymes, allows for the digestion of food. Gastroparesis can occur when the vagus nerve is damaged by illness or injury and the stomach muscles stop working normally. Food then moves slowly from the stomach to the small intestine or stops moving altogether.
The problems of gastroparesis can include:
- severe dehydration due to persistent vomiting
- gastroesophageal reflux disease (GERD), which is GER that occurs more than twice a week for a few weeks; GERD can lead to esophagitis— irritation of the esophagus
- bezoars, which can cause nausea, vomiting, obstruction, or interfere with absorption of some medications in pill form
- difficulty managing blood glucose levels in people with diabetes
- malnutrition due to poor absorption of nutrients or a low calorie intake
- decreased quality of life, including work absences due to severe symptoms
Most people diagnosed with gastroparesis have idiopathic gastroparesis, which means a health care provider cannot identify the cause, even with medical tests. Diabetes is the most common known cause of gastroparesis. People with diabetes have high levels of blood glucose, also called blood sugar. Over time, high blood glucose levels can damage the vagus nerve. Other identifiable causes of gastroparesis include intestinal surgery and nervous system diseases such as Parkinson’s disease or multiple sclerosis. For reasons that are still unclear, gastroparesis is more commonly found in women than in men.
The most common symptoms of gastroparesis are nausea, a feeling of fullness after eating only a small amount of food, and vomiting undigested food—sometimes several hours after a meal. Other symptoms of gastroparesis include
- gastroesophageal reflux (GER), also called acid reflux or acid regurgitation—a condition in which stomach contents flow back up into the esophagus, the organ that connects the mouth to the stomach
- pain in the stomach area
- abdominal bloating
- lack of appetite
Symptoms may be aggravated by eating greasy or rich foods, large quantities of foods with fiber—such as raw fruits and vegetables—or drinking beverages high in fat or carbonation. Symptoms may be mild or severe, and they can occur frequently in some people and less often in others. The symptoms of gastroparesis may also vary in intensity over time in the same individual. Sometimes gastroparesis is difficult to diagnose because people experience a range of symptoms similar to those of other diseases.
Gastroparesis is diagnosed through a physical exam, medical history, blood tests, tests to rule out blockage or structural problems in the GI tract, and gastric emptying tests. Tests may also identify a nutritional disorder or underlying disease. To rule out any blockage or other structural problems, the health care provider may perform one or more of the following tests:
- Upper gastrointestinal (GI) endoscopy. This procedure involves using an endoscope—a small, flexible tube with a light—to see the upper GI tract, which includes the esophagus, stomach, and duodenum—the first part of the small intestine. The test is performed at a hospital or outpatient center by a gastroenterologist—a doctor who specializes in digestive diseases. The endoscope is carefully fed down the esophagus and into the stomach and duodenum. A small camera mounted on the endoscope transmits a video image to a monitor, allowing close examination of the intestinal lining. A person may receive a liquid anesthetic that is gargled or sprayed on the back of the throat. An intravenous (IV) needle is placed in a vein in the arm if general anesthesia is given. The test may show blockage or large bezoars—solid collections of food, mucus, vegetable fiber, hair, or other material that cannot be digested in the stomach—that are sometimes softened, dissolved, or broken up during an upper GI endoscopy.
- Upper GI series. An upper GI series may be done to look at the small intestine. The test is performed at a hospital or outpatient center by an x-ray technician, and the images are interpreted by a radiologist—a doctor who specializes in medical imaging. Anesthesia is not needed. No eating or drinking is allowed for 8 hours before the procedure, if possible. If the person has diabetes, a health care provider may give different instructions about fasting before the test. During the procedure, the person will stand or sit in front of an x-ray machine and drink barium, a chalky liquid. Barium coats the small intestine, making signs of gastroparesis show up more clearly on x rays. Gastroparesis is likely if the x ray shows food in the stomach after fasting. A person may experience bloating and nausea for a short time after the test. For several days afterward, barium liquid in the GI tract causes stools to be white or light colored. A health care provider will give the person specific instructions about eating and drinking after the test.
- Ultrasound. Ultrasound uses a device, called a transducer, that bounces safe, painless sound waves off organs to create an image of their structure. The procedure is performed in a health care provider’s office, outpatient center, or hospital by a specially trained technician, and the images are interpreted by a radiologist; anesthesia is not needed. The images can show whether gallbladder disease and pancreatitis could be the cause of a person’s digestive symptoms, rather than gastroparesis.
- Gastric emptying scintigraphy. The test involves eating a bland meal—such as eggs or an egg substitute—that contains a small amount of radioactive material. The test is performed in a radiology center or hospital by a specially trained technician and interpreted by a radiologist; anesthesia is not needed. An external camera scans the abdomen to show where the radioactive material is located. The radiologist is then able to measure the rate of gastric emptying at 1, 2, 3, and 4 hours after the meal. If more than 10 percent of the meal is still in the stomach at 4 hours, the diagnosis of gastroparesis is confirmed.
- SmartPill. The SmartPill is a small electronic device in capsule form. The SmartPill test is available at specialized outpatient centers. The images are interpreted by a radiologist. The device is swallowed and moves through the entire digestive tract, sending information to a cell-phone-sized receiver worn around the person’s waist or neck. The recorded information provides a detailed record of how quickly food travels through each part of the digestive tract.
- Gastric emptying breath test. With this test, the person eats a special test meal that includes a natural material with a special type of carbon in it. Then, breath samples are taken over a period of several hours to measure the amount of the material in the exhaled breath. The results allow the health care provider to calculate how fast the stomach is emptying.
Treatment of gastroparesis depends on the severity of the person’s symptoms. In most cases, treatment does not cure gastroparesis, which is usually a chronic, or long-lasting, condition. Gastroparesis is also a relapsing condition—the symptoms can come and go for periods of time. Treatment helps people manage the condition so they can be as comfortable and active as possible.