Gastroparesis means “paralysis of the stomach.” Gastroparesis is a digestive disorder in which there is no abnormal gastric motility. If the person is in good health, the stomach functions normally, and the contraction of the stomach helps break down the ingested food and propels the pulverised food into the small intestine, where digestion and absorption of nutrients continue. In the presence of gastroparesis, the stomach cannot contract normally; therefore, it is not capable of grinding food and propelling it into the small intestine properly. The standard digestion process might not take place.
Causes for gastroparesis
There are many causes of gastroparesis, and diabetes is one of the most common diseases. Other causes include infections, endocrine system disorders, connective tissue disorders such as scleroderma, neuromuscular diseases, idiopathic (unknown) causes, cancer, radiation treatment to the chest or abdomen, and some types of chemotherapy, and intestinal tract surgery higher. In addition, any surgery performed on the oesophagus, stomach, or duodenum could injure the vagus nerve. The vagus nerve is responsible for many gut sensory and motor (muscular) responses. When the person is healthy, the vagus nerve sends impulses through neuro-transmitters to the smooth muscle of the stomach to produce a contraction and propel the gastric contents. If the vagus nerve is injured during an operation, gastric emptying may not occur. Symptoms of postoperative gastroparesis may develop immediately or even years after surgery.
On the other hand, medications could cause delayed gastric emptying, similar to the symptoms of gastroparesis. This is especially common with narcotics that control pain, calcium channel blockers, and certain antidepressants. Therefore, it is important to record the names of all medications and take the list with you when you see your doctor evaluate your GI symptoms. In addition, people who suffer from eating disorders, such as anorexia nervosa or bulimia, may also develop gastroparesis. Fortunately, gastric emptying is restored, and symptoms improve when food intake and feeding times are normalised.
What are the symptoms of gastroparesis?
Symptoms of gastroparesis include bloating, nausea, premature fullness while eating, heartburn, and epigastric pain. Eating solid foods, high-fibre foods such as fruits and vegetables, fatty foods, and highly carbonated or high-fat beverages may also cause symptoms. The most common symptom is probably early satiety, a feeling of fullness that occurs shortly after starting to eat. Nausea and vomiting are also common. People with gastroparesis may regurgitate or vomit undigested food many hours after their last meal. In addition, the person may lose weight due to poor absorption of nutrients or because they use too few calories.
How is gastroparesis diagnosed?
A history of early satiety, bloating, nausea, regurgitation, or vomiting with meals would normally prompt an evaluation to determine the cause of the symptoms. These symptoms can also be caused by inflammation, ulceration, or obstruction due to a tumour, for which diagnostic tests would be applied to determine the reason. To exclude an obstruction, radiographic tests, endoscopic procedures, and motility tests are used to view the stomach lining and obtain biopsies, in addition to examining the pattern of muscle contraction. Below is a description of these tests.
Upper endoscopy:
In this test, a thin, flexible tube is passed through your mouth and into your stomach. The endoscope has a camera that allows the upper gastrointestinal tract to be evaluated for the presence of ulcers, inflammation, cancer, hernias, or other abnormalities. These diseases can cause symptoms similar to those of gastroparesis. Upper endoscopy usually takes 10 to 15 minutes to complete. Medications are usually given intravenously just before the exam to keep the patient comfortable and as a means of sedation. Biopsies may be obtained if anything is abnormal, such as an ulcer or inflammation.
Gastric emptying study:
This widely available nuclear medicine test studies the rate at which the stomach empties solid and liquid material. Delayed gastric emptying is indicative of diagnosing gastroparesis. The patient ingests an egg or oatmeal, along with a very small amount of radioactive material (99m Tc), and the stomach emptying process is measured with a scanning technique.
Gastric emptying scintigraphy:
Is a test that measures the volume of stomach contents before and after eating, or how well the stomach relaxes in response to eating food. This test uses minute amounts of radioactive material , which is picked up by the stomach lining to indirectly measure the volume of the stomach. The patient consumes a nutritional drink within 30 seconds. Before and after consuming the healthy drink, the patient passes through the scanner to observe the stomach. The test indicates whether the stomach relaxes appropriately when it is full. Symptoms of poor stomach relaxation may be identical to those of poor stomach emptying, but this test helps distinguish the processes. Gastric emptying scintigraphy is not readily available.
Gastroduodenal manometry:
This test measures how well the smooth muscle of the stomach and small intestine contracts and relaxes. In this test, a thin tube is placed into the stomach, usually with the help of an endoscope. The probe is advanced into the small intestine, and over the next several hours, the patient’s fasted, and fed contractile responses are observed and recorded. The manometric probe provides information about the force and frequency with which the stomach muscles are contracting and indicates whether there is coordination between the contractions of the stomach and those of the small intestine. To diagnose gastroparesis, gastroduodenal manometry may be helpful, although it is not usually required. This exam is not available everywhere.
X-ray of the small intestine:
This consists of a contrast-enhanced X-ray used to delineate the anatomy of the small intestine. This study is not usually needed to establish the diagnosis of gastroparesis. Still, a blockage in any part of the small intestine would result in the accumulation of material and explain the delay in gastric emptying. An obstruction in the small intestine could cause symptoms similar to gastroparesis, but the treatment would be different. Treatment for bowel obstruction is to allow the bowel to rest completely until the reason for the obstruction, such as inflammation, resolves or surgery, is performed to remove the blockage.
Importance of nutrition as a treatment for gastroparesis
Diet is one of the main treatments for those suffering from gastroparesis. The stomach digests some foods more easily than others. Fatty foods take longer to digest than fibrous foods like raw vegetables. Therefore, people with gastroparesis should lower their fibre intake or avoid these foods. In case of eating fibre, they should chew it well and cook it until it is soft. Poorly digested food can collect in the stomach and form what is known as a bezoar. This mass of undigested matter could cause a blockage and prevent the stomach from emptying, leading to nausea and pain. In that case, it would be necessary to use endoscopic instruments to separate and remove the bezoar. Fortunately, even when gastric emptying is greatly impeded, the person tolerates typically thick and clear liquids (for example, pudding or nutritional drinks), which pass through the stomach. In addition, many people with gastroparesis can lead relatively everyday lives with the help of liquid dietary supplements and soft foods, the consistency of pudding, or blended solid foods. When gastric paralysis is severe, or the person cannot be controlled with a soft or blended diet, feeding tubes may need to be placed into the small intestine (jejunostomy). These feeding tubes are usually placed through endoscopy or surgery through the skin, directly into the small intestine (Figure 1). Before placing a feeding tube, A trial with a temporary orojejunal or nasojejunal feeding tube is first done for a few days to check the person’s tolerance for this type of direct feeding into the small intestine. Usually, the temporary feeding tube is placed with the help of an endoscope, which guides the tube from the nose or mouth to the oesophagus (the tube that connects the mouth to the stomach) and then to the stomach to finally reach the intestine thin.
Medications prescribed for gastroparesis
It is important to realize that medications prescribed for various conditions may have side effects that cause gastroparesis. Among the drugs that most commonly delay stomach emptying are narcotics and some antidepressants.
Few medications are available or approved for treating gastroparesis, and their use may be limited due to unpleasant side effects and poor efficacy. Among the drugs available are metoclopramide, erythromycin, Cisapride, domperidone and tegaserod.
Metoclopramide:
Is a drug that acts on dopamine receptors in the stomach and intestine, as well as in the brain. This medication can stimulate stomach contractions and lead to better emptying. This drug also has the potential to act on the part of the brain that controls the gag reflex and, therefore, might decrease feelings of nausea and the urge to vomit. Some people have limited use of this drug because of the side effects of agitation and facial twitching, or “tardive dyskinesia.” Metoclopramide can also cause painful breast swelling and nipple discharge in both men and women. This drug is not recommended for long-term use.
Domperidone:
Is another drug that acts on dopamine receptors. Domperidone is not available in the United States, although it is used in Mexico, Canada, and some European countries.
Erythromycin:
Is a commonly used antibiotic that binds to some small intestine and stomach receptors, known as “motilin receptors”. Stimulation of motilin receptors results in contractions and better stomach emptying. The beneficial effect of erythromycin may be short-lived because those who take it often have a high chance of developing tolerance to it. It is possibly best for erythromycin to be taken when symptoms are worse or irregularly, so there is less chance of developing tolerance.
Cisapride binds to serotonin receptors in the stomach wall, causing the smooth muscle of the stomach to contract and improve gastric emptying. In the late 1990s, Cisapride was withdrawn from the market due to complications of cardiac arrhythmias, discovered in patients with a history of arrhythmia or coronary artery disease using this remedy. Now, it is available again, although its use is restricted. Therefore, people with underlying kidney or heart disease should not take Cisapride.
New remedies
Medications approved to treat other motility disorders offer some hope in treating gastroparesis. Tegaserod is an approved remedy for patients suffering from constipation-predominant irritable bowel syndrome. Tegaserod binds to a special serotonin receptor in the intestinal wall. It has already been shown to accelerate the emptying the stomach, small intestine, and colon in people with irritable bowel syndrome. Clinical trials are now underway in people with diabetic gastroparesis to determine if it increases gastric transit and reduces symptoms in this condition.
Octreotide, a drug sometimes used to treat diarrhoea, was shown in a small study to speed up gastric emptying in patients with scleroderma. In a study involving normal volunteers, octreotide caused a decrease in the uncomfortable feeling of fullness after eating. This suggests that octreotide might benefit people with gastroparesis, although further study is needed before it can be recommended as a safe and effective treatment.
Surgery for gastroparesis
Surgery for gastroparesis is reserved for people with severe and refractory symptoms, medication intolerance, or poor nutrition due to their disease. Placement of gastric decompression tubes could reduce symptoms and hospitalizations in those who experience recurrent vomiting and dehydration. Various tubes, including gastrostomy buttons and percutaneous tubes, can remove air trapped within a poorly contracted stomach. The double lumen gastrostomy tube allows it to do two things: remove air from the stomach and supplement nutrition directly to the small intestine. The percutaneous jejunostomy tube is used to supplement nutrition. In some cases, the lower stomach is stapled or bypassed, and the small intestine is reconnected to the remaining stomach to improve the emptying of stomach contents. Rarely is the stomach completely removed.
Gastric electrical stimulation
An area that generates a lot of interest and research is using electrical stimulation to improve gastrointestinal activity. This technique uses electrodes, surgically or endoscopically attached to the stomach wall, which, when stimulated, trigger contractions in the stomach and increase the emptying rate. However, few studies have shown that gastric stimulation or “pacing” returns normality to disordered gastric motility and reduces symptoms of nausea and vomiting in patients with gastroparesis. Future studies will help determine who would benefit most from this procedure. Only a few centres in the country perform these gastric stimulation procedures.
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