What is gastroparesis?
Gastroparesis is a chronic medical condition of impaired gastric (stomach) motility, which results in delayed gastric emptying. It is generally a consequence of an abnormal activity of the muscles of the stomach, caused by either an altered transmission of electrical conduction throughout the stomach wall (abnormal myoelectrical activity), or a defective communication between the nerves of the stomach and the gastric muscles (neuromuscular dysfunction).
What causes gastroparesis?
Several chronic clinical conditions can cause delayed gastric emptying. The most common are diabetes and scleroderma, but it is also a consequence of certain surgical procedures, like total vagotomy for the management of gastritis. However, a significant number of patients don’t have any of these conditions and may still develop some degree of gastroparesis. In order to diagnose gastroparesis, it is very important to rule out any other causes of delayed gastric-emptying, like gastric outlet obstruction.
What are the symptoms of gastroparesis?
Patients with gastroparesis usually feel full after eating small amounts of food (early satiety), which causes some degree of abdominal discomfort after eating. They can also feel a sensation of fullness after every meal, bloating, abdominal distention and pain, nausea, vomiting, loss-of-appetite, dehydration and weight-loss. Especially these last two symptoms can put the patient’s life at risk for several metabolic and nutritional deficiencies. Some patients may even require aggressive nutritional support, either through a feeding tube placed in the small intestine, or through an intravenous catheter.
How is gastroparesis diagnosed?
The most accepted method for diagnosing gastroparesis is with a radionuclide solid food test meal. In this procedure, a small dose of a special radioactive material is added to a solid food meal. After eating this radioactive meal, a scanner is placed over the stomach to monitor the amount of radioactivity in the stomach, and measuring the rate at which the stomach empties its content. In patients with gastroparesis the delayed gastric emptying causes the radioactive meal to remain in the stomach much longer than normal.
Is the radioactive gastric emptying study safe?
Yes. This study is performed by a nuclear medicine physician following strict safety guidelines. The radioactive material is not absorbed by the body, and it is eliminated in the stool. However, pregnant women should not undergo this study to prevent exposure of radioactivity to the fetus.
Are there any other methods to detect gastroparesis?
Yes. Simple X-ray studies can be used to demonstrate abnormal emptying of a contrast material in patients with gastroparesis. It can’t detect all forms of gastroparesis, making the radionuclide-emptying test a better option. Other studies require the placement of electrodes within the stomach to measure its electrical activity and response to electrical stimulation. These studies are useful to demonstrate an abnormal electrical activity, but they do not evaluate the effects of those abnormalities on gastric emptying.
How is gastroparesis managed?
Although gastroparesis is not a curable disease, there are several options for its treatment. Treatment can be either medical or surgical, with precise indications for each type of treatment. Medical treatment relies on the combination of drugs that promote gastric emptying and dietary modifications. Drugs used for gastroparesis help promote gastric emptying and suppress the desire for vomiting. Patients are instructed to modify their diets to low-fat, low-fiber small and frequent meals with more liquids. If the patient fails to respond to medical therapy, the patient may be eligible for the surgical placement of a gastric electrical stimulator.
What is a gastric electrical stimulator?
Gastric electrical stimulators (GES) are electronic devices designed for the treatment of gastroparesis. Through differences in voltage and frequency, the GES promote the neuromuscular activity of the stomach, reducing the symptoms of gastroparesis. The device coordinates the gastric wall’s muscle contractions in a manner similar to how a cardiac pacemaker regulates the heart’s electrical activity. The modification of the gastric activity causes a significant improvement in the patient’s symptoms, tolerating food better and improving overall quality of life.
What does the gastric electrical stimulator consist of?
The implantable GES system has three main components: a pulse generator, a pair of intramuscular leads, and an external programmer. The pulse generator is a battery-powered device that controls the frequency of the gastric stimulation. The intramuscular leads are two electrodes that carry the electrical energy from the generator directly into the muscles in the gastric wall. These two devices are coupled together and require a surgical procedure for their placement. The third component, the external programmer, activates and regulates the pulse generator, so that it can be individually programmed for each patient.
How is the gastric electrical stimulator placed?
The GES requires a surgical procedure for its proper placement. Using laparoscopy (also known as “key-hole surgery”, a minimally invasive access procedure), the two electrodes are permanently sutured to the greater curvature of the stomach. During the procedure, and endoscopy is performed to ensure that the electrodes do not penetrate into the stomach. After securing them to the stomach, the electrodes are connected to the pulse generator and the generator is calibrated with the external programmer in a standard configuration. After verifying proper function, the pulse generator is then placed just below the skin in the lower left quadrant of the abdomen. An abdominal X-ray is performed to evaluate the placement of the device and for future reference. The patients are usually discharged from the hospital 24 to 48 hrs after the procedure, tolerating their normal diet.
Is it a safe procedure?
Yes. The Food and Drug Administration approved the GES in the year 2000, for the treatment of refractory diabetic or idiopathic gastroparesis. The device requires informed consent and cannot be implanted at any given institution until the local Institutional Review Board has approved its use. Contraindications for this procedure include age younger than 18 years, pregnancy, and certain physical and mental conditions.
Who are the best candidates?
Several factors are considered when considering the surgical placement of a GES for surgery. Patients with gastroparesis secondary to a known disease (e.g. diabetes), benefit more from the procedure than patients with idiopathic gastroparesis. Patients with severe abdominal pain that require continuing administration of narcotics, abdominal pain that precedes vomiting, and poorly controlled migraine headaches are less likely to benefit from the procedure, but are still candidates if medical therapy fails.
What results are expected with the gastric electric stimulator?
The surgical procedure is generally well tolerated and has minimal if any complications. After surgery, most patients show a significant clinical improvement. Although most patients still present with gastrointestinal symptoms after the procedure, all patients had a decrease in both the frequency and the intensity of those symptoms. Several patients are able to regain some of the previously lost weight, and many of them stop requiring nutritional support over time. All these positive changes translate into better quality of life.
What are the complications of the gastric electrical stimulator?
The procedure is generally well tolerated and has very low complication rate (3.7%). The most frequent complications are infection at the site of the generator, abdominal pain if the leads are in contact with the abdominal wall, detachment of the electrodes from the gastric wall, migration of the generator with electrode dislodgement.
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