Belching is the expulsion of air from the upper GI tract. It occurs in everyone and is a normal physiologic process that decreases the volume of gas in the upper stomach. With each swallow, or when drinking a carbonated beverage air is ingested and conveyed to the stomach. The swallowed air stays in the stomach because there is a muscle called the lower esophageal sphincter (LES) at the esophagogastric junction (EGJ), which remains contracted most of the time. This closes the passage between the esophagus and stomach so air cannot go back up the esophagus. Accumulation of gastric air stretches the top of the stomach and sets off a reflex that causes a relaxation of LES. This relaxation is called the transient LES relaxation (tLESR). Gastric air can then move back up into the esophagus. When it distends the top of the esophagus, a second reflex is triggered that relaxes a muscle called the upper esophageal sphincter (UES), which partitions the throat from the esophagus. The air then leaves the esophagus to fill the mouth and be expelled. This type of belch is called the gastric belch. Transient LES relaxations are also important because when they are too frequent they are a major cause of gastroesophageal reflux disease.
This type of belching is usually solitary, not bothersome and can usually be diagnoses by history. They can also be diagnosed with a test called impedance/pH testing, which allows us to track the movement of air and fluids in the esophagus over a 24-hour period. The gastric belch is seen using this technique as air moving up the esophagus from the stomach.
Ways to decrease this type of belching include eating and drinking more slowly, avoiding chewing gum and hard candies, not drinking carbonated beverages, stop smoking and treat gastroesophageal reflux disease when it is present.
Some patients complain of episodes of repeated belching. The belches might occur every few seconds for varying lengths of time. During consultation with the doctor, it is often observed. It usually stops while the patient is talking, or if they are distracted from the belching. Patients who suffer from this type of belching almost always have what is called supragastric belching. This type of belch is often associated with anxiety disorder and frequently worsens under stress. It has also been observed in patients with anorexia nervosa and obsessive compulsive disorder.
During episodes of supragastric belching the patient repeatedly uses the diaphragm to pull air into the esophagus. The air does not enter the stomach because the LES muscle does not relax. Instead, it is pushed back up the esophagus and is expelled. This pattern can repeat every few seconds for varying periods of time. While supragastric belching is easily diagnoses when seen by an informed physician, it can be diagnosed using impedance/pH testing , which allows us to track movement of air in the esophagus. Supragastric belching is seen as repeated episodes of air moving in and out of the esophagus. Esophageal manometry is a test that measures pressures along the inside of the esophagus. With manometry, supragastric belching is seen as repeated episodes of decreased followed by increased pressure in the esophagus, which correlate with repeated movement of air in and out of the esophagus.
Supragastric belching is a learned behavior. There is little information available about treatment and there are no large controlled trials of therapy. Most doctors who see these patients start by trying to explain the mechanism by which this belching occurs, and that it is a learned response to something. Patients often are resistant to this explanation. There is some evidence that speech language pathologists knowledgeable on this topic might help retrain the patient. The same might be true of behavioral therapists. There is a small amount of evidence that baclofen, a GABA-B receptor agonist traditionally used to treat muscle spasms, might improve supragastric belching.
Rumination syndrome is defined by the Rome Criteria as persistent or recurrent regurgitation of recently ingested food into the mouth with spitting, or mastication and reswallowing. Typically, there is no nausea or retching and the behavior stops when the regurgitated material becomes acidic. While the behavior is voluntary, it is often unintentional. Why this behavior begins in not clearly known.
Rumination is initiated by contraction of the abdomen, which increases pressure in the abdomen and stomach. When the pressure becomes high enough, stomach contents are pushed up into the esophagus. Distention of the esophagus opens the UES so that the food may enter the mouth. Rumination is sometimes initiated by a true gastroesophageal reflux event or a supragastric belch.
While most cases of rumination can be diagnosed by clinical history, esophageal/impedance manometry can make the diagnosis. Esophageal impedance/manometry allows us to simultaneously record pressure and bolus movement along the length of the esophagus. Rumination is seen as a rise in stomach pressure followed by a wave of pressure moving up the esophagus. Stomach contents travel up the esophagus along with the wave of pressure.
Treatment starts by explaining of the condition and mechanisms of rumination. Behavioral therapy, and particularly, abdominal breathing techniques are central to treatment. These techniques frequently extinguish the behavior.