|
Indigestion is a general term used by many patients to describe upper gastrointestinal discomfort and is often associated with the intake of food. The term may not be used to describe the same symptoms from patient to patient, and it is necessary for the physician to ascertain the precise description of the complaint. To some patients, indigestion refers to actual abdominal pain or pressure, which may be associated with postprandial fullness, early satiety, nausea, or bloating, and which is generally termed dyspepsia.(1) Other patients may use the term to describe a feeling of incomplete digestion or intolerance to certain foods. Yet another may use indigestion to describe belching, a feeling of gaseousness, or flatulence.
In patients with a complaint of chronic, repetitive eructation (belching), each belch is often observed to be preceded by a large gulp of air. Most of the air passes only part way down the esophagus and then is regurgitated. Aerophagia, or air swallowing, is what generally causes excessive belching, not the production of gas in the stomach or intestine. A degree of aerophagia occurs in normal individuals, but some patients gulp air excessively. Some causes include chronic anxiety, rapid eating, drinking carbonated beverages (or any beverage through a straw), gum chewing, sucking on hard candy, smoking cigarettes, poorly fitting dentures, postnasal drip, or esophageal speech.
About 20-60 percent of intestinal gas is swallowed air. Because nitrogen and oxygen are the only gases present in the atmosphere in appreciable concentrations, and because they are not produced in the gastrointestinal tract, their detection on chromatographic analysis of intestinal gas indicates that swallowed air is the source.(1) When swallowed air is not eructated, it passes into the stomach and intestine, giving a feeling of fullness and pressure. Upon x-ray, a large amount of air may be seen in the gastric fundus. This symptom complex is known as the magenblase (e.g., gastric bubble) syndrome, and may occur when a patient lies supine after a meal, allowing air to become trapped below the gastroesophageal junction by overlying fluid. Inability to eructate is also thought to cause the "gas-bloat" syndrome observed after surgical repair of a hiatal hernia.
Many patients feel that the feelings of abdominal pain and bloating they experience is due to production of excessive gas. Studies have shown that such patients actually have a normal quantity of intestinal gas, but have either a motility disturbance, or they have a visceral hypersensitivity that causes them to perceive pain or pressure with normal amounts of intestinal gas.
The average individual normally has 150 to 300ml of gas or less in the stomach and colon at any one time.(2) The amount expelled in average individuals is 476 to 1,491ml daily.(3, 4) Clues to the causes of excessive flatulence can come from analysis of the gases. Gas originates from swallowed atmospheric air, bicarbonate neutralization of stomach acids, diffusion of gases into the intestine from the blood, and bacterial fermentation.(5) The principle gases produced are hydrogen and carbon dioxide. There are minute quantities of gases such as indoles, skatols, and sulfur containing compounds that give flatus its characteristic odor. About one-third of the population produces methane.
An increase in intraluminal gas is produced by the ingestion of certain foods, particularly the legumes, and some grains. These foods contain significant quantities of nonabsorbable complex carbohydrates that pass into the colon, providing an excellent substrate for gas-producing bacteria. The best studied of these foods is beans, which contain oligosaccharides that cannot be broken down in the small bowel, but pass into the colon and are metabolized by colonic bacteria. Fructose, a natural or added sweetener
|
