Belching, Bloating, and Flatulence

4 Belching, Bloating, and Flatulence

In this chapter, belching is defined as the eructation of gas through the mouth; bloating is gaseous abdominal distention; and flatulence is the passage of intestinal gas through the rectum.


Belching is not a symptom of organic disease. The only cause of belching is the swallowing of air (aerophagia). Air is swallowed or, more accurately, sucked into the stomach and released in the form of a belch. Air swallowing may occur with eating or drinking; more air is swallowed with liquids than with solids. Aerophagia also occurs as a conscious or, more often, an unconscious nervous habit unassociated with food ingestion. It can also be associated with mouth breathing, gum chewing, orthodontic appliances, and poorly fitting dentures. Chronic, repetitive, unintentional belching is usually caused by repetitive inhalation of air and its regurgitation from the stomach or esophagus in the form of a belch. Some patients who demonstrate these findings consciously or unconsciously relax the upper esophageal sphincter during inspiration. Belching occurs in patients with dyspepsia and may be an uncommon sign of gastroesophageal reflux. It cannot be used to differentiate between them.

Bloating and Flatulence

Bloating and flatulence are two common complaints reported to physicians. The problem has been recognized since the time of Hippocrates, who taught that “passing gas is necessary to well-being.” In the days of early Rome, it was noted that “all Roman citizens shall be allowed to pass gas whenever necessary.” Because swallowed air is reabsorbed in the small bowel, most of the gas in the distal small bowel and colon is produced within the bowel by fermentation. Small-bowel bacterial overgrowth can lead to malabsorption syndrome characterized by flatulence, diarrhea, chronic abdominal pain, and bloating; symptoms are often seen in patients with irritable bowel syndrome. In most instances, flatulence is not of any clinical significance, but because various pathologic conditions may be associated with it, their presence should be investigated if the flatulence is excessive.

Bloating may be caused by gaseous distention of the stomach, small bowel, or colon. This condition occurs more frequently in patients with gastroparesis, malabsorption of various sugars and fat, and colonic bacterial fermentation of unabsorbed foods. In some patients, disturbed visceral motility and increased sensitivity to normal luminal distention may cause the sensation of bloating.

Flatulence is usually caused by excessive production of gas (in the large bowel and less frequently in the small bowel) in an otherwise normal individual or increased discomfort from normal amounts of abdominal gas in healthy individuals. If bloating and flatulence have persisted for several years without the development of signs of serious organic pathology (e.g., weight loss, ascites, jaundice), the patient can be reassured that the flatulence is not of great clinical significance. However, it must always be remembered that some patients with gallbladder disease, colon carcinoma, irritable bowel syndrome, diverticulitis, and diverticulosis may present with a chief complaint of abdominal discomfort, bloating, and, occasionally, flatulence. Patients with colon carcinoma may present with vague abdominal discomfort or distention.

Mar 21, 2018 | Posted by in BIOCHEMISTRY | Comments Off on Belching, Bloating, and Flatulence
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