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Abdominal distension occurs when substances, such as air (gas) or fluid, accumulate in the abdomen causing its outward expansion beyond the normal girth of the stomach and waist. It is typically a symptom of an underlying disease or dysfunction in the body, rather than an illness in its own right. People suffering from this condition often describe it as "feeling bloated." Sufferers often experience a sensation of fullness, abdominal pressure and possibly nausea, pain or cramping. In the most extreme cases, upward pressure on the diaphragm and lungs can also cause shortness of breath. Through a variety of causes (see below), bloating is most commonly due to buildup of gas in the stomach, small intestine or colon. The pressure sensation is often relieved, or at least lessened, by burping (belching) or passing gas (flatulence). Medications that settle gas in the stomach and intestines are also commonly used to treat the discomfort and lessen the abdominal distension.
Experts believe that a major cause of abnormal bloating is excessive eating and air swallowing, known as aerophagia. Other causes of bloating include inflammatory bowel diseases such as Crohn's disease and ulcerative colitis, irritable bowel syndrome, diabetes, functional dyspepsia or transient constipation. In rare cases, bloating may occur in individuals who have milk intolerance (lactose intolerance), parasite infections like giardia, food poisoning (bacteria), celiac disease, severe peptic ulcer disease, bowel obstruction or after certain types of abdominal surgery.
Heart failure and cirrhosis are also a common cause of distension. In both of these disorders, fluid accumulates in the abdomen and creates a sensation of fullness. Abdominal distension can also be a symptom of ovarian cancer. Women are more prone to bloating and often identify these symptoms during menstruation. Some individuals who develop distension may have either poor motility of their intestines or may be hypersensitive to gut sensations. Certain medications, such as antidepressants and anti-spasmodics, can contribute to reduced gut motility. Studies have shown that swallowing air during eating or delayed emptying of the stomach from hyperacidity leads to bloating after a meal. Individuals who are constipated also complain of bloating. In some individuals who are hypersensitive, any volume of air may be perceived as fullness and there may not be actual abdominal distension.
Abdominal distension (or "distended abdomen") can be a sign of many other conditions, including:
- Celiac disease
- Tropical sprue
- Small bowel bacterial overgrowth syndrome
- Eosinophilic gastroenteritis
- Capillaria philippinensis
- Hookworm disease
- Whipple's disease
- Kidney stones
- Lactose intolerance
- Obstructed bowel
- Polycystic liver disease
- Premenstrual syndrome
- Weight gain
- Ovarian cancer
- Inflammatory bowel disease (Crohn's disease and ulcerative colitis)
- Pseudomonas aeruginosa infection
- Cystic fibrosis
Bloating is not life-threatening. In most cases, bloating can be handled with simple home remedies and changes in lifestyle. Persistent or recurrent bloating may be caused by intestinal parasites, other infections, or other medical conditions.
Certain foods have been known to worsen bloating. Poorly digested components of many foods are excreted into the large intestine where they are degraded by bacteria, producing excess gas. Depending on the undigested component, this may affect the odor and the volume of gas created. Excess dietary fiber intake is a known cause of belching, gas and bloating. Many vegetables are known to cause bloating due to high levels of fiber and undigestible sugars such as raffinose (e.g. beans, cabbage, broccoli).
For some people, recurrent distension symptoms worsen their quality of life and thus many resort to health supplements or medications. Dietary supplements containing various enzymes, for example Beano, are formulated to help break down complex carbohydrates and vegetables in order to reduce to substances in the gut that cause bacterial overgrowth and subsequent bloating. Though these enzymes help reduce gas and belching, they may not always reduce bloating.
Other over the counter formulas recommended for bloating include simethicone and activated charcoal. Probiotics are also used to treat bloating based on the theory that improved gut flora will improve digestion and lessen gas generation.
Antidepressants in low doses have been found to help a few individuals. These agents alter gut perception of fullness and do help relieve anxiety and apprehension.
- Intestinal gas, belching, bloating and flatulence MedicineNet. 2010-01-27
- American College of Gastroenterology. "Belching, Bloating and Flatulence" 2010-01-27.
- Goldfinger, Stephen E, MD. "Gas and bloating overview" 2010-01-27.
- "Gas in the Digestive Tract - National Digestive Diseases Information Clearinghouse". Digestive.niddk.nih.gov. Retrieved 2014-01-22.
- PediaBook.com at PediaBook.com Encyclopedia
- Overview at University of Maryland Medical Center
- MedlinePlus/NIH - Abdominal bloating
- MedlinePlus/NIH - Abdomen - swollen