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|Classification and external resources|
Bloat is any abnormal gas swelling, or increase in diameter of the abdominal area.  As a symptom, the patient feels a full and tight abdomen, which may cause abdominal pain and is sometimes accompanied by increased stomach growling, or more seriously, the total lack of it.
The most common symptom associated with bloating is a sensation that the abdomen is full or distended. Rarely, bloating may be painful or cause shortness of breath.
Pains that are due to bloating will feel sharp and cause the stomach to cramp. These pains may occur anywhere in the body and can change locations quickly. They are so painful that they are sometimes mistaken for heart pains when they develop on the upper left side of the chest. Pains on the right side are often confused with problems in the appendix or the gallbladder.
One symptom of gas that is not normally associated with it is the hiccup. Hiccups are harmless and will diminish on their own; they also help to release gas that is in the digestive tract before it moves down to the intestines and causes bloating. Important but uncommon causes of abdominal bloating include ascites and tumors.
There are many causes of bloating, including: diet, irritable bowel syndrome, lactose intolerance, reflux, and constipation.
Specific medical conditions like Crohn's disease or bowel obstruction can also contribute to the amount of stomach bloating experienced.
Common causes of abdominal bloating are:
- Gastric distension
- Lactose intolerance, fructose intolerance and other food intolerances
- Food allergy
- Aerophagia (air swallowing, a nervous habit)
- Irritable bowel syndrome
- Partial bowel obstruction
- Gastric dumping syndrome or rapid gastric emptying
- Gas-producing foods
- Visceral fat
- Splenic-flexure syndrome
- Menstruation, dysmenorrhea
- Polycystic ovary syndrome and ovarian cysts
- Alvarez' syndrome, bloating of unknown or psychogenic origin without excess of gas in the digestive tract
- Massive infestation with intestinal parasites (e.g., Ascaris lumbricoides)
- Celiac disease
- Certain medications, such as phentermine
- Occurs in some due to salivary hypersecretion and dehydration.
- Ovarian cancer
Important but uncommon causes of abdominal bloating include:
- Large intra-abdominal tumors, such as those arising from cancers of the ovarian, liver, uterus and stomach
- Megacolon, an abnormal dilation of the colon caused by some diseases, such as Chagas disease, a parasitic infection
- Cardiopulmonary resuscitation procedures, due to the artificial mouth-to-mouth insufflation of air.
In animals, causes of abdominal bloating include:
- Gastric dilatation volvulus, a condition of dogs which occurs when gas is trapped inside the stomach and gastric torsion prevents it from escaping
- Ruminal tympany, a condition of ruminant animals which occurs when gas cannot escape from the rumen.
Irritable bowel syndrome
Bloating from irritable bowel syndrome (IBS) is of unknown origin but often results from an insult to the gut, and as such can overlap with infective diarrhea, celiac, and inflammatory bowel diseases (Crohn's disease and ulcerative colitis). IBS is a brain-gut dysfunction that causes visceral hypersensitivity and results in bloating in association with recurrent diarrhea (or constipation) and abdominal pain. While there is no direct treatment for the underlying pathology of IBS, the symptom of bloating can be well managed through dietary changes that prevent the over-reaction of the gastrocolic reflex. Having soluble fiber foods and supplements, substituting dairy with soy or rice products, being careful with fresh fruits and vegetables that are high in insoluble fiber, and eating regular small amounts can all help to lessen the symptoms of IBS (Van Vorous 2000). Foods and beverages to be avoided or minimized include red meat, oily, fatty and fried products, dairy (even when there is no lactose intolerance), solid chocolate, coffee (regular and decaffeinated), alcohol, carbonated beverages, especially those also containing sorbitol, and artificial sweeteners (Van Vorous 2000). IBS is most commonly found in patients around the age of 20 and is found more often in women than men. In people with IBS, the intestines squeeze too hard or not hard enough and cause food to move too quickly or too slowly through the intestines. Other terms used to describe this condition include spastic bowel, spastic colon, and irritable colon. Symptoms of the condition will worsen as a person is placed under stress, during travel, and at other times when the daily routine is tampered with. Common symptoms include bloating, constipation, abdominal cramp or pain after bowel movement, or feeling like a movement is required even after one has been completed.
Most cases of stomach bloating are due to improper diet.[medical citation needed] Gas occurs because of the bacteria in the colon and is a by-product of soluble fiber digestion. Inadequate or irregular intake of fiber and water will cause a person to experience bloating or constipation. The most common natural sources of fiber include fruits and vegetables as well as wheat or oat bran. These fibers are most likely to cause flatulence. Fiber is made by plants and is not easily digested by the human gastrointestinal tract. There are two main types of dietary fiber: soluble and insoluble fiber. Soluble fiber is prebiotic and readily fermented in the colon into gases, while insoluble fiber is metabolically inert and absorbs water as it moves through the digestive system, aiding in defecation. Most types of fiber (insoluble) are attached to body water in the intestine and increase the volume of stools.
Belching and flatulence
Gas in the gastrointestinal tract has only two sources. It is either swallowed air or is produced by bacteria that normally inhabit the intestines, primarily the colon.
Belching or burping is a universal ability that works by removing gas from the stomach through the mouth. The stomach can become bloated when too much air is swallowed during eating and drinking too quickly. As the stomach swells, belching removes the gas and alleviates the pain associated with it. Burping can also be used as a form of relief from abdominal discomfort other than too much gas in the stomach.
Flatulence or farting works much like burping, but helps the body pass gas through the anus instead of the mouth. Bacteria present in the intestinal tract cause gas to be expelled from the anus. They produce the gas as food is digested and moved from the small intestine. This gas builds up and causes swelling or bloating in the abdominal area before it is released.
A common gastrointestinal problem is constipation—infrequent bowel movements, hard stools, or strain during the movements—which causes serious cases of bloating. Since most cases of constipation are temporary, simple lifestyle changes, such as getting more exercise and increasing one's intake of fiber, can go a long way toward alleviating constipation. Some cases of constipation will continue to worsen and require unconventional methods to release the feces and reduce the amount of stomach bloating. Blood in the stool, intense pain in the abdomen, rectal pain, and unexplained weight loss should be reported to a doctor. Bloating consistently accompanies constipation, and they will not develop without an underlying cause.
Heartburn and acid reflux
Painful burning sensations in the chest that is caused by gastroesophageal reflux is known as heartburn. Reflux is the back flow of gastric acid juices from the stomach into the oesophagus. Heartburn has different triggers, including certain foods, medications, obesity, and stress. These triggers are different for each individual. Gastroesophageal reflux disease or GERD is a chronic condition that can lead to more serious complications like esophageal cancer. Treatment options are available to treat the symptoms and the condition, but there is no cure for the disease. Symptoms include burping, abdominal and stomach bloating, along with pain and discomfort. Heavy meals, lying down or bending over after eating should be avoided to help prevent reflux from occurring. The stomach bloating experienced with reflux is intense and will remain until the food is digested all the way.
Conditions that are related to bloating include constipation, lactose intolerance, and acid reflux disease. All of these conditions share the same symptoms and can share the same causative agents. These causes include unhealthy diet, smoking, alcohol consumption, low amount of exercise, and overall health. Each of these conditions can be experienced as a symptom of the others and is also a cause for each of them. In most cases where one of the conditions is present, there is at least one if not two of the others. Treatment for each condition is performed using the same medications and recommended dietary changes like increased fiber intake and reduced fat intake. If the conditions develop into disease such as gastroesophageal reflux disease or chronic constipation, additional medications will be required. Bloating and flatulence are sometimes related to constipation, and treating the underlying condition may be helpful.
There are many over-the-counter (OTC) medications that can be used to treat bloating. Food enzymes can be found in some products that will help break down the sugars found in grains, vegetables and dairy products. They can be taken before food is consumed or added to the food that causes the gas and bloating. Another type of medicine is activated charcoal tablets which decrease the odor from gas. The most common treatment is antacids. These medications have no effect on the gas that is presently in the intestines, but enable gas build-up to be belched away more easily, reducing the amount of bloating that develops. Another treatment is Simethicone, an oral anti-foaming agent that helps the body to expel the gas more quickly. Also combinations of prokinetics, such as domperidone + metoclopramide + diphenhydramine (the latter for the prevention of extrapyramidal reactions, especially acute dystonic reactions) + proton pump inhibitors (PPIs), have dramatic effects on bloaters and belchers especially.
There are several things that can be done to relieve the pressure in the stomach. Taking a walk after eating a meal is a good way to nudge the contents of the bowels along. Exercising releases hormones that work to encourage activity in the bowels. Foods like bubble gum or bubbly beverages also cause a build-up of air that results in excessive gas and bloating, as does smoking. There are also certain types of vegetables and fruits that contain types of starches which are poorly digested by people but well digested by bacteria.
- Abdominal bloating, National Institutes of Health, Retrieved November 7, 2013
- Gas and Gas Pains Mayo Clinic. Retrieved on 2010-01-26
- Abdominal Bloating MedLine Plus. Retrieved on 2010-01-26
- Irritable Bowel Syndrome: Tips on Controlling Your Symptoms Family Doctor. Retrieved on 2010-01-19
- Fiber And Increased Gas MedicineNet. Retrieved on 2010-01-19
- What Causes Flatulence MedicineNet. Retrieved on 2010-01-19
- Constipation Definition Mayo Clinic Retrieved on 2010-01-19
- Belching Bloating and Flatulence American College of Gastroenterology. Retrieved on 2010-01-26
- Partly based on Abdominal bloating. MedlinePlus (US public domain Medical Encyclopedia). Update Date: 10 November 2004. Updated by: Christian Stone, M.D., Division of Gastroenterology, Washington University in St. Louis School of Medicine, St. Louis, MO. Review provided by VeriMed Healthcare Network. Ahmed Shazly.
- Van Vorous, Heather. Eating for IBS. 2000. ISBN 1-56924-600-9. Excerpted with author's permission at Help for Irritable Bowel Syndrome (see IBS Diet Section)