Abdominal distension occurs when substances, such as air (gas) or fluid, accumulate in the abdomen causing its expansion. It is typically a symptom of an underlying disease or dysfunction in the body, rather than an illness in its own right. People with this condition often describe it as "feeling bloated". Affected people often experience a sensation of fullness, abdominal pressure, and sometimes 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 belching or flatulence. Medications that settle gas in the stomach and intestines are also commonly used to treat the discomfort and lessen the abdominal distension. Causes One of the causes of abnormal bloating is excessive eating and air swallowing, known as aerophagia. Other causes of bloating and distension 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 such as 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: Ascites Capillaria philippinensis Celiac disease Coccidiosis Cystic fibrosis Diverticulitis Eosinophilic gastroenteritis Fasciolosis Gastroparesis Giardiasis Hookworm disease Inflammatory bowel disease (Crohn's disease and ulcerative colitis) Kidney stones Kwashiorkor