What is Abdominal Pain?
The abdomen is an anatomical area that is bounded by the lower margin of the ribs above, the pelvic bone below, and the flanks on each side. Although abdominal pain can arise from the tissues of the abdominal wall that surround the abdominal cavity (i.e., skin and abdominal wall muscles), the term abdominal pain generally is used to describe pain originating from organs within the abdominal cavity (i.e., beneath the skin and muscles). These organs include the stomach, small intestine, colon, liver, gallbladder, and pancreas. Occasionally, pain may be felt in the abdomen even though it is arising from organs that are close to but not within the abdominal cavity, for example, the kidneys, and the uterus or ovaries.
Abdominal pain is caused by inflammation (e.g., appendicitis, diverticulitis, colitis), by stretching or distention of an organ (e.g., obstruction of the intestine, blockage of a bile duct by gallstones, swelling of the liver with hepatitis), or by loss of the supply of blood to an organ (e.g., ischemic colitis). To complicate matters, however, abdominal pain also can occur without inflammation, distention or loss of blood supply. An important example of this latter type of pain is irritable bowel syndrome (IBS). It is not clear what causes the abdominal pain in IBS, but it is believed to be due either to abnormal contractions of the intestinal muscles (e.g., spasm) or abnormally sensitive nerves within the intestines that give rise to painful sensations inappropriately (visceral hyper-sensitivity).
Abdominal pain can be acute, in which the question of urgent surgery arises, or it can be chronic, in which case therapy (at least for a protracted time) is medical.
Descriptions of abdominal pain have severe limitations because individuals react to pain differently. Infants and children may be unable to localize their discomfort. Obese or elderly patients tend to tolerate pain better than others, but they have difficulty localizing the pain.
The most troublesome problem in young women is pelvic inflammatory disease (PID), which is treated with antibiotics, although tubo-ovarian abscesses require operation. When symptoms are confined to the right lower quadrant, it may be difficult to determine whether a patient has PID or appendicitis.
Some ovarian cysts are small and disappear within 3 mo; others are large, may contain teeth or other solid elements, and may be subject to torsion and gangrene. Endometriosis is a common cause of pain; it is often controlled by hormones but may require operation. An ectopic pregnancy is life threatening without emergency laparotomy. Intrauterine contraceptive devices may migrate into the peritoneal cavity and produce peritonitis and intestinal obstruction.