Abdominal Pain (cont.)

Abdominal pain is caused by inflammation (for example, appendicitis, diverticulitis, colitis), by stretching or distention of an organ (for example, 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 (for example, 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 the 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 (for example, spasm) or abnormally sensitive nerves within the intestines that give rise to painful sensations inappropriately (visceral hyper-sensitivity). These latter types of pain are often referred to as functional pain because no recognizable (visible) causes for the pain have been found - at least not yet.

Doctors determine the cause of abdominal pain by relying on:

1. characteristics of the pain,
2. findings on physical examination,
3. laboratory, radiological, and endoscopic testing, and
4. surgery.

The following information, obtained by taking a patient's history, is important in helping doctors determine the cause of pain:

• The way the pain begins. For example, abdominal pain that comes on suddenly suggests a sudden event, for example, the interruption of the supply of blood to the colon (ischemia) or obstruction of the bile duct by a gallstone (biliary colic).
• The location of the pain.
  • Appendicitis typically causes pain in the middle of the abdomen, and then moves the right lower abdomen, the usual location of the appendix.
  • Diverticulitis typically causes pain in the left lower abdomen where most colonic diverticuli are located.
  • Pain from the gallbladder (biliary colic or cholecystitis) typically is felt in the middle, upper abdomen or the right upper abdomen near where the gallbladder is located.
• The pattern of the pain.
  • Obstruction of the intestine initially causes waves of crampy abdominal pain due to contractions of the intestinal muscles and distention of the intestine.
  • True cramp-like pain suggests vigorous contractions of the intestines.
  • Obstruction of the bile ducts by gallstones typically causes steady (constant) upper abdominal pain that lasts between 30 minutes and several hours.
  • Acute pancreatitis typically causes severe, unrelenting, steady pain in the upper abdomen and upper back. The pain of acute appendicitis initially may start near the umbilicus, but as the inflammation progresses, the pain moves to the right lower abdomen. The character of pain may change over time. For example, obstruction of the bile ducts sometimes progresses to inflammation of the gallbladder with or without infection (acute cholecystitis). When this happens, the characteristics of the pain change to those of inflammatory pain. (See below.)
• The duration of the pain.
  • The pain of IBS typically waxes and wanes over months or years and may last for years or decades.
  • Biliary colic lasts no more than several hours.
  • The pain of pancreatitis lasts one or more days.
  • The pain of acid-related diseases - gastroesophageal reflux disease (GERD) or duodenal ulcers - typically show periodicity, that is, a period of weeks or months during which the pain is worse followed by periods of weeks or months during which the pain is better.
  • Functional pain may show this same pattern of periodicity.
• What makes the pain worse. Pain due to inflammation (appendicitis, diverticulitis, cholecystitis, pancreatitis) typically is aggravated by sneezing, coughing or any jarring motion. Patients with inflammation as the cause of their pain prefer to lie still.
• What relieves the pain.
  • The pain of IBS and constipation often is relieved temporarily by bowel movements and may be  associated with changes in bowel habit.
  • Pain due to obstruction of the stomach or upper small intestine may be relieved temporarily by vomiting which reduces the distention that is caused by the obstruction.
  • Eating or taking antacids may temporarily relieve the pain of ulcers of the stomach or duodenum because both food and antacids neutralize (counter) the acid that is responsible for irritating the ulcers and causing the pain.
  • Pain that awakens patients from sleep is more likely to be due to non-functional causes.

Source: MedicineNet.com
http://www.medicinenet.com/abdominal_pain/article.htm