abdominal pain, acute or chronic, localized or diffuse pain in the abdominal cavity. Abdominal pain is a significant symptom because its cause may require immediate surgical or medical intervention. The most common causes of severe abdominal pain are inflammation, perforation of an intraabdominal structure, circulatory obstruction, intestinal or ureteral obstruction, intestinal cramping, or rupture of an organ located within the abdomen. Specific conditions include appendicitis, perforated peptic ulcer, strangulated hernia, superior mesenteric arterial thrombosis, diverticulitis, and small and large bowel obstruction. Differential diagnosis of the cause of acute abdominal pain requires its localization and characterization by means of light and deep palpation; auscultation; percussion; and abdominal, rectal, or pelvic examination. Direct physical examination may be supplemented by various laboratory and radiological examinations. Aspiration of peritoneal fluid (paracentesis) for bacteriological and chemical evaluation is sometimes indicated. Conditions producing acute abdominal pain that may require surgery include appendicitis, acute or severe and chronic diverticulitis, acute and chronic cholecystitis, cholelithiasis, acute pancreatitis, perforation of a peptic ulcer, intestinal obstructions, abdominal aortic aneurysms, and trauma affecting any of the abdominal organs. Gynecological causes that may require surgery include pelvic inflammatory disease, ruptured ovarian cyst, and ectopic pregnancy. Abdominal pain associated with pregnancy may be caused by the weight of the enlarged uterus; rotation, stretching, or compression of the round ligament; or squeezing or displacement of the bowel. In addition, uterine contractions associated with preterm labor may produce severe abdominal pain. Chronic abdominal pain may be functional or may result from overeating or aerophagy. When symptoms are recurrent, an organic cause is considered. Organic sources include peptic ulcer, hiatal hernia, gastritis, chronic cholecystitis and cholelithiasis, chronic pancreatitis, pancreatic carcinoma, chronic diverticulitis, intermittent low-grade intestinal obstruction, and functional indigestion. Some systemic conditions may cause abdominal pain. Examples include systemic lupus erythematosus, lead poisoning, hypercalcemia, sickle cell anemia, diabetic acidosis, porphyria, tabes dorsalis, and black widow spider poisoning.
