1. Lyon C, Clark DC. Diagnosis of acute abdominal pain in older patients. Am Fam Physician. 2006;74(9):1537-1544.

Visceral pain comes from the abdominal viscera, which are innervated by autonomic nerve fibers and respond mainly to the sensations of distention and muscular contraction—not to cutting, tearing, or local irritation. Visceral pain is typically vague, dull, and nauseating. It is poorly localized and tends to be referred to areas corresponding to the embryonic origin of the affected structure. Foregut structures (stomach, duodenum, liver, and pancreas) cause upper abdominal pain. Midgut structures (small bowel, proximal colon, and appendix) cause periumbilical pain. Hindgut structures (distal colon and genitourinary tract) cause lower abdominal pain.

Many intra-abdominal disorders cause abdominal pain (see figure ); some are trivial, but some are immediately life threatening, requiring rapid diagnosis and surgery. These include ruptured abdominal aortic aneurysm Аневризми черевної аорти (АЧА) $\"Аневризми$ (AAA), perforated viscus, mesenteric ischemia Гостра мезентеріальна ішемія $\"Гостра$ , and ruptured ectopic pregnancy Позаматкова вагітність . Others (eg, intestinal obstruction Кишкова непрохідність $\"Кишкова$ , appendicitis Апендицит $\"Апендицит\"$ , severe acute pancreatitis Гострий панкреатит $\"Гострий$ ) are also serious and nearly as urgent. Several extra-abdominal disorders also cause abdominal pain (see table ).

Evaluation of mild and severe pain follows the same process, although with severe abdominal pain, therapy sometimes proceeds simultaneously and involves early consultation with a surgeon. History and physical examination usually exclude all but a few possible causes, with final diagnosis confirmed by judicious use of laboratory and imaging tests. Life-threatening causes should always be ruled out before focusing on less serious diagnoses.

Some clinicians feel that providing pain relief before a diagnosis is made interferes with their ability to evaluate. However, moderate doses of IV analgesics (eg, fentanyl 50 to 100 mcg, morphine 4 to 6 mg) do not mask peritoneal signs and, by diminishing anxiety and discomfort, often make examination easier ( 1 ).

Look for life-threatening causes first.