gastrointestinal disorders
Acute Abdominal Pain
Pathophysiology of Acute Abdominal Pain
Visceral paincomes 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. Somatic paincomes from the parietal peritoneum, which is innervated by somatic nerves, which respond to irritation from infectious, chemical, or other inflammatory processes. Somatic pain is sharp and well localized. Referred painis pain perceived distant from its source and results from convergence of nerve fibers at the spinal cord. Common examples of referred pain are scapular pain due to biliary colic, groin pain due to renal colic, and shoulder pain due to blood or infection irritating the diaphragm. Peritonitis is inflammation of the peritoneal cavity. The most serious cause is Acute Perforation of the Gastrointestinal Tract , which causes immediate chemical inflammation followed shortly by infection from intestinal organisms. Peritonitis can also result from any abdominal condition that causes marked inflammation (eg, Intraperitoneal blood from any source (eg, ruptured aneurysm, trauma, surgery, Ectopic Pregnancy ) is irritating and results in peritonitis. Barium causes severe peritonitis and should never be given to a patient with suspected gastrointestinal tract perforation. However, water-soluble contrast agents can be safely used. Peritoneosystemic shunts, drains, and dialysis catheters in the peritoneal cavity predispose a patient to infectious peritonitis, as does ascitic fluid. occurs, in which the peritoneal cavity is infected by bloodborne bacteria. Spontaneous bacterial peritonitis occurs primarily in patients with Cirrhosis and Peritonitis causes fluid to shift into the peritoneal cavity and bowel, leading to severe dehydration and electrolyte disturbances. Acute Hypoxemic Respiratory Failure (AHRF, ARDS) can develop rapidly. Kidney failure, liver failure, and disseminated intravascular coagulation follow. Without treatment, death occurs within days. 