Acute Abdomen

An acute abdomen is a condition that demands urgent attention & treatment

• Physiology of Abdominal Pain

  • Visceral Pain (i.e., plural of viscus, an organ inside of the body)

    • midline, poorly localized, deep, dull, & corresponds to embryonic anatomic origin

    • due to contraction, spasm, stretching, distention, chemical irritation, inflammation

    • Foregut (stomach to ligament of Treitz)

      • incl. distal esophagus, stomach, duodenum, pancreas, gallbladder, liver

      • transmitted via celiac plexus

      • experienced in epigastrium

    • Midgut (ligament of Treitz to distal transverse colon)

      • incl. jejunum, ileum, appendix, cecum, ascending colon, proximal transverse colon

      • transmitted via celiac plexus

      • experienced in periumbilicus

    • Hindgut (distal transverse colon to proximal rectum)

      • incl. distal transverse colon, descending colon, sigmoid colon, proximal rectum

      • transmitted via inferior epigastric plexus

      • experienced in suprapubic

  • Somatic Pain

    • sharper & better localized

    • due to direct parietal peritoneal irritation (i.e., peritonitis)

    • transmitted by segmental somatic nerve fibers

    • anterior abdominal wall involvement causes reflexive muscle contraction (i.e., rigidity, guarding)

    • pelvis & posterior abdominal wall can have indirect signs (i.e., psoas sign, ureteral colic)

  • Referred Pain

    • no consensus on the mechanism, but the convergent-projection theory proposes that afferent visceral sensory fibers entering the same spinal dorsal root ganglia as somatic fibers are misinterpreted as pain arising from somewhere on the body wall as opposed to the viscera

    • cholecystitis can refer to the right shoulder

    • pleuritic pain can refer to the ipsilateral flank