Acute colonic pseudoobstruction.

Acute colonic pseudoobstruction (ACPO) is a clinical condition of acute large bowel obstruction without mechanical blockage. ACPO occurs most often in hospitalized patients with serious underlying medical and surgical conditions. ACPO is an important cause of morbidity and mortality. The pathogenesis of ACPO is not completely understood but likely results from an imbalance in the autonomic regulation of colonic motor function. Metabolic or pharmacologic factors, as well as spinal or retroperitoneal trauma, may alter the autonomic regulation of colonic function, leading to excessive parasympathetic suppression or sympathetic stimulation. This imbalance results in colonic atony and pseudoobstruction. Early recognition and appropriate management are critical to minimizing morbidity and mortality. The mortality rate is estimated at 40% when ischemia or perforation occurs. The best documented treatment of ACPO is intravenous neostigmine, which leads to prompt decompression in the majority of patients after a single infusion. In patients failing or having contraindications to neostigmine, colonoscopic decompression is the active intervention of choice. Surgery is reserved for those with overt peritonitis or perforation.