35 - Acute Colonic Pseudo-Obstruction

Abstract

Acute colonic pseudo-obstruction (ACPO) is a disorder characterized by massive dilation of the colon in the absence of mechanical obstruction. This severe motility disturbance, also known as Ogilvie’s syndrome, usually develops in hospitalized patients and is associated with various medical and surgical conditions. The tension on the colon wall resulting from extreme dilation can lead to ischemic necrosis and perforation, especially in the cecum. Approximately 75% of patients with ACPO recover over an average of 3 to 5 days when treated with conservative measures. During the recovery phase, however, ACPO causes significant discomfort and immobilization and prevents institution of enteral nutrition. The risk of major complications, mortality, and the morbidity of the long recovery led to a search for effective and safe therapies, not only to prevent ischemia and perforation, but also to speed resolution. The first step in management of ACPO is to confirm the diagnosis and rule out true obstruction, usually by CT scan. Then, conservative measures like NPO status, nasogastric suctioning, rectal tube, mobilization of patient, correction of electrolyte abnormalities, and discontinuation of anti-motility medications like narcotics have been shown to succeed in most patients. For the 25% of patients who fail to respond to conservative therapy, more active interventions are instituted. Medication therapy with neostigmine, a cholinesterase inhibitor, has been shown to be rapidly effective and safe in most patients. Colonoscopy with decompression tube placement is generally next for those failing neostigmine. Surgery is reserved for those with perforation and/or severe ischemic necrosis.