Ogilvie Syndrome

Ogilvie syndrome, or acute colonic pseudo-obstruction (ACPO), is a clinical disorder with the signs, symptoms, and radiographic appearance of an acute large bowel obstruction with no evidence of distal colonic obstruction. The colon may become massively dilated; if not decompressed, the patient risks perforation, peritonitis, and death.

In 1948, Sir Heneage Ogilvie described 2 patients with metastatic cancer and retroperitoneal spread to the celiac plexus. The patients also had signs and symptoms of colonic obstruction but with no evidence of organic obstruction to the intestinal flow. Ogilvie hypothesized that the etiology of their conditions was an imbalance in the autonomic nervous system with sympathetic deprivation to the colon leading to unopposed parasympathetic tone, regional contraction, and, thus, a functional obstruction.

In 1958, Dudley et al used the term pseudo-obstruction to describe the clinical appearance of a mechanical obstruction with no evidence of organic disease during laparotomy.

PATOFISIOLOGI

The pathophysiology of ACPO is not clearly understood. Research into the neurophysiology of the colon reveals that Ogilvie's hypothesis was close to the proposed current understanding. The parasympathetic nervous system is responsible for stimulating gut motility. The vagus nerve supplies the parasympathetic tone from the upper GI tract to the splenic flexure, and the sacral parasympathetic nerves (S2 to S5) supply the left colon and rectum. Sympathetic stimuli result in the inhibition of bowel motility and contraction of sphincters. The lower 6 thoracic segments supply the sympathetic tone to the right colon, while lumbar segments 1-3 supply the left colon.

Based on evidence from pharmacologic studies, metabolic abnormalities, retroperitoneal trauma, and various spinal blockade studies, an imbalance in the autonomic innervation appears to lead to a functional bowel obstruction. Unlike Ogilvie's hypothesis, some current evidence suggests that an interruption of the sacral parasympathetic nerves occurs, leading to an adynamic distal colon that is similar to Hirschsprung disease, except with normal ganglion cells observable on autopsy. Other research supports the belief that the sympathetic tone increases in these patients, who usually are very ill, leading to inhibition of colonic motility.

The cecum is the usual site of the largest dilatation in patients with ACPO and is thus prone to the greatest risk of perforation. The Laplace law indicates that the intraluminal pressure needed to stretch the wall of a hollow tube is inversely proportional to its diameter. The largest diameter in the colon is the cecum; therefore, the cecum requires the smallest amount of pressure to increase in size and to thus increase wall tension. As the wall tension of the colon increases, ischemia with longitudinal splitting of the serosa, herniation of the mucosa, and perforation can occur.