Acute colonic pseudoobstruction (ACPO) characterized
by clinical 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.
Acute Colonic Pseudoobstruction Syndrome; Nontoxic Megacolon;
Adult Hirschsprung Disease.
First described in 1948 by Sir Heneage Ogilvie, a British
physician, in two patients with signs and symptoms of colonic obstruction
but no evidence of organic obstruction to intestinal flow. An imbalance in
the autonomic nervous system with sympathetic deprivation to the colon was
hypothesized. In 1958, Dudley et al. used the term pseudoobstruction to describe the clinical
appearance of a mechanical obstruction with no evidence of organic disease
during laparotomy. An acquired condition that occurs almost exclusively in
Uncommon. No reliable data exist in the United States
and internationally. Possible male predominance ratio of 1.5:1.
Acute large-bowel obstruction in the absence of an
obvious mechanical cause. Colonic dysmotility probably results, in part,
from an imbalance in the autonomic innervation of the colon. This syndrome
most commonly follows pelvic surgery, trauma, normal pregnancy, or cesarean
section, but it has also been described in association with many conditions,
including myocardial or mesenteric ischemia, most types of surgery,
intraabdominal sepsis, pneumonia, metabolic disturbances, drugs (e.g.,
antidepressants), and multiple sclerosis. Marked dilatation of the colon may
cause localized ischemia of the serosa, resulting in splitting of the
serosa, herniation of the mucosa, and ultimately bowel perforation.
Acute colonic obstruction in the absence of a mechanical
cause confirmed clinically and radiologically.
Ogilvie syndrome almost invariably occurs in
adults (males affected more than females) who are often ill as a result of
any of the conditions mentioned in Pathophysiology. Patients are frequently
hospitalized and complain of colicky abdominal pain and distension.
Constipation, nausea, and vomiting are common, and fever may be present in
patients with ischemic or perforated bowel. Examination reveals a markedly
distended abdomen that may not be as tender as anticipated until ischemia
occurs. Plain abdominal radiographs are suggestive of a distal colonic
obstruction with proximal large-bowel dilatation. Free air is noted in the
presence of perforation. The pseudoobstruction is usually self-limited (3-6
days) and is managed conservatively with nasogastric drainage, correction of
fluid and electrolyte disturbances, and removal of pharmacologic agents that
might be implicated (e.g., opioids or anticholinergic drugs). Sympathetic
blockade caused by an epidural anesthesia may be useful in the management of
this acute problem. Colonoscopic decompression is a well-accepted form of
therapy, and CT-guided needle decompression has been described. Surgical
intervention is reserved for cases in which conservative therapy has failed
or in the presence of impending or suspected bowel perforation. Surgical
intervention carries a mortality rate of up to 40%, compared with 15%
in patients managed conservatively.
Patients are frequently ill as a
result of their underlying conditions. Fluid ...