Acute Megacolon Treatment & Management
- Author: Roberto M Gamarra, MD; Chief Editor: BS Anand, MD more...
Conservative management is preferred when the patient is clinically stable. Consider the following:
The underlying cause is treated, if possible, such as correction of any electrolyte/metabolic abnormalities and removal of medications that may decrease colonic motility (eg, narcotics, anticholinergic agents, calcium channel antagonists).
Oral feeding should be discontinued, and intravenous fluids should be initiated.
If nausea and vomiting are present, nasogastric decompression should be initiated.
Use of a rectal tube
Decompression using a rectal tube may assist in the treatment only if the sigmoid colon is involved. When such tubes are used, anecdotal experience has demonstrated that frequent position changes for the patient may help improve decompression. Complications with these rectal tubes include tube obstruction and colonic/rectal ulceration.
If the dilatation persists or worsens, colonoscopic decompression with or without placement of a tube in the right colon should be considered. Although the placement of a decompression tube per rectum is generally suggested, some experts believe that the tube often becomes obstructed with stool and ceases to work after a short time. Randomized controlled trials of the efficacy of colonoscopic decompression are lacking. The resolution of ileus, perforation, and mortality rates are similar between endoscopic and conservative management.
Neostigmine (adrenergic antagonist) has been demonstrated in noncontrolled and controlled studies to improve acute colonic megacolon. Whether a trial of neostigmine should be performed before or after colonoscopic decompression is unclear.
The major indication for its use is failure of conservative therapy after 72 hours. Failure of conservative therapy is generally defined by a cecal diameter of greater than 9 cm.
Contraindications include bradycardia, systolic blood pressure of less than 90 mm Hg, active bronchospasm, serum creatinine level of greater than 3 mg/dL, and evidence of bowel perforation.
Adverse events include abdominal cramping (17%), excessive salivation (13%), transient bradycardia (6%), diaphoresis (4%), and nausea and vomiting (4%). Based on expert opinion, a starting dose of 1 mg may reduce the likelihood of bradycardia.
Cardiac monitoring of patients during treatment with neostigmine is generally recommended, and atropine should be at the bedside.
A second dose of neostigmine should be considered if there is a partial or minimal response to the initial administration.
Of note, although neostigmine often induces clinical decompression, this decompression has not been shown to reduce perforation and mortality rates.
The urgency of management often depends on the size of the colon and the rate of change of the cecal diameter. Some experts believe that regardless of the criteria used for defining acute megacolon, the diameter of the cecum is the most important criterion because the cecum is generally the area that perforates. While the diameter at which the cecum perforates is variable, expert experience indicates that the cecum rarely perforates at a diameter of less than 12 cm.
Once relieved, close follow-up care, including physical examination and maintenance of a normal electrolyte balance, is important.
Avoid using agents that slow transit time, such as opiates and anticholinergics.
Diet and activity
Most patients are in the hospital when acute pseudo-obstruction is diagnosed, and bowel rest should be instituted. Parenteral nutrition may be considered depending on the patient's nutritional status.
Because many of the cases of acute pseudo-obstruction occur postoperatively, patients tend to be at bed rest. Remembering to continue prophylaxis for deep venous thrombosis, per the individual physician's protocol, is important; however, if the patient is not severely ill, is not in severe pain, and is stable to ambulate, no reason exists for the patient to remain in bed.
In view of the high rate of recurrence of colonic dilation following medical and endoscopic therapies, other therapeutic modalities have been proposed.
Percutaneous cecostomy may successfully allow for colonic decompression, but complications with this procedure are high.
Surgical options include cecostomy, colostomy, or colectomy, although surgical therapies are associated with even poorer outcomes. A colectomy is indicated if perforation or colonic ischemia is present.
Frasko R, Uchytil Z, Svab J, Vyborny J, Krska Z. [Treatment outcomes in patients with toxic megacolon]. Rozhl Chir. 2011 Jun. 90(6):339-42. [Medline].
Vanek VW, Al-Salti M. Acute pseudo-obstruction of the colon (Ogilvie's syndrome). An analysis of 400 cases. Dis Colon Rectum. 1986 Mar. 29(3):203-10. [Medline].
Tan CB, Rajan D, Shah M, Ahmed S, Freedman L, Rizvon K, et al. Toxic megacolon from fulminant Clostridium difficile infection induced by topical silver sulphadiazine. BMJ Case Rep. 2012 Aug 8. 2012:[Medline].
Moulin V, Dellon P, Laurent O, Aubry S, Lubrano J, Delabrousse E. Toxic megacolon in patients with severe acute colitis: computed tomographic features. Clin Imaging. 2011 Nov. 35(6):431-6. [Medline].
Antonopoulos P, Almyroudi M, Kolonia V, Kouris S, Troumpoukis N, Economou N. Toxic Megacolon and Acute Ischemia of the Colon due to Sigmoid Stenosis Related to Diverticulitis. Case Rep Gastroenterol. 2013 Sep 11. 7(3):409-13. [Medline]. [Full Text].
Camilleri M. Acute and chronic pseudo-obstruction. Felman M, Friedman LS, Sleisenger MH. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 8th ed. Philadelphia, PA: Saunders Publishing; 2007. 2679-2702.
Fazel A, Verne GN. New solutions to an old problem: acute colonic pseudo-obstruction. J Clin Gastroenterol. 2005 Jan. 39(1):17-20. [Medline].
Geller A, Petersen BT, Gostout CJ. Endoscopic decompression for acute colonic pseudo-obstruction. Gastrointest Endosc. 1996 Aug. 44(2):144-50. [Medline].
Ponec RJ, Saunders MD, Kimmey MB. Neostigmine for the treatment of acute colonic pseudo-obstruction. N Engl J Med. 1999 Jul 15. 341(3):137-41. [Medline].
Saunders MD, Kimmey MB. Colonic pseudo-obstruction: the dilated colon in the ICU. Semin Gastrointest Dis. 2003 Jan. 14(1):20-7. [Medline].
Stephenson BM, Morgan AR, Salaman JR, Wheeler MH. Ogilvie's syndrome: a new approach to an old problem. Dis Colon Rectum. 1995 Apr. 38(4):424-7. [Medline].
Turegano-Fuentes F, Munoz-Jimenez F, Del Valle-Hernandez E, et al. Early resolution of Ogilvie's syndrome with intravenous neostigmine: a simple, effective treatment. Dis Colon Rectum. 1997 Nov. 40(11):1353-7. [Medline].