Toxic megacolon

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Toxic megacolon occurs when swelling and inflammation spread into the deeper layers of your colon. As a result, the colon stops working and widens. In severe cases, the colon may rupture.

Alternative Names

Toxic dilation of the colon; Megarectum; Inflammatory bowel disease - toxic megacolon; Crohn disease - toxic megacolon; Ulcerative colitis - toxic megacolon


The term "toxic" means that this problem is very dangerous. Toxic megacolon may occur in people with an inflamed colon due to:

Other forms of megacolon include pseudo-obstruction, acute colonic ileus, or congenital colonic dilation. These conditions do not involve an infected or inflamed colon.


The rapid widening of the colon may cause the following symptoms to occur over a short period of time:

If the colon ruptures, symptoms may include

  • Rapid heart rate
  • Shock, when a bodywide infection leads to dangerously low blood pressure

Exams and Tests

A physical exam may reveal signs of

. The health care provider will notice tenderness in the abdomen and possible loss of .



Treatment of the disorder that led to toxic megacolon may be started, including:

  • Steroids and other medicines that suppress the immune system
  • Antibiotics

If you have septic shock, you will be admitted to the intensive care unit of the hospital. Treatment may include:

  • Breathing machine (mechanical ventilation)
  • Dialysis for kidney failure
  • Drugs to treat low blood pressure, infection, or poor blood clotting
  • Fluids given directly into a vein (intravenously)
  • Oxygen

If rapid widening is allowed to continue, an opening or rupture can form in the colon. Therefore, most cases of toxic megacolon will need surgery to remove a part of or the entire colon.

You may receive antibiotics to prevent sepsis (a severe infection).

Outlook (Prognosis)

If the condition does not improve, it can be life threatening. In this case, a colectomy is usually needed.

Possible Complications

Complications may include:

  • Perforation of the colon
  • Sepsis
  • Shock

When to Contact a Medical Professional

Go to the emergency room or call the local emergency number (such as 911) if you develop severe abdominal pain, especially if you also have:

  • Bloody diarrhea
  • Fever
  • Frequent diarrhea
  • Rapid heart rate
  • Tenderness when the abdomen is pressed


Treating diseases that cause toxic megacolon, such as ulcerative colitis or Crohn disease, can prevent this condition.


Lichtenstein GR. Inflammatory bowel disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 141.

Marrero F. Severe complications of inflammatory bowel disease. Med Clin North Am. 2008;92:671-686. PMID: 18387381

Peterson MA. Disorders of the large intestine. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 95.

Version Info

  • Last reviewed on 10/27/2015
  • Subodh K. Lal, MD, gastroenterologist with Gastrointestinal Specialists of Georgia, Austell, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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