Health Library

Health Library

Toxic Megacolon

A toxic megacolon is a rare, yet life-threatening complication of severe colon disease or infection. It is diagnosed when your colon has expanded by more than five to six centimeters.

Toxic megacolon can be deadly because it puts you at risk for systemic infection, shock, and dehydration. The condition needs immediate medical attention, usually in a hospital.


These are signs and symptoms related to toxic megacolon:

  • Swelling of the abdomen, or belly

  • Pain in the abdomen

  • Fever

  • Rapid heart rate

  • Shock

  • Diarrhea

Who’s at risk

Toxic megacolon is a complication of these conditions:

  • Ulcerative colitis. This is an inflammatory bowel disease that usually affects the colon and rectum.

  • Crohn’s disease. This is an inflammatory bowel disease that can affect any part of the digestive tract.

  • Infections of the colon. These can be caused by C. difficile, a germ that can lead to symptoms ranging from diarrhea to a potentially fatal colon inflammation.

Other risk factors include diabetes, organ transplants, kidney failure, suppressed immunity, and chronic obstructive pulmonary disease.


To make a diagnosis, your doctor will do these things:

  • Take your medical history

  • Do a physical exam

  • Order blood tests, such as a complete blood count

  • Order an abdominal X-ray or a CT scan


Treatment of toxic megacolon includes:

  • Medicines. Treating the original condition or infection may help reduce toxic megacolon. Corticosteroids can help control inflammation. Antibiotics can help treat or prevent infection.

  • Bowel rest and bowel decompression. These treatments remove gas and substances filling the colon.

  • IV fluids. You may be given an IV of fluids and electrolytes to help nourish your body and prevent dehydration.

  • Surgery. If less invasive treatments don’t reduce the size of the toxic megacolon within two to three days, you may need surgery to remove part or all of the colon.

Your doctor may have you stop taking certain medications while you're being treated for toxic megacolon. Opioids, nonsteroidal anti-inflammatory drugs, medications to stop diarrhea, antidepressants, and anticholinergic medicines are among those that can make the condition worse.


If untreated, a toxic megacolon can result in severe complications, such as:

  • Bleeding and blood loss

  • Sepsis, or whole-body infection

  • Abnormal hole in the colon called a perforation

  • Shock

Toxic megacolon can be fatal if not treated.


Your best strategy for preventing toxic megacolon is to manage chronic conditions such as ulcerative colitis and Crohn’s disease

When to call the doctor

Seek immediate medical help or have someone call 911 if you have severe abdominal pain and these symptoms:

  • Frequent diarrhea

  • Bloody diarrhea

  • Swelling in your abdomen

  • Fever

  • Rapid heart rate

  • Signs of shock, such as a weak pulse, cool or clammy skin, dilated eyes, confusion, and rapid or shallow breathing

Toxic Megacolon - WellSpan Health

Author: Vann, Madeline
Online Medical Reviewer: Kidd, India, RN, BSN, MBA
Online Medical Reviewer: Sohrabi, Farrokh, MD;
Last Review Date: 2012-04-20T00:00:00
Published Date: 2013-01-01T00:00:00
Last Review Date: 2012-12-19T00:00:00
© 2015 WellSpan Health. All Rights Reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

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