Toxic megacolon is a rare, potentially life-threatening condition that occurs when inflammation spreads into the deeper layers of the colon causing the colon to widen, and in severe cases, rupture.
- If the colon ruptures, a person is at risk for infection throughout the body, shock, and dehydration.
- If the colon does not perforate or rupture and the condition is treated promptly, the survival rate for toxic megacolon is nearly 98%. Even in cases where the colon ruptures, the survival rate still approaches 80%.
What Are Symptoms of Toxic Megacolon?
Symptoms of toxic megacolon result from the rapid widening of the colon, occur over a short period of time, and may include:
- Distended abdomen
- Pain in the abdomen
- Fever (sepsis, which is widespread infection in the body)
- Diarrhea (usually bloody)
- Rapid heart rate
- Shock
Get to a hospital’s emergency department or call 911 if you develop severe abdominal pain along with:
- Bloody diarrhea
- Frequent diarrhea
- Fever
- Rapid heart rate
- Tenderness when the abdomen is pressed
- Abdominal distention
What Causes Toxic Megacolon?
Toxic megacolon may occur in people who have colon inflammation due to:
- Inflammatory bowel diseases (IBD) such as ulcerative colitis or Crohn’s disease that are not well controlled
- Clostridioides difficile (C. diff) infection of the colon
- Ischemic bowel disease (reduced blood flow to the colon)
- Colon cancer
Risk factors for developing toxic megacolon include:
- Diabetes
- Organ transplantation
- Kidney failure
- Immunosuppression
- Chronic obstructive pulmonary disease (COPD)
How Is Toxic Megacolon Diagnosed?
Toxic megacolon is diagnosed with a patient history and physical examination of the abdomen, along with tests such as:
- Imaging tests of the abdomen
- X-ray
- Ultrasound
- Computerized tomography (CT) scan
- Magnetic resonance imaging (MRI) scan
- Blood tests
- Blood electrolytes
- Complete blood count (CBC)
What Is the Treatment for Toxic Megacolon?
Treatment of toxic megacolon usually involves treating the underlying condition that led to toxic megacolon, and may include:
- Steroids
- Immunosuppressants
- Anti-inflammatory medications
- Antibiotics
- Bowel rest and bowel decompression to remove gas and substances filling the colon
If patients develop septic shock, they will be If admitted to a hospital’s intensive care unit (ICU), where treatment may include:
- Mechanical ventilation
- Dialysis for kidney failure
- Medications to treat low blood pressure, infection, or poor blood clotting
- Intravenous (IV) fluids
- Oxygen
What Are Complications of Toxic Megacolon?
Complications of toxic megacolon may include:
- Bleeding and blood loss
- Perforation of the colon
- Whole-body infection (sepsis)
- Shock
- Death
From 
https://www.mountsinai.org/health-library/diseases-conditions/toxic-megacolon
https://www.hopkinsmedicine.org/health/conditions-and-diseases/toxic-megacolon
https://www.uptodate.com/contents/toxic-megacolon#H16