Toxic megacolon is acute dilation of the colon with signs of severe systemic illness, most often from ulcerative colitis, Crohn colitis or Clostridioides difficile infection. The thin, inflamed wall can perforate, so it is a surgical emergency.
Key symptoms
- Bloody diarrhea that may suddenly decrease
- Severe abdominal pain and bloating
- Fever and feeling very unwell
- Confusion or lightheadedness
What you find on exam
- Fever and fast heart rate
- Distended, tender abdomen with reduced bowel sounds
- Low blood pressure or dehydration
- Peritoneal signs suggest perforation
Tests
- Abdominal X-ray: colon wider than 6 cm
- Blood count: high white cell count and anemia
- Electrolytes, albumin, lactate and inflammatory markers
- Stool test for C. difficile; CT for complications
Treatment basics
- IV fluids, electrolyte correction and bowel rest
- Stop opioids, anticholinergics and antidiarrheals
- IV corticosteroids for colitis, or oral vancomycin for C. difficile
- Broad-spectrum antibiotics and an early surgical consult
- Colectomy for perforation or no improvement in 48 to 72 hours
Red flags
- Signs of perforation: rigid abdomen or free air
- Septic shock or rising lactate
- Worsening dilation on repeat X-rays
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.