A 44-year-old previously healthy woman comes to the office due to 2 months of low-grade fever, abdominal pain, and intermittent bloody diarrhea. Her pain has dramatically increased over the past 48 hours. The patient takes no medications and has no allergies. She has lost 4.5 kg (10 lb) over the past 8 weeks. She has no recent travel history. Temperature is 38.9 C (102 F), blood pressure is 102/70 mm Hg, pulse is 118/min, and respirations are 22/min. Examination shows pale and dry mucous membranes. Abdominal examination reveals distension and diffuse tenderness. Laboratory results are as follows:
| Hemoglobin | 9.5 g/dL |
| Leukocytes | 16,000/mm3 |
HIV test is negative. X-ray of the abdomen is shown below:
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Which of the following interventions is indicated at this time?
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This patient with 2 months of low-grade fever, abdominal pain, bloody diarrhea, and weight loss likely has undiagnosed inflammatory bowel disease (IBD) (eg, ulcerative colitis). Now, she has increased pain, leukocytosis, signs of systemic toxicity (eg, fever, tachycardia), and radiographic evidence of severe colonic dilation. This presentation is most concerning for IBD-induced toxic megacolon (TM), a medical emergency that can rapidly progress to colonic perforation.
IBD patients are at the highest risk of developing TM early in the disease, usually within 3 years of diagnosis and sometimes at initial presentation. Mucosal inflammation from IBD likely causes pathologic colonic dilation through an inflammatory mediator-induced increase in nitric oxide production (which causes smooth muscle dilation) and/or extension of the mucosal inflammation into the smooth muscle layer (which causes muscle paralysis and subsequent colonic dilation).
Intravenous corticosteroids (eg, methylprednisolone) are first-line therapy for IBD-induced TM because of their potent anti-inflammatory effect. Other management includes supportive care (eg, intravenous fluids, electrolyte repletion), bowel rest and decompression (eg, nasogastric tube), and broad-spectrum antibiotics. Nonoperative management is often successful; however, surgical intervention (eg, subtotal colectomy with end-ileostomy) may be required if symptoms fail to improve.
(Choice A) Colonoscopy (typically with biopsy) is often used in the workup of IBD to distinguish between ulcerative colitis and Crohn disease. However, colonoscopy is avoided in TM because air insufflation and instrumentation within the inflamed, dilated colon carries a high risk of perforation.
(Choice B) Ganciclovir is used to treat cytomegalovirus colitis, which can progress to TM in immunocompromised patients (eg, HIV, organ transplant). However, cytomegalovirus-induced colitis is exceedingly rare in an immunocompetent patient.
(Choice D) Intravenous opioids should be avoided in patients with TM because they slow colonic motility; this can worsen colonic dilation and precipitate perforation.
Educational objective:
Patients with inflammatory bowel disease (IBD) are at highest risk of developing toxic megacolon (TM) early in the disease, sometimes at initial presentation. Patients with IBD-induced TM should receive intravenous corticosteroids.