From the Guidelines
A patient with an acute flare of ulcerative colitis is at greatest risk for toxic megacolon, a life-threatening complication that requires immediate medical attention. This condition occurs when severe inflammation causes the colon to dilate abnormally, leading to decreased motility and potential perforation. According to the most recent and highest quality study 1, toxic megacolon is characterized by radiographic evidence of total or segmental colonic distention of > 6 cm, presence of systemic toxicity, and inflammatory or infectious etiology.
The management of toxic megacolon requires a multidisciplinary approach, including:
- Immediate hospitalization
- Bowel rest (NPO status)
- IV fluids
- Broad-spectrum antibiotics (typically a combination of metronidazole 500mg IV q8h plus a third-generation cephalosporin or fluoroquinolone)
- IV corticosteroids (methylprednisolone 40-60mg daily)
- Surgical consultation, as emergency colectomy may be necessary if medical management fails
The pathophysiology of toxic megacolon involves severe transmural inflammation leading to destruction of the myenteric plexus and subsequent colonic dilation, which can rapidly progress to perforation and sepsis if not promptly addressed 1. While venous thromboembolism and bowel perforation are also potential complications of severe ulcerative colitis, toxic megacolon represents the most immediate and severe risk during an acute flare.
Key risk factors for toxic megacolon include:
- Hypokalaemia
- Hypomagnesaemia
- Bowel preparation
- Use of anti-diarrhoeal therapy
- Earlier diagnosis of severe colitis, more intensive medical management, and earlier surgery have reduced the incidence and mortality of toxic megacolon complicating UC 1.
It is essential to identify patients at risk for toxic megacolon early and to decide when to start rescue medical therapy, as delayed surgery is associated with high morbidity 1.
From the Research
Risks Associated with Acute Flare of Ulcerative Colitis
- A patient with an acute flare of ulcerative colitis is at greatest risk for:
- Toxic megacolon: a clinical condition associated with high risk of colonic perforation, which significantly increases mortality when causing diffuse peritonitis 2
- Bowel perforation: a serious complication that can occur in patients with acute severe ulcerative colitis, especially if left untreated or if treatment is delayed 3, 2, 4
- Venous thromboembolism: patients with acute severe ulcerative colitis are at high risk for thromboembolic complications, and DVT prophylaxis should be started as soon as possible 5
- Pericarditis: not directly mentioned as a common complication of acute flare of ulcerative colitis in the provided studies
Comparison of Risks
- While all the options are potential complications of ulcerative colitis, toxic megacolon and bowel perforation are more directly related to the acute flare of the disease 6, 3, 2, 4
- Venous thromboembolism is a significant risk, but it is more of a general complication of hospitalized patients with acute colitis, rather than a direct result of the acute flare 5
- Pericarditis is not mentioned as a common complication of acute flare of ulcerative colitis in the provided studies, making it less likely to be the correct answer