From the Guidelines
Toxic megacolon is a severe complication of Clostridioides difficile (C. diff) infection, characterized by non-obstructive dilatation of the colon ≥ 5.5 cm, associated with systemic toxicity, and requires immediate medical attention. The clinical presentation of toxic megacolon in C. diff infection includes systemic toxicity, such as fever, tachycardia, leukocytosis, and abdominal distension, as well as colonic dilatation, which can lead to decreased motility, increased pressure, and risk of perforation 1.
Key Features of Toxic Megacolon
- Non-obstructive dilatation of the colon ≥ 5.5 cm
- Systemic toxicity, including fever, tachycardia, leukocytosis, and abdominal distension
- Risk factors include hypokalaemia, hypomagnesaemia, bowel preparation, and the use of anti-diarrhoeal therapy
- Requires aggressive and prompt intervention to prevent mortality
Diagnosis and Management
The diagnosis of toxic megacolon is based on clinical presentation, laboratory tests, and imaging studies, such as contrast-enhanced CT scan, which can detect signs of colonic wall thickening and free fluid 1. Management involves hospitalization with intensive care monitoring, intravenous fluids, and prompt initiation of antibiotics, such as oral vancomycin and intravenous metronidazole, or fidaxomicin as an alternative option 1.
Surgical Consultation
Surgical consultation is essential, as approximately 20% of patients will require colectomy due to perforation, worsening clinical status, or failure to improve within 24-48 hours 1. The decision to perform surgery should be based on the patient's clinical condition, and early surgical intervention is recommended in cases of fulminant colitis progressing to systemic toxicity 1.
Recent Guidelines
Recent guidelines, such as the 2021 focused update guidelines on management of Clostridioides difficile infection in adults, recommend vancomycin 500 mg 4 times daily by mouth or by nasogastric tube, and intravenously administered metronidazole 500 mg every 8 hours, particularly if ileus is present 1. These guidelines also emphasize the importance of early diagnosis and treatment, as well as the need for surgical consultation in severe cases.
From the Research
Clinical Presentation of Toxic Megacolon in C. diff Infection
The clinical presentation of toxic megacolon in Clostridioides difficile (C. diff) infection is characterized by:
- Signs of systemic toxicity
- Severe colonic distension 2
- Dilatation of the colon > 6 cm in the absence of distal obstruction
- Combination with signs of systemic toxicity, including fever, tachycardia, leukocytosis, and anaemia 3
- Abdominal CT examination showing significant colon dilation, with marked thickening of the wall 4
Diagnosis and Management
Diagnosis of toxic megacolon is made by:
- Clinical evaluation for systemic toxicity
- Imaging studies depicting colonic dilatation 2
- Plain abdominal imaging, computed tomography scanning, and transabdominal intestinal ultrasound 2 Management of toxic megacolon requires:
- Close interaction of gastroenterologists and surgeons
- Balancing of electrolytes and fluid volumes
- Broad-spectrum antibiotics, including metronidazole
- Positioning of patients and probably careful intermittent decompression 3
- Surgical intervention, such as subtotal colectomy with terminal ileostomy, if non-surgical treatment fails 5, 6, 3
Risk Factors and Treatment Outcomes
Risk factors for severe evolution of C. diff infection include: