From the Guidelines
Toxic megacolon is a life-threatening complication that requires immediate medical attention, and treatment should involve aggressive medical management and early surgical intervention if necessary, as indicated by the most recent guidelines 1.
Key Characteristics and Treatment
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 1. Treatment involves hospitalization with intensive care monitoring, intravenous fluids, bowel rest (nothing by mouth), and broad-spectrum antibiotics such as piperacillin-tazobactam 4.5g IV every 6 hours plus metronidazole 500mg IV every 8 hours. Nasogastric tube decompression is often necessary, and corticosteroids like hydrocortisone 100mg IV every 8 hours may be used for inflammatory bowel disease-related cases.
Indications for Surgery
Patients should be closely monitored for signs of perforation or worsening sepsis, and if medical management fails or perforation occurs, emergency colectomy is required 1. The condition typically results from severe inflammatory bowel disease (ulcerative colitis or Crohn's disease), Clostridioides difficile infection, or other severe colonic infections. Surgery is mandatory in patients presenting with toxic megacolon complicated by perforation, massive bleeding, clinical deterioration, and signs of shock 1.
Pathophysiology and Mortality
The pathophysiology involves transmural inflammation leading to neuromuscular dysfunction, colonic dilation exceeding 6cm, and potential perforation. Early recognition and aggressive management are crucial as mortality rates can reach 30% if perforation occurs 1. Persistent fever after 48–72 h of steroid therapy should raise the possibility of local perforation or abscess, and free perforation, massive hemorrhage, increasing transfusion requirements, increasing signs of toxicity, and progression of colonic dilatation are indications for an urgent operation 1.
From the Research
Definition and Characteristics of Toxic Megacolon
- Toxic megacolon (TM) is a fatal complication of inflammatory bowel disease (IBD) or any infectious etiology of the colon, characterized by total or partial nonobstructive colonic dilatation and systemic toxicity 2.
- It is associated with high morbidity and mortality, and surgical management is necessary for the majority of cases 2, 3.
- The main characteristics of toxic megacolon are toxemia, sepsis, and distension of the colon due to diminished muscular tone, loss of motor activity, and increased amount of colonic gas 4.
Diagnosis of Toxic Megacolon
- An accurate history and physical examination, plain radiographs of the abdomen, sigmoidoscopy, and awareness of the condition facilitate diagnosis in most cases 2.
- The most important diagnostic procedure is the abdominal X-ray, and a diameter of colonic distension exceeding 60 mm confirms the diagnosis of toxic megacolon 4.
- Computed tomography scanning and transabdominal intestinal ultrasound are promising alternatives that add additional information 5.
Management of Toxic Megacolon
- Management involves close medical attention, supportive care, and treatment of the underlying colitis 3.
- Possible exacerbating factors such as narcotic and anticholinergic medications must be withdrawn, and colonic decompression via tube drainage or positional techniques must be considered 3.
- Conservative treatment consists of water and electrolyte replacement, total parenteral nutrition, administration of corticosteroids and broad-spectrum antibiotics, and repeat patient's prone positioning 4.
- If medical therapy is not successful during the first 72 hours, surgical intervention is indicated, and the most common procedure is subtotal colonic resection with creation of an ileostomy 4, 5.