Treatment of Enterocolitis
Determine the Type of Enterocolitis First
The treatment approach depends critically on identifying which type of enterocolitis you're managing, as therapeutic strategies differ fundamentally between immune checkpoint inhibitor (ICI) enterocolitis, neutropenic enterocolitis, and inflammatory bowel disease-related colitis.
Immune Checkpoint Inhibitor (ICI) Enterocolitis
Initial Diagnostic Steps
Before starting immunosuppression, rule out infectious causes through stool testing for C. difficile, bacterial cultures, and parasites. 1 Perform flexible sigmoidoscopy with biopsies, as approximately 95% of ICI enterocolitis cases show left colon inflammation, making this approach adequate for diagnosis. 2 Reserve CT imaging only for patients with pain, fever, or bleeding—diarrhea alone does not warrant abdominal imaging. 1
First-Line Treatment: Systemic Glucocorticoids
Initiate systemic glucocorticoids at 0.5–2 mg/kg prednisone equivalent daily (oral or IV) as first-line therapy, with a 4–6 week taper. 2, 1 For mild cases (grade 1-2), consider mesalamine or oral corticosteroids, while moderate to severe cases require withholding ICI therapy and administering IV corticosteroids. 1
Second-Line Immunosuppression Criteria
Escalate to second-line therapy if patients fail to respond within 72 hours of high-dose glucocorticoids or lack complete response within one week. 2 Approximately one-third of patients require second-line agents. 1 The presence of colonic ulceration on endoscopy is the only validated predictor for needing secondary immunosuppression—CTCAE grading is not predictive. 2, 1
Biologic Agent Selection
Use infliximab 5 mg/kg IV or vedolizumab 300 mg IV at weeks 0,2, and 6 as second-line agents. 1, 3 Choose vedolizumab over infliximab in patients with concurrent ICI hepatitis, as infliximab can rarely induce hepatitis. 1 Both agents are FDA-approved for ulcerative colitis and have demonstrated efficacy in steroid-refractory cases. 3
Critical Pitfall to Avoid
Do not rely on CTCAE grading to predict treatment escalation needs—only endoscopic evidence of colonic ulceration reliably identifies patients who will require second-line immunosuppression. 1
Neutropenic Enterocolitis
Immediate Management Bundle
Start broad-spectrum antibiotics immediately upon diagnosis, along with granulocyte colony-stimulating factors (G-CSFs), nasogastric decompression, IV fluids, and bowel rest. 1, 4 This condition occurs when absolute neutrophil count falls below 500 cells/mL, typically 2 days after neutropenia onset. 5
Antibiotic Regimen Selection
Use monotherapy with piperacillin-tazobactam or imipenem-cilastatin, OR combination therapy with cefepime or ceftazidime plus metronidazole to cover enteric gram-negatives, gram-positives, and anaerobes. 1, 4 Add antifungal therapy if no response to antibacterial agents occurs, as fungemia is common. 4
Diagnostic Imaging
Obtain CT scanning as the preferred modality, which shows concentric bowel wall thickening, pericolic fluid collections, or pneumatosis intestinalis. 1, 4 Delayed imaging increases complication risk (OR 1.10 per day delay). 5
Surgical Intervention Indications
Proceed to surgery for persistent GI bleeding after correcting thrombocytopenia/coagulopathy, free intraperitoneal perforation, abscess formation, or clinical deterioration despite aggressive medical management. 1, 4 Perform right hemicolectomy with resection of all necrotic tissue; avoid primary anastomosis in severely immunocompromised patients due to high anastomotic leak risk. 4
Medications to Avoid
Do not use anticholinergic agents, antidiarrheals, or opioids, as they aggravate ileus. 4
Inflammatory Bowel Disease-Related Enterocolitis
First-Line Approach for Diffuse Descending Colon Disease
Initiate mesalamine 2-4 g daily orally combined with mesalamine 1 g daily topically (rectal) for diffuse enterocolitis in the descending colon. 6 This combination approach is superior to monotherapy for inducing mucosal healing. 7, 8 Monitor clinical response every 3-7 days by evaluating stool frequency and consistency. 6
Corticosteroid Escalation
If inadequate response after 7-14 days of mesalamine, start prednisone 40 mg daily orally with gradual taper over 8 weeks. 6 Glucocorticoids are highly effective for acute treatment but should only be used short-term due to significant side effects. 7
Refractory Disease Management
For cases refractory to corticosteroids for more than 3 days, escalate to biologic therapy with infliximab or vedolizumab. 6 Consider budesonide for microscopic colitis if endoscopic findings are compatible. 6
Maintenance Strategy
Maintain long-term aminosalicylate therapy to prevent relapses once remission is achieved. 6 Mucosal healing reduces recurrence, colorectal cancer risk, need for surgery, and improves quality of life. 8
Neonatal Necrotizing Enterocolitis (NEC)
Institute bowel rest, IV fluid administration, total parenteral nutrition, and broad-spectrum antibiotics immediately. 1 Perform peritoneal drainage or surgical bowel resection with stoma creation when indicated. 1 Mortality approaches 95% when the entire bowel is involved, which occurs in approximately 25% of cases. 1, 9