What is the treatment for enterocolitis?

Treatment of Enterocolitis

The treatment of enterocolitis depends critically on the underlying etiology, with immune checkpoint inhibitor (ICI) enterocolitis requiring systemic glucocorticoids as first-line therapy, neutropenic enterocolitis requiring broad-spectrum antibiotics with supportive care, and necrotizing enterocolitis in neonates requiring bowel rest with antibiotics and potential surgical intervention. 1

Immune Checkpoint Inhibitor (ICI) Enterocolitis

First-Line Treatment

• Systemic glucocorticoids are the uniformly recommended first-line therapy for ICI enterocolitis, typically dosed at 0.5–2 mg/kg prednisone equivalent daily (oral or intravenous) with a 4–6 week taper. 2
• 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
• Lower glucocorticoid doses may have clinical benefit, as evidence suggests systemic glucocorticoids may dampen antitumor responses. 2

Second-Line Immunosuppression

• Approximately one-third of patients fail first-line glucocorticoid treatment and require second-line immunosuppression. 2
• Escalate to second-line therapy if patients do not respond within 72 hours of glucocorticoid initiation, do not achieve complete response within one week, or have recurrent symptoms during steroid taper. 2, 1
• Colonic ulceration is the only identified predictive factor for needing secondary immunosuppression, making endoscopic evaluation critical for risk stratification. 2

Biologic Therapy Selection

• Both infliximab (5 mg/kg IV) and vedolizumab (300 mg IV) are highly effective second-line agents, typically given at weeks 0,2, and 6. 2
• Responses occur rapidly, generally within less than 1 week, contrasting with inflammatory bowel disease treatment. 2
• Choose between infliximab and vedolizumab based on patient-specific factors: 2
  • Avoid infliximab in hematologic malignancies (risk of rare lymphomas) and severe congestive heart failure 2
  • Consider vedolizumab in patients with concurrent ICI hepatitis, as infliximab can induce rare hepatitis 2
  • Weigh underlying malignancy, infection risk, expected treatment duration, and concurrent immune-related adverse events 2

Critical Pre-Treatment Steps

• Test for C. difficile, CMV, and other infectious etiologies before initiating immunosuppressive treatment. 1
• Early endoscopy correlates with improved outcomes and should be performed to identify colonic ulceration. 1

Neutropenic Enterocolitis

Initial Management

• The American Society of Clinical Oncology recommends broad-spectrum antibiotics, granulocyte colony-stimulating factors (G-CSFs), nasogastric decompression, intravenous fluids, and bowel rest. 1
• Antibiotic coverage must include enteric gram-negative organisms, gram-positive organisms, and anaerobes. 1
• Recommended antibiotic regimens: 1
  • Monotherapy: piperacillin-tazobactam or imipenem-cilastatin
  • Combination therapy: cefepime or ceftazidime plus metronidazole

Diagnostic Workup

• Obtain stool cultures and C. difficile testing; consider stool ova and parasite testing based on risk factors. 1
• CT scanning is the preferred imaging modality, showing concentric bowel wall thickening, pericolic fluid collections, or pneumatosis intestinalis. 1

Surgical Indications

• The American College of Surgeons recommends surgical intervention for: 1
  • Persistent gastrointestinal bleeding after correcting thrombocytopenia and coagulopathy
  • Free intraperitoneal perforation
  • Abscess formation
  • Clinical deterioration despite aggressive supportive measures
• Primary anastomosis is not generally recommended in severely immunocompromised patients due to increased anastomotic leak risk. 1

Necrotizing Enterocolitis (Neonatal)

Medical Management

• The American Academy of Pediatrics recommends bowel rest, intravenous fluid administration, total parenteral nutrition, and broad-spectrum antibiotics. 1
• Antibiotic therapy remains a cornerstone of both medical and surgical NEC treatment, though specific guidelines are lacking. 3

Surgical Intervention

• Peritoneal drainage or surgical intervention with bowel resection and creation of stomas or reanastomosis is required when medical management fails. 1
• Mortality rate approaches 95% when NEC involves the entire bowel (occurring ~25% of the time), with overall mortality of 40%-90% in these cases. 1

Long-Term Monitoring

• Infants who develop NEC benefit from close follow-up for early diagnosis of complications including neurodevelopmental delay, failure to thrive, strictures, adhesions, cholestasis, and short bowel syndrome. 4

Common Pitfalls to Avoid

• Do not delay imaging in patients with pain, fever, or bleeding, though diarrhea alone does not warrant abdominal imaging in ICI enterocolitis. 2
• Do not rely on CTCAE grading to predict need for second-line immunosuppression in ICI enterocolitis; only colonic ulceration is predictive. 2
• Avoid delaying evaluation in elderly or institutionalized patients, as they often present atypically with minimal peritoneal signs despite advanced disease. 5
• Monitor complete blood cell counts and platelet counts in elderly patients on mesalamine, as higher incidence of blood dyscrasias occurs in patients ≥65 years. 6