What is the treatment for enterocolitis?

Treatment of Enterocolitis

The treatment of enterocolitis depends critically on the underlying etiology, with immune checkpoint inhibitor (ICI)-induced enterocolitis requiring systemic corticosteroids as first-line therapy, neutropenic enterocolitis demanding immediate broad-spectrum antibiotics with supportive care, and severe ulcerative colitis necessitating intravenous corticosteroids with early consideration of rescue therapy. 1, 2, 3

Immune Checkpoint Inhibitor (ICI)-Induced Enterocolitis

Mild Disease (Grade 1-2)

• Initiate oral corticosteroids or mesalamine for symptomatic patients, while continuing to monitor closely. 1
• Anti-diarrheal agents and fluid/electrolyte supplementation can be used for non-severe diarrhea. 3
• ICI therapy may be continued if symptoms remain mild without alarm features. 3

Moderate to Severe Disease (Grade 3-4)

• Immediately discontinue ICI therapy and administer intravenous corticosteroids at 1-2 mg/kg per day (prednisone equivalent). 3, 1
• The American Gastroenterological Association recommends dosing at 0.5-2 mg/kg daily with a 4-6 week taper. 1
• Perform flexible sigmoidoscopy or colonoscopy with biopsies to confirm diagnosis and assess for colonic ulceration, which predicts need for second-line therapy. 3, 1
• Obtain stool cultures for enteropathogens, C. difficile toxin, and consider CMV testing before escalating immunosuppression. 3, 1

Steroid-Refractory Disease

• If no improvement within 3-5 days of IV corticosteroids, escalate to infliximab (5 mg/kg IV) or vedolizumab (300 mg IV). 3, 1
• Approximately one-third of patients fail first-line glucocorticoid treatment and require second-line immunosuppression. 1
• A single dose of infliximab is generally sufficient, though some patients require a second dose at 2 weeks. 3
• Choose vedolizumab over infliximab in patients with concurrent ICI hepatitis, as infliximab can induce rare hepatitis. 1
• Both agents are given at weeks 0,2, and 6 for maintenance therapy. 1

Critical Pitfall

• Do not rely on CTCAE grading alone to predict need for second-line immunosuppression; only colonic ulceration on endoscopy is predictive. 1
• Do not delay imaging in patients with pain, fever, or bleeding, though diarrhea alone does not warrant abdominal imaging. 1

Neutropenic Enterocolitis

Initial Medical Management

• Immediately initiate broad-spectrum antibiotics covering enteric gram-negative organisms, gram-positive organisms, and anaerobes. 1, 2
• Recommended regimens include monotherapy with piperacillin-tazobactam or imipenem-cilastatin, or combination therapy with cefepime/ceftazidime plus metronidazole. 1, 2
• Administer granulocyte colony-stimulating factors (G-CSFs) to accelerate neutrophil recovery. 1, 2
• Implement bowel rest with nasogastric decompression and provide aggressive intravenous fluid resuscitation. 1, 2
• Add antifungal therapy if no response to antibacterial agents, as fungemia is common. 2

Diagnostic Workup

• Obtain CT scanning as the preferred imaging modality, looking for bowel wall thickening >4 mm, pericolic fluid collections, or pneumatosis intestinalis. 2
• Abdominal ultrasonography showing bowel wall thickness >10 mm is associated with 60% mortality versus 4.2% for ≤10 mm. 2
• Standardized diagnostic criteria require neutropenia (ANC <500 cells/mL), bowel wall thickening >4 mm, and exclusion of C. difficile. 2

Surgical Intervention

• Operate emergently for free intraperitoneal perforation, abscess formation, persistent GI bleeding after correction of coagulopathy, or clinical deterioration despite aggressive medical management. 1, 2
• Resect all necrotic material, usually by right hemicolectomy. 2
• Avoid primary anastomosis in severely immunocompromised patients due to increased risk of anastomotic leak; create stomas instead. 1, 2

Critical Caveats

• Avoid anticholinergic, antidiarrheal, and opioid agents as they may aggravate ileus. 2
• Mortality rates range from 30-82% if treatment is delayed, making early recognition critical. 2

Severe Ulcerative Colitis

Initial Therapy

• Administer intravenous corticosteroids using methylprednisolone 60 mg every 24 hours or hydrocortisone 100 mg four times daily. 3
• Higher doses are no more effective, but lower doses are less effective. 3
• Provide IV fluid and electrolyte replacement with at least 60 mmol/day potassium supplementation, as hypokalemia can promote toxic dilatation. 3
• Administer subcutaneous prophylactic low-molecular-weight heparin for thromboprophylaxis. 3

Diagnostic Evaluation

• Perform unprepared flexible sigmoidoscopy with biopsies to confirm diagnosis and exclude CMV infection. 3
• Obtain stool cultures and C. difficile toxin assay; if C. difficile is detected, administer oral vancomycin and consider fecal microbial transplant. 3

Rescue Therapy

• Consider second-line medical therapy with infliximab, ciclosporin (2 mg/kg/day IV), or tacrolimus on or around Day 3 of steroid therapy if inadequate response. 3
• Treatment beyond 7-10 days carries no additional benefit and increases morbidity. 3
• Ciclosporin 2 mg/kg/day IV monotherapy is useful for patients who should avoid steroids (steroid psychosis, osteoporosis, poorly controlled diabetes). 3

Surgical Considerations

• Ensure joint care by gastroenterologist and colorectal surgeon, as delayed surgery in patients on ineffective medical therapy results in high morbidity. 3
• Identify early those likely to require colectomy while not delaying rescue medical therapy. 3

Supportive Care

• Provide enteral nutrition if malnourished, as it has fewer complications than parenteral nutrition (9% vs 35%). 3
• Withdraw anticholinergic, anti-diarrheal, non-steroidal anti-inflammatory, and opioid drugs. 3

Bacterial Enterocolitis

• Most bacterial colitis infections (Campylobacter, Salmonella, Shigella, E. coli, Yersinia) are self-limiting. 4
• Reserve antibiotics for high-risk patients and those with complicated disease. 4
• Definitive diagnosis requires bacterial identification through stool culture, rectal swab culture, or detection of specific bacterial toxins. 4