Treatment of Enterocolitis
Context-Specific Management Approach
The treatment of enterocolitis depends critically on the underlying etiology—neutropenic enterocolitis, immune checkpoint inhibitor (ICI)-related enterocolitis, necrotizing enterocolitis (NEC) in neonates, postoperative enterocolitis, and infectious enterocolitis each require distinct management strategies. 1, 2, 3
Neutropenic Enterocolitis
Immediate Medical Management
- Initiate broad-spectrum antibiotics immediately covering enteric gram-negative organisms, gram-positive organisms, and anaerobes. 1
- First-line antibiotic regimens include:
- Add vancomycin if MRSA or resistant enterococcal infection is suspected 2
- Add fluconazole or amphotericin B for suspected fungal infection 2
Supportive Care
- Administer granulocyte colony-stimulating factors (G-CSFs) 1
- Perform nasogastric decompression 1, 2
- Provide intravenous fluid resuscitation 1, 2
- Enforce strict bowel rest (NPO status) 1, 2
- Avoid anticholinergic, antidiarrheal, and opioid agents as they may mask clinical deterioration 2, 3
Diagnostic Workup
- Obtain CT scanning showing concentric bowel wall thickening (>4 mm), pericolic fluid collections, or pneumatosis intestinalis 1, 4
- Perform stool cultures and C. difficile testing 1
- Monitor complete blood count for thrombocytopenia and neutropenia 2
Surgical Indications
- Operate for persistent gastrointestinal bleeding after correction of thrombocytopenia and coagulopathy, free intraperitoneal perforation, abscess formation, or clinical deterioration despite aggressive medical therapy. 1, 2
- Primary anastomosis is not recommended in severely immunocompromised patients due to increased anastomotic leak risk 1
Immune Checkpoint Inhibitor (ICI) Enterocolitis
Grading-Based Treatment Algorithm
Mild Cases (Grade 1-2):
Moderate to Severe Cases (Grade 3-4):
- Withhold ICI therapy immediately 1
- Administer IV corticosteroids at 0.5–2 mg/kg prednisone equivalent daily with 4–6 week taper 1
- Lower glucocorticoid doses may preserve antitumor responses 1
Second-Line Immunosuppression
- If no improvement within 3 days of IV corticosteroids, initiate second-line biologic therapy. 1
- Test for C. difficile, CMV, and other infectious etiologies before starting immunosuppression 1
- Approximately one-third of patients require second-line therapy 1
Biologic Selection Strategy
- Both infliximab (5 mg/kg IV) and vedolizumab (300 mg IV) are highly effective, given at weeks 0,2, and 6. 1
- Choose vedolizumab in patients with concurrent ICI hepatitis, as infliximab can induce rare hepatitis 1
- Base selection on underlying malignancy, infection risk, and concurrent immune-related adverse events 1
Critical Predictive Factor
- Colonic ulceration on endoscopy is the only identified predictor for needing secondary immunosuppression—making endoscopic evaluation critical for risk stratification. 1
- Do not rely on CTCAE grading alone to predict need for second-line therapy 1
Imaging Considerations
- Obtain imaging promptly in patients with pain, fever, or bleeding 1
- Diarrhea alone does not warrant abdominal imaging 1
Necrotizing Enterocolitis (Neonates)
Initial Resuscitation and Stabilization
- Perform fluid resuscitation to address hemodynamic instability 3
- Insert nasogastric tube for bowel decompression 3
- Initiate hemodynamic monitoring with management of sepsis/septic shock 3
Antibiotic Regimens
First-line options: 3
- Ampicillin + gentamicin + metronidazole, OR
- Ampicillin + cefotaxime + metronidazole, OR
- Meropenem monotherapy
Modifications for specific pathogens: 3
- Substitute vancomycin for ampicillin if MRSA or ampicillin-resistant enterococcal infection suspected
- Add fluconazole or amphotericin B for suspected fungal infection
Surgical Indications
- Operate urgently for evidence of bowel perforation 3
- Operate for clinical deterioration despite maximal medical therapy 3
- Surgical options include laparotomy with resection of necrotic bowel and creation of ostomies or primary anastomosis 3
- Consider peritoneal drainage as temporizing measure in very low birth weight neonates 3
- Obtain intraoperative Gram stains and cultures to guide antimicrobial therapy 3
Monitoring
- Monitor for thrombocytopenia, neutropenia, and metabolic acidosis 3
Prevention Strategies
- Consider probiotics (combinations of Lactobacillus spp. and Bifidobacterium spp.) to reduce risk of severe NEC and mortality 3
- Consider lactoferrin alone or with Lactobacillus to reduce late-onset sepsis 3
- Consider antifungal prophylaxis for extremely low birth weight infants (<1000g) 3
Prognosis
- Survival rate is approximately 95% unless NEC involves entire bowel 3
- When entire bowel is involved, mortality increases to 40-90% 3
- Nonoperative management succeeds in approximately 70% of cases 3
Severe Ulcerative Colitis (Acute Severe UC)
Initial Management
- Administer IV corticosteroids as mainstay of conventional therapy: methylprednisolone 60 mg every 24 hours OR hydrocortisone 100 mg four times daily. 5
- Higher doses are no more effective; lower doses are less effective 5
- Bolus injection is as effective as continuous infusion 5
- Limit treatment to 7-10 days maximum, as extending beyond this carries no additional benefit 5
Essential Supportive Measures
- Provide IV fluid and electrolyte replacement with potassium supplementation of at least 60 mmol/day (hypokalaemia or hypomagnesaemia can promote toxic dilatation) 5
- Administer subcutaneous prophylactic low-molecular-weight heparin for thromboprophylaxis 5
- Correct electrolyte abnormalities and anemia 5
- Provide nutritional support if malnourished (enteral nutrition preferred over parenteral: 9% vs 35% complications) 5
Diagnostic Evaluation
- Perform unprepared flexible sigmoidoscopy and biopsy to confirm diagnosis and exclude CMV infection 5
- Obtain stool cultures and assay for C. difficile toxin 5
- If C. difficile detected, administer oral vancomycin and consider fecal microbial transplant; stop immunosuppressive therapy if possible 5
Rescue Therapy Decision Point
- Consider therapeutic alternatives for steroid-refractory disease (ciclosporin, tacrolimus, or infliximab) early—on or around Day 3 of steroid therapy. 5
- Do not delay decision-making, as patients remaining on ineffective corticosteroids suffer high morbidity 5
Alternative to Steroids
- IV ciclosporin 2-4 mg/kg/day monotherapy is as effective as IV methylprednisolone for acute severe UC and is useful in patients who should avoid steroids (steroid psychosis, concomitant osteoporosis, poorly controlled diabetes) 5
Multidisciplinary Care
- Patients are best cared for jointly by a gastroenterologist and colorectal surgeon 5
Staphylococcal Enterocolitis
Oral Vancomycin Therapy
- For staphylococcal enterocolitis (including methicillin-resistant strains), administer oral vancomycin 500 mg to 2 g daily in 3-4 divided doses for 7-10 days. 6
- Vancomycin must be given orally for enterocolitis; parenteral administration is not effective 6
- For pediatric patients (<18 years), usual dosage is 40 mg/kg/day in 3-4 divided doses for 7-10 days (not to exceed 2 g daily) 6
Monitoring Considerations
- Monitor serum vancomycin concentrations in patients with renal insufficiency, colitis, or those receiving concomitant aminoglycoside therapy 6
- Monitor renal function in patients >65 years of age during and following treatment 6
Common Pitfalls to Avoid Across All Types
- Never delay surgical consultation when signs of perforation or clinical deterioration are present—failure to remove necrotic bowel is often fatal in immunocompromised patients 3
- Do not use anticholinergic, antidiarrheal, NSAID, or opioid drugs in acute colitis as they may aggravate ileus and mask deterioration 5, 3
- Do not delay imaging in neutropenic or ICI enterocolitis patients with pain, fever, or bleeding 1
- Do not extend IV corticosteroid therapy beyond 7-10 days in severe UC without considering rescue therapy 5