What is the recommended management for necrotising enterocolitis in a preterm infant born before 32 weeks gestation or weighing less than 1500 g?

Management of Necrotising Enterocolitis in Preterm Infants <32 Weeks or <1500g

Immediately implement bowel rest, broad-spectrum antibiotics (ampicillin + gentamicin + metronidazole), aggressive fluid resuscitation, and nasogastric decompression, with urgent surgical consultation if perforation or clinical deterioration occurs. 1, 2, 3

Immediate Medical Management

Bowel Rest and Decompression

• Discontinue all enteral feeds immediately to prevent further intestinal injury and allow the bowel to recover 1, 2, 3
• Insert a nasogastric tube for continuous gastric decompression to prevent distension and reduce perforation risk 1, 3
• Maintain complete bowel rest until clinical improvement is documented and imaging shows resolution of pneumatosis 2, 3

Fluid Resuscitation and Hemodynamic Support

• Provide aggressive intravenous fluid resuscitation to address the hypovolemia that commonly accompanies NEC and prevent progression to septic shock 1, 3
• Monitor closely for signs of sepsis and septic shock including hypotension, metabolic acidosis, thrombocytopenia, and neutropenia 1, 3
• Provide hemodynamic support as needed with vasopressors if fluid resuscitation alone is insufficient 1

Antibiotic Therapy

• Start broad-spectrum intravenous antibiotics immediately after obtaining blood cultures 1, 3
• First-line regimen: ampicillin + gentamicin + metronidazole is the most frequently used combination for pediatric complicated intra-abdominal infections 1, 3
• Alternative regimens if first-line unavailable: ampicillin + cefotaxime + metronidazole, or meropenem as monotherapy 1, 3
• Dose gentamicin based on lean body mass and estimated extracellular fluid volume to optimize efficacy and minimize toxicity in these vulnerable infants 3

Surgical Evaluation and Intervention

Indications for Surgery

• Obtain urgent surgical consultation for any infant with suspected or confirmed perforation 1, 2, 3
• Pneumoperitoneum on radiograph is an absolute indication for operative intervention 3
• Clinical deterioration despite maximal medical therapy (worsening acidosis, persistent hypotension, progressive abdominal wall erythema or edema) warrants surgical exploration 3

Surgical Approach

• For very low birth weight infants with confirmed perforation, peritoneal drainage can serve as a temporizing measure before definitive surgery 3
• Definitive surgery consists of bowel resection with either stoma creation or primary re-anastomosis depending on the extent of disease and infant stability 3
• Approximately 30% of NEC cases require surgical intervention for intestinal necrosis and perforation, while 70% can be managed nonoperatively 3

Nutritional Support During Acute Phase

Parenteral Nutrition

• Provide total parenteral nutrition during the period of complete bowel rest 1, 2
• Ensure minimum amino acid intake of 1.0 g/kg/day to prevent negative nitrogen balance 2, 3
• Provide 30-40 Kcal per 1g amino acids to guarantee proper amino acid utilization 2, 3
• Include taurine in amino acid solutions, though optimal dosing remains uncertain 2, 3
• Monitor for parenteral nutrition-associated complications including cholestasis 1

Blood Product Support

• Consider blood transfusion for significant gastrointestinal bleeding causing anemia or hemodynamic compromise 1
• Withhold enteral nutrition during and immediately after transfusion to reduce the risk of transfusion-associated NEC 1

Reintroduction of Feeds

Timing and Approach

• Consider arginine supplementation when reintroducing feeds as it may help prevent recurrence of NEC 1, 2, 3
• Advance feeds slowly and cautiously once clinical signs have resolved and imaging shows improvement 2

Prevention Strategies

Probiotic Prophylaxis

• Consider probiotic supplementation for prevention, particularly combinations of Lactobacillus spp. and Bifidobacterium spp., which have shown high-quality evidence for reducing severe NEC and mortality 1, 2, 3
• Specific effective combinations include: L. rhamnosus ATCC 53103 + B. longum subsp infantis, L. casei + B. breve, L. acidophilus + B. longum subsp infantis, and L. acidophilus + B. bifidum 3
• Probiotics may reduce the risk of NEC in very preterm or VLBW infants (RR 0.54,95% CI 0.46 to 0.65), though evidence certainty is low 4

Important Caveat for Extremely Preterm Infants

• For extremely preterm or extremely low birth weight infants, probiotics may have little or no effect on NEC (RR 0.92,95% CI 0.69 to 1.22), with low certainty evidence 4
• Exercise caution when extrapolating probiotic benefits to the most immature infants, as data are limited in this population 4

Prognosis

Survival Rates

• Overall survival for NEC is approximately 95% unless the entire bowel is involved 1, 2, 3
• When NEC involves the entire bowel (approximately 25% of cases), mortality increases dramatically to 40-90% 1, 2, 3
• Among neonates requiring surgery, mortality rates are estimated at 20-30% 5

Incidence by Gestational Age

• Incidence varies significantly by gestational age: 10-20% at 23-24 weeks, 5-10% at 25-27 weeks, and <5% at ≥28 weeks 3

Critical Pitfalls to Avoid

Medication-Related Risks

• Avoid proton pump inhibitors and H2 antagonists when possible, as acid suppression may be a risk factor for NEC in preterm infants 6, 7
• Minimize early antibiotic exposure when not clinically indicated, as this can alter the microbiota and increase NEC risk 7
• Avoid thickening feedings in preterm infants due to increased risk of necrotizing enterocolitis 6

Monitoring Considerations

• Do not delay surgical consultation when clinical deterioration occurs despite medical management 1, 2, 3
• Monitor for late complications including intestinal stricture, which occurs in 15-35% of recovered infants 8
• Glutamine supplementation is not recommended for infants up to two years of age with NEC 2