Necrotizing Enterocolitis (NEC)

Presentation

• Prematurity (highest risk factor)
• Feeding intolerance, increased gastric residuals, emesis (often bilious)
• Abdominal distension and tenderness
• Bloody stools (gross or occult)
• Systemic signs: apnea, bradycardia, lethargy, temperature instability, hypotension

Initial Workup

• Abdominal Radiograph (AP and Left Lateral Decubitus) - evaluating for pneumatosis intestinalis, portal venous gas, or pneumoperitoneum
• CBC with differential (look for leukopenia, thrombocytopenia)
• C-reactive protein (CRP) or procalcitonin
• Blood culture and consider CSF/urine if clinically indicated
• Arterial blood gas, serum lactate, and comprehensive metabolic panel (hyponatremia, metabolic acidosis)

Diagnostic Staging (Bell's Criteria)

• Stage I (Suspected): Mild systemic signs, feeding intolerance, normal or mildly dilated bowel loops.
• Stage II (Definite): Systemic illness, gross bloody stools, pneumatosis intestinalis on KUB.
• Stage III (Advanced): Severe sepsis/shock, disseminated intravascular coagulation (DIC), pneumoperitoneum indicating bowel perforation.

Management Protocol

• NPO (bowel rest) and immediate gastric decompression (Replogle/NG tube to continuous low suction)
• Initiate broad-spectrum IV antibiotics (e.g., Ampicillin, Gentamicin, plus Metronidazole or Clindamycin)
• Aggressive fluid resuscitation, inotropic support if hypotensive, and correct metabolic derangements
• Serial abdominal exams and KUBs (every 6-12 hours depending on acuity)
• Urgent pediatric surgery consultation (absolute indication for surgery is pneumoperitoneum or necrotic bowel)

Nutritional & GI Surgical Protocol

• NPO protocol: Replogle or Salem sump exactly at 10-14 cm mark hooked to low continuous suction (20-40 mmHg).
• TPN Initiation: Start amino acids at 2-3 g/kg/day, lipids at 1 g/kg/day within 24 hours of NPO status.
• X-Ray monitoring: Cross-table lateral and AP abdominal decubitus Q12h when concerned for perforation.
• Monitor daily abdominal girth measurements accurately marked by an indelible pen line at the umbilicus.
• Guaiac test all macroscopic bloody stools immediately.

Standardized Discharge & Follow-Up Criteria

• Adequate weight gain explicitly > 15-30g/day over a continuous 3-5 day period.
• Maintenance of temperature in an open crib with standard clothing for 48 hours.
• Successful completion of the 90-120 minute Infant Car Seat Challenge.
• Caregiver successfully completed CPR training, rooming-in, and independent medication administration.
• Referrals placed for High-Risk Infant Follow-Up Clinic, Early Intervention (PT/OT), and appropriate sub-specialists.

Diagnostic & Management Algorithm

• Feeding Intolerance Algorithm: [START] Gastric residual > 50% of 3-hour feed volume -> [DECISION] Bilious (green) aspirate? -> [YES] STOP feeds, insert Repogle, order stat KUB & Upper GI (rule out malrotation) -> [NO] Assess abdomen, if soft, re-feed residual and hold next feed or reduce volume by 20%

References

1. Neu J, Walker WA. Necrotizing enterocolitis. N Engl J Med.
2. Gephart SM, McGrath JM, Effken JA, Halpern MD. Necrotizing enterocolitis risk: state of the science. Adv Neonatal Care.