Necrotizing enterocolitis

Learning objectives

Necrotizing enterocolitis (NEC) is a life-threatening intestinal disease that affects premature or very low birth-weight infants
It is the most common gastrointestinal (GI) emergency in NICUs → leading cause of long-term disability in preterm infants
Inflammation of the intestine leads to bacterial invasion causing cellular damage and cellular death, and necrosis of the colon and intestine → as NEC progresses, it may lead to intestinal perforation, causing peritonitis, sepsis, and death
Mortality up to 30%

Abdominal pain and distention
Changes in heart rate, blood pressure, and breathing
Diarrhea with bloody stool
Increased gastric residuals
Vomiting of bile
Lethargy
Feeding intolerance
Failure to thrive
Hyperglycemia
Temperature instability
In severe cases: Hypotension, disseminated intravascular coagulation, and metabolic acidosis

Bell’s stages of NEC

Stage I (suspected disease): Mild systemic signs (apnea, bradycardia, temperature instability, lethargy), mild GI signs (abdominal distension, increased gastric residuals, bloody stools), non-specific or normal radiologic signs
Stage II (definite disease): Mild systemic signs with additional GI signs (absent bowel sounds, abdominal tenderness), specific radiological signs (dilated loops of intestines, pneumatosis intestinalis or portal venous air), abnormal laboratory investigations (e.g., metabolic acidosis, thrombocytopenia)
Stage III (advanced disease): Severe systemic illness (with hemodynamic instability), additional GI signs (gross abdominal distension, peritonitis), severe radiological signs (pneumoperitoneum), additional laboratory findings (e.g., metabolic and respiratory acidosis, disseminated intravascular coagulation)

Abdominal infection: Peritonitis increases the risk of sepsis
Intestinal strictures: A stricture narrows the intestines
Short bowel (short-gut) syndrome: Results in malabsorption
Growth failure, poor neurodevelopmental outcomes, and developmental delay: Mainly in infants requiring surgery

Medical management will avoid surgery in 85% of cases
- Fluid resuscitation
- Stop enteral nutrition
- Decompress the stomach with a nasogastric tube
- Antibiotics
- Packed red blood cells (PRBC) and platelet transfusions
Surgery
- Exploratory laparotomy removal of the gangrenous bowel
- Ileostomy
- Peritoneal drain
Indications for surgery
- Perforation
- Obstruction
- Peritonitis
- Worsening acidosis
- Neonate becomes more septic

Premature infant considerations
Increased risk of aspiration: Bowel obstruction, dilated bowel loops, pneumatosis intestinalis
Associated multisystem derangements: Hypoxia, sepsis, hypovolemia, disseminated intravascular coagulation, thrombocytopenia, metabolic acidosis
Associated conditions: Birth asphyxia, hypotension, respiratory distress syndrome, patent ductus arteriosus, recurrent apnea, intestinal ischemia, systemic infections

Long-term survival depends on