Ira Shah
Medical Sciences Department, Pediatric Oncall, Mumbai

NEC is a syndrome of acute intestinal necrosis. The etiology is unknown and pathogenesis is complex and multi factorial. It is the most common serious surgical disorder among infants in NICU & a significant cause of neonatal morbidity and mortality. It is seen in 2.5% of all NICU admissions and has an overall mortality rate of 30-40% with mortality increasing to more than 80% in neonates less than 1kg.

There are various predisposing factors:

• Role of immature Gastrointestinal host defenses
• Role of infectious agents & bacterial toxins
• Role of inflammatory mediators
• Role of oxygen radicals & ischemia reperfusion injury

Common sites are terminal ileum and ascending colon

• Symptoms may appear within 96 hrs after initiation of feeds
• Majority of cases occur within first 10 days of life
• Onset may be insidious / explosive / delayed
• Earliest signs : abdominal distension, retention of milk in a sick-looking LBW infant.
• Clinical triad : Abdominal. Distension + GI bleeding + Pneumatosis intestinalis
• Signs of functional Intestinal obstruction : Abdominal distension, progressive decreased Peristalsis, Bilious vomiting, hematemesis and blood in stools
• Signs of peritonitis & perforation: Ascites, erythema & edema of abdominal wall, localized mass or rigidity
• Systemic signs : respiratory distress, Apnea / bradycardia, Lethargy, thermal instability, irritability, poor feeding, hypotension (shock), oliguria, bleeding diathesis, sclerema

Stage	Clinical features	X-ray	Survival (%)
Suspect NEC	Mild abdominal distension  Stasis  Vomiting  Poor feeding	Mild ileus	100%
DefiniteNEC	Marked abdominal distension  GI bleeding	Definite ileus   Pneumatosis intestinalis	95%
Advanced      NEC	DIC   Shock   Sclerema   Brownish Peritoneal aspirate	Fixed dilated loop of intestine   Portal vein gas   Pneumoperitoneum	50%

1. Serial X-rays of abdomen: Fixed bowel loop, Appearance of mass, Pneumatosis intestinalis, Portal or hepatic venous air, Pneumoperitoneum
2. Stool examination: Occult blood, reducing substances for unabsorbed lactose, Culture for aerobic / anaerobic bacteria
3. Blood: Electrolytes, Hematocrit, Coagulation status , Culture, ABG. Watch for triad of thrombocytopenia, severe refractory hyponatremia and acidosis.
4. USG: Micro bubbles of gas in portal vein
5. Hydrogen breath test

Medical

Surgical

Respiratory:      Supplement O 2      Mechanical ventilatory support CVS:      Fresh frozen plasma       Low doses dopamine Metabolic:       NaHCO Nutrition:     Stop oral feedings (7-14 days)       TPN instituted (90-110 cal/kg/d) Antibiotics - For 7-14 days. Broad spectrum Hematological:       Platelet transfusions < BR>      Packed RBCs       Vitamin K CNS :       Treat IVH, meningitis, Seizures Renal:       Fluid therapy

Indications Bowel perforation Full thickness necrosis of bowel wall as evidenced by dilated loop of intestine unchanged in position > 24 hrs. Peritonitis. Aspiration of brown colored fluid is indicative of intestinal gangrene. Surgical treatment: Excision of necrotic area & end-to-end anastomosis.

Recurrent NEC is 4%.

• Strictures (20%) most common in large bowel
• Enteric fistulas
• Short bowel syndrome (following surgery)
• Malabsorption & chronic diarrhea
• Dumping syndromes - loss of terminal ileum
• Fluids electrolyte losses (with ileostomy)
• Parenteral nutrition associated hepatic disease
• Developmental delay.

1. Corticosteroids - Prenatal / Postnatal
• Lower incidence of NEC in mothers of preterm who received
  dexamethasone antenatally.
2. Feeding regimen
• Breast feeding
• Acidified feeds
• Small iso-osmolar feeds with gradual increase in feeds
3. Oral Immunoglobulins (IgA & IgG)
• Enhances intestinal immune defenses
4. Reduce incidence of:
• Preterm delivery
• Prevent predisposing factors.

1. Pneumonia & sepsis
2. Surgical abdominal catastrophes


• Malrotation with obstruction
• Malrotation with midgut volvulus
• Intusussception
• Ulcer
• Gastric perforation
• Mesenteric vessel thrombosis
  
  
3. Infections enterocolitis with diarrhea
4. Inherited metabolic disease
5. Feeding intolerance
6. Systemic candidiasis

Last updated: 1-05-2007