Necrotizing enterocolitis (NEC) is a disease that causes death and necrosis of intestinal tissue, typically affecting premature and formula-fed infants. It has an incidence of 3 cases per 1000 live births. Risk factors include prematurity, low birth weight, and enteral feeding. The exact cause is unknown but is likely multifactorial involving ischemia, reperfusion injury, and an exaggerated inflammatory response. Clinical presentation ranges from mild vomiting and feeding intolerance to systemic signs of shock. Management involves nil by mouth, IV fluids, antibiotics, and possible surgery for severe or perforated cases. Prognosis depends on severity but overall mortality is approximately 25%.

1. NECROTIZING
ENTEROCOLITIS
(NEC)
PRESENTER: DR. SHILULI MATE
FACILITATOR: DR. PHILLIPE

2. OUTLINE
• Definition
• Epidemiology
• Risk factors & etiology
• Pathogenesis
• Clinical presentation
• Investigation
• Management
• Prognosis

3. DEFINITION
• Death & necrosis of intestinal tissue
• Characterized by variable damage to the intestinal tract,
ranging from mucosal injury to full-thickness necrosis &
perforation
• Typically occurs in the 2nd - 3rd week of life in premature &
formula-fed infants. Occurs early in term infants (1-3days)

4. EPIDIMIOLOGY
• Most common GI medical/surgical emergency in
newborns
• Incidence is 3/1000 live births,
– 3/100 live birth in LBW
• 90% are premature
• Male: Female 1:1
• Blacks ˃ Whites

5. RISK FACTORS
• Prematurity ˂ 34 weeks
• LBW ˂ 1500g (approx. 10% )
• Term infant with pre-existing illness
• Enteral feeding of premature infants
– Hypertonic formula/enteral meds
– Breast milk protective compared to formula
NB : Rate of feeding & timing of initiation of feeds don’t change
rates of NEC

6. ETIOLOGY
• Exact cause not known
• Multifactorial: ischemia &/or reperfusion injury, exercabated by activation
of pro-inflammatory intracellular cascades
• Premature have immature bowels, weakened by low oxygen or blood flow
• Early feeding causes more stress to the lumen allowing bacteria that are
normally found in the intestine invade & damage the mucosa

7. Etiology cont.…
• The damage can affect a small segment of the
intestine or progress to affect a larger portion
• Common enteric pathogens: E. coli, Klebsiella, C.
perfiringes, S. epidermidis & rotavirus

8. PATHOGENESIS
• Multiple risk factors predispose to getting NEC
• An insult to the intestinal lumen initiates the
process
• Progression is due to stasis, vascular factors &
bacterial overgrowth
• May resolve or may progress to perforation

10. CLINICAL PRESENTATION
• History: Maternal risk factors – infections, PET, DM, drug abuse…
• Initial symptoms:
– Vomiting & diarrhea
– Delayed gastric emptying
– Feeding intolerance
– High gastric residuals
– Abdominal distension
– Frank occult blood in stools

11. Physical examination
• GI signs:
– Erythema of the abdominal wall
– Increased abdominal girth
– Visible intestinal loops
– Abdominal distention
– Change in stool patterns
– Hematocheza
– Palpable abdominal mass
– Reduced bowel sounds

12. PE cont.…

13. Systemic signs:
• Advanced disease will present with signs & symptoms
of:
– Respiratory failure - apnea
– Decreased peripheral perfusion
– Circulatory collapse - bradycardia
– Consumptive coagulopathy – bleeding diathesis
– Lethargy
– Temperature instability

14. DIFFERENTIAL DIAGNOSIS
• Intestinal malrotation
• Intestinal volvulus
• Bacterial meningitis
• Neonatal sepsis
• Ompahlitis
• Prematurity
• Volvulus
• UTI
• Apnea of prematurity

15. INVESTIGATIONS
• CBC: ↑WBC, ↓ANC ↓RBC, ↓PLT,
• Blood culture: Isolate the causative organisms
• Serum electrolytes: ↓Na,
• Stool: Occult blood
• ABG: ↓serum bicarbonate (˂20mEq/l), lactic
acidosis

16. Abdominal Imaging
• Mainstay diagnostic is plain abdominal x-ray
• Plain abdominal x-ray features for NEC:
– Pneumatosis intestinalis (gas cyst in the bowel wall) –
pathognomic of NEC
– Dilated loops of bowel
– Portal air – poor prognostic sign
– Free air (if perforated) – lat. decubitus view

17. Abdominal x-ray

18. Abdominal ultrasound
• Good for bedside demonstration of ascites
• May show portal air more clearly than KUB

19. Modified Bells Staging for NEC

20. MANAGEMENT
• Initial course of treatment entails
– Nil per oral – stop all enteral feeds
– Decompression – NGT
– Initiate broad-spectrum antibiotics (ampicillin,
aminoglycoside, or 3rd generation cephalosporin &
clindamycin or metronidazole
– IVF
• The definitive treatment approach will depend
on the stage:

21. Treatment cont..
Stage IA & 1B:
• NPO
• Antibiotics for 3/7
• IVF, including TPN
Stage IIA & IIB:
• NPO & TPN
• IVF resuscitation for RS & CVS support
• Antibiotics for 2/52
• Surgical consult

22. Treatment cont.…
Stage IIIA &B III:
• NPO & TPO for 2/52
• IVF resuscitation
• Inotropes
• Ventilatory support
Stage IIIB:
• Surgery - indicated for perforation &/or peritonitis

23. Treatment cont…
• Surgery involves:
– Resection of necrotic tissue
– Colostomy/ileostomy performed
– Anastomosis of bowel segments done after
infection is eradicated

24. COMPLICATIONS
• Intestinal perforation
• Intestinal strictures
• Peritonitis
• Sepsis
• Malabsorption

25. Prognosis
• Depends on severity of the illness
• Death rate approximates 25%
• Early aggressive treatment improves the outcome
• Most infants recover fully & never have feeding
problems
• Few cases can resulting bowel narrowing and scarring
causing further obstruction/blockage

26. References
1. Williams, N. S., Bulstrode, C. J., &
O'Connell, P. R. (2008). Bailey & Love's
short practice of surgery. Crc Press.
2. Medscape
3. Slideshare