1. Necrotising enterocolitis

2. Introduction
Necrotizing enterocolitis (NEC) is a serious disease of unknown cause and is charaterised by various degrees of mucosal or transmural necrosis of intestine.
Is the most common gastrointestinal medical/surgical emergency occurring in neonates.

3. Epidemiology
There is no consistent association between gender/season/socioeconomic status and rates of NEC .
However male VLBW babies have a higher mortality.
Mortality is higher in black infants with NEC (even when matching for birthweight and other characteristics) .
95% of NEC occurs after enteral feeds have been introduced .
Human milk is protective with a three to ten-fold reduction in NEC (compared to formula fed) .

4. Age at onset
The age at onset is inversely related to birth weight and gestational age.
mean age of 3 weeks in the <30 weeks
2 weeks for the weeks
5 days for >34 weeks and
2 days for full-term infant

5. Incidence
<1500gms 10%
gms 5%
>2500gms 2%

6. Pathogenesis:
Despite many years of research, its pathogenesis remains unknown.
Several factors appear to play either a primary or a secondary role:
infectious agents/toxins,
mesenteric ischemia/tissue hypoxia and
prematurity .

7. Risk factors Prematurity Perinatal asphyxia Shock
Cyanotic heart disease
Hypertonic formula
Too much – too fast formula feeding
Exchange transfusion
Congenital gi anomalies
Polycythemia

8. Premature infants are at risk because of immaturity of:
- Gastrointestinal motility
- Digestive ability
- Circulatory regulation
- Intestinal barrier function: If this is immature, or reduced, bacteria are able to penetrate the mucosal barrier and cause inflammation more easily. Immature goblet cells and an immature mucin layer may lead to increased permeability and breaching of the intestinal epithelial barrier.
- Immune defense

9. Infectious agents
Occasional epidemics of NEC have occurred in some nurseries, and have been associated with Klebsiella, E. coli, Clostridia, coagulase negative Staphylococcus, rotavirus, and coronavirus.

10. Symptoms feeding intolerance abdominal distension bloody stools apnea
lethargy
temperature instability
hypoperfusion

11. Signs Gastrointestinal Signs Systemic signs Respiratory failure
Increased abdominal girth
Visible intestinal loops
Obvious abdominal distention and decreased bowel sounds
Hematochezia (passage of bright red )
A palpable abdominal mass
Erythema of the abdominal wall
Systemic signs
Respiratory failure
Decreased peripheral perfusion
Circulatory collapse

12. Criteria for diagnosis (any 2)
Prefeed gastric aspirate volume of more than 50% of the last feed volume or abdominal distension ( increase in abdominal girth >2 cms).
Frank or occult blood and/or reducing substance in stool.
Radiological evidences of pneumatosis intestinalis /portal air /free air under the diaphgram.

13. Laboratory evaluation
Common laboratory abnormalities include
thrombocytopenia
leukocytosis
electrolytes imbalance
metabolic acidosis
hypoxia or hypercapnia
NEC is associated with bacteremia in approximately 30% of the cases, and a blood culture should be obtained before antibiotics are started.

14. Radiographic findings
 nonspecific
diffuse gaseous distension
asymmetric, disorganised bowel pattern
‘featureless’ loops
dilated bowel loops
bowel wall thickening
increased peritoneal fluid
diagnostic signs
pneumatosis intestinalis (virtually pathognomonic)
portal venous gas
pneumoperitoneum (although may not be due to NEC)

15. Pneumatosis intestinalis

16. Pneumatosis intestinalis

17. Normal (top) versus necrotic section of bowel

18. Resected portion of necrotic bowel

19. Picture of acute bowel necrosis seen in NEC

20. Differential diagnosis
Intestinal Volvulus
Gastroesophageal Reflux
Neonatal Sepsis
Intestinal Malrotation
Meningitis
Hospital Acquired Infection

21. Complications Pneumoperitoniun Localised peritonitis
Intestinal obstruction
Lactose intolerance
Short gut syndrome

22. Management Nil by mouth to rest the bowel .
NG or OG tube to decompress the bowel with low intermittent orogastric suction .
IV fluids TPN
IV antibiotics for days
Ampicillin/gentamicin or cefotaxime
Plus metronidazole or clindamycin
Treat shock, DIC etc.
Surgery if deteriorating or perforated/necrotic bowel suspected .
Intubation/ventilation for apnoea .
Serial bloods and abdominal x-rays.
Can restart oral feeds 7-10 days after pneumatosis clears.

23. Surgical Care In acute illness
Ischemic segment should be resected with construction of ileostomy or colostomy.
It is better to just drain the abdomen and perform a defunctioning enterotomy until the acute inflammation subsides,when definite resection is easier.
In recovery phase
Stricture.
Persistent malabsorption.

24. Patient Care Inpatient care Outpatient Care
Prolonged parenteral nutrition is essential to optimize the baby's nutrition while the gastrointestinal tract is allowed enough time for recovery and return to normal functioning. Prolonged parenteral nutrition may be associated with cholestasis and direct hyperbilirubinemia.
Outpatient Care
If a baby goes home with a colostomy, parents need thorough instruction regarding the baby's care.
Babies who have undergone intestinal resection may experience short-gut syndrome

25. Prognosis Overall the prognosis is poor.
Mortality of those undergoing medical treatment is about 20% .
Mortality of those coming to surgery is about 30% .
Amongst survivors about 30% develop ischaemic colonic strictures .

26. Prevention Feeding human milk (Start feeds slowly using low volume).
Small increments (20 ml/kg/day) when increasing feeds.
Antenatal steroids .
Ig A supplementation.
Arginine supplementation.
Oral antibiotics.
Probiotics.

27. Corticosteroids
Corticosteroids given to women in early labour help the babies' lungs to mature and so reduce the number of babies who die or suffer breathing problems at birth common serious neurological and abdominal problems, e.g. cerebroventricular haemorrhage and necrotising enterocolitis, that affect babies born very early.
New concepts in necrotizing enterocolitis. Current opinion in Pediatrics 2001;13:111-5