11/14/24, 10\:54 AM Necrotising Enterocolitis

Necrotising Enterocolitis

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Necrotising enterocolitis (NEC)\: most common surgical emergency in neonates; acute in
preterm infants; leads to bowel necrosis, multi-system organ failure, and can be life-threatening.
Incidence\: occurs in around 12% of low birth weight infants (\<1500g); increasing due to advancements in neonatal intensive
care.
Aetiology\: multifactorial; exact cause unknown; damage to intestinal mucosa from vascular insults, toxins, infection, and
genetic factors; pathogenic colonisation of normal commensal bacteria.
Risk factors\: prematurity (\<32 weeks), low birth weight, abnormal dopplers, prolonged antibiotic treatment, enteral feeding,
cow’s milk formula, congenital heart disease.
Symptoms\: new feed intolerance, vomiting (bilious or increased NG aspirate), distended tender abdomen, haematochezia.
Examination
intestinal loops, signs of sepsis (lethargy, temperature instability, haemodynamic instability).
Di
Investigations\: blood tests (FBC, CRP, blood cultures), blood gas (raised lactate or acidosis), abdominal ultrasound (air in
portal system, ascites, perforation), abdominal X-ray (thickened bowel wall, dilated loops, pneumatosis intestinalis, Rigler’s
sign).
Management\: urgent review by paediatric surgeon, keep nil by mouth (may require total parenteral nutrition), bowel
decompression (NG tube), manage sepsis, IV
circulatory support and ventilation if needed.
Surgical management\: required in 20-50% of cases; indicated by evidence of perforation; laparotomy to remove perforated
and necrotic bowel.
Complications\: general (bowel perforation, DIC, sepsis, adverse neurodevelopmental outcomes), post-operative (short
bowel syndrome, intestinal strictures, enterocolic
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Introduction

Necrotising enterocolitis (NEC) is the most common surgical emergency in neonates.
1
NEC is an acute in
organ failure and is life-threatening. Prompt recognition of NEC and appropriate treatment is vital.
2
NEC occurs in around 12% of low birth weight infants (\< 1500g). Due to the advancement of neonatal intensive care, more
at-risk infants are surviving long enough for the disease to develop and so the incidence of NEC is increasing.
3

Aetiology

NEC is a multifactorial condition and the exact cause is unknown. Damage to the intestinal mucosa can occur due to
vascular insults, toxin exposure, infection and genetic factors.
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This damage allows pathogenic colonisation of normal commensal bacteria. However, some outbreaks of NEC have been
isolated to a pathogenic organism, such as E s c h e r i c h i a c o i l .
3

Risk factors

85% of NEC cases occur in infants who are premature (especially \<32 weeks), or with low birth weight.
3
Other risk factors include\:
Abnormal dopplers (measuring blood
Antibiotic treatment lasting longer than 10 days or multiple courses of antibiotics
Enteral feeding
Use of cow’s milk formula (breastfeeding is protective against NEC)
Congenital heart disease

Clinical features

History

NEC usually presents at a corrected gestational age of 30 - 33 weeks (i.e., in weeks 3 - 4 of life in a baby born at 28 weeks).
Typical symptoms of NEC include\:
4
A new feed intolerance
Vomiting (which may be bilious) or increasing volume of NG aspirate
Distended abdomen, which becomes tender and tense
Haematochezia (fresh blood in the stools)
Other important areas to cover in the history include\:
Feeding history\: infants with NEC often have a new onset feed intolerance. Ask about rate of feeding, volume taken,
vomiting after food, any changes in food (e.g. from breast to bottle and changes in formula).
3
Bowel movements\: ask about normal bowel habits. Has meconium been passed? How often do they open their bowels?
This can be quanti
Past medical history\: especially respiratory/cardiac history and history of previous infections.
Pregnancy history\: it is important to take a thorough pregnancy history from the parent/carer.
Family history\: ask about a family history of illness in the newborn period. Many neonatal conditions, including NEC, have
a genetic predisposition.
Pregnancy history
Key areas to cover in the pregnancy history include\:
Was the mother under hospital-led maternity care (and if so, why)?
Was this a high-risk pregnancy?
Did the mother or baby develop any problems during the pregnancy?
Were any antenatal scans abnormal?
Pregnancy gestation?
Method of birth?
Any complications with the birth (both mother and infant)?

Clinical examination

All unwell infants require a thorough clinical examination. See the Geeky Medics OSCE guide to performing a newborn
baby assessment.
Typical clinical
3
Abdominal distension, tender to palpation and can feel tense or "
wooden"
Reduced bowel sounds
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Palpable abdominal mass
Visible intestinal loops
Signs of sepsis (e.g. lethargy, temperature instability, haemodynamic instability)

Di

The clinical presentation of NEC can appear similar to several other conditions.
Table 1. Di
Condition Clinical features
Can develop as a complication of NEC. Bacteria can
translocate through the in
circulation causing sepsis.
Sepsis
Other common causes of neonatal sepsis include group B
strep infection, premature or prolonged rupture of
membranes, chorioamnionitis and maternal septicaemia.
6
Intussusception occurs in infants aged between 3 months

Investigations

Laboratory investigations

Relevant laboratory investigations include\:
Baseline blood tests (FBC, CRP)\: CRP may be raised and there may be thrombocytopenia and neutropenia.
Blood cultures\: non-speci
is isolated this can be useful for guiding treatment.
9
Blood gas\: may show a raised lactate or acidosis.

Imaging

Relevant imaging investigations include\:
Abdominal ultrasound\: ultrasound is a safe
that are indicative of NEC include air in the portal system, ascites and perforation.
Abdominal X-ray\:
wall, dilated bowel loops
is diagnostic of NEC).
10
If the bowel has perforated, Rigler’s sign may be visible. This occurs when both sides of the bowel wall are visible due to
the presence of gas inside the lumen and within the peritoneal cavity.
11
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Figure 1. X-ray of an infant with necrotising enterocolitis.
13

Management

Neonates with suspected NEC require urgent review by a paediatric surgeon.

Medical management

Principles of medical management for NEC include\:
4
Keep the infant nil by mouth (total parenteral nutrition may be required)
Consider bowel decompression with a nasogastric tube
Assess and manage sepsis
Intravenous
Intravenous antibiotics (broad-spectrum cover is recommended as
Circulatory support and ventilation may be required

Surgical management

Surgical management is required in 20-50% of cases.
2
According to the modi
laparotomy is carried out to remove the perforated and necrotic bowel from the abdomen.
5

Complications

General complications of NEC include\:
3
Bowel perforation
Disseminated intravascular coagulation
Sepsis
Adverse neurodevelopmental outcomes (especially in infants who undergo surgery)
Post-operative complications of NEC include\:
3
Short bowel syndrome
Formation of intestinal strictures
Enterocolic
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Abscess formation
In infants who undergo surgery for NEC, a 29% post-surgical mortality rate has been reported at one year.
12

References

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Sha
Patient UK. N e c r o t i s i n g E n t e r o c o l i t i s . Published 2016. Available from\: [LINK]
Barry. P a e d i a t r i c I n t e n s i v e C a r e . Published 2010.
National Institute for Health and Care Excellence. NG143\: T r a
2019. Available from\: [LINK]
NICE. Q u a l i t y S t a n d a r d 7 5 \: N e o n a t a l I n f e c t i o n . Published 2014. Available from\: [LINK]
Patient UK. I n t u s s u s c e p t i o n i n C h i l d r e n . Published 2016. Available from\: [LINK]
Patient UK. H i r s c h s p r u n g’ s D i s e a s e . Published 2018. Available from\: [LINK]

Coggins et al. I n f e c t i o u s C a u s e s o f N e c r o t i z i n g E n t e r o c o l i t i s . Clin Perinatol. Published 2015. Available from\: [LINK]
Lissauer. I l l u s t r a t e d T e x t b o o k o f P a e d i a t r i c s . Published 2018.
Attention De
Radiopedia. R i g l e r s i g n . Published 2020. Available from\: [LINK]
Autism Spectrum Disorder (ASD)
Allin et al. O n e- y e a r o u t c o m e s f o l l o w i n g s u r g e r y f o r n e c r o t i s i n g e n t e r o c o l i t i s \: a U K -w i d e c o h o r t s t u d y . ADC Fetal Biliary Atresia
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Bronchiolitis
Figure 1. WikiRad. X -r a y o f a n i n f a n t w i t h n e c r o t i z i n g e n t e r o c o l i t i s . License\: [CC BY-SA]. Available from\: [LINK].
Cerebral Palsy
& Neonatal

Reviewer

Test yourself

Dr Amanda Gilbert
Paediatric trainee