Necrotising Enterocolitis
Key points
Statistics
Age of presentation is inversely proportional to gestational age. E.g term babies will get it in first few days of life
Disease course in a term neonate can be much more severe
Spontaneous intestinal perforation (SIP) more common in extreme prematurity and low birthweight
Breast milk 3x more protective - Early trophic feeds decrease likelihood of sepsis and poor growth, and do not make more susceptible to NEC
20-40% need surgery
Mortality for surgery is up to 50%
Aetiology
NEC: Lack of motility, mucosal barrier, vascularity and absorption, increased intra-luminal pressure
SIP: Premature gut, steroids and NSAIDS (+ maternal NSAIDs)
Thrombocytopenia in most cases - gram negative organisms release endotoxin which binds platelets
Important examination points
Look for discolouration
Desaturation and bradycardia on palpation indicate tenderness
Palpate for mass
Colonic NEC may not manifest abdominal signs
Modified Bell staging criteria
Stages IA (suspected) to IIIB (perforation)
Based on systemic findings, abdominal examination and X-ray appearance
Microbiology
SIP: Candida and coagulase-negative staphylococcus epidermidis -
Perforated NEC: Gram -ve bacilli - E.Coli, Klebsiella. Clostridium
Histology
Coagulative necrosis = NEC
Haemorrhagic necrosis = SIP
Radiology
Linear pneumatosis is subserosal vs cystic or bubbly pneumatosis which is submucosal
Soap bubble appearance in neonates is unlikely to be due to stool
If gasless abdomen - can get USS looking for perfusion, peristalsis, free air, fluid
Do not manage patient based on a single X-ray (unless clear pneumoperitoneum), look at all previous films
A quarter of perforations are not visible on X-ray
Fixed loop = necrosis needing surgery in 50% of cases
Laparotomy vs drain insertion
J Paediatric Surgery 2010 NET trial
RCT of infants <1000g 35 vs 34 Drain vs primary laparotomy
Drain does not improve clinical parameters or organ dysfunction prior to laparotomy and had worsening cardiovascular status. 74% of drain patients needed laparotomy
J Paediatric Surgery 2019 - NEC
Retrospective analysis of 528 infants <1000g. Laparotomy vs drain. No differences in mortality or hospital stay. But higher risk of short gut with laparotomy
J Paediatric Surgery 2019 - SIP
Multicentre retrospective comparison of primary drain vs laparotomy
No differences in outcomes. 30% of drain patients needed laparotomy. 10% of laparotomy patients needed an additional 3rd procedure due to complications. No way to confirm diagnosis in drain-only patients
Recycling/refeeding through mucus fistula
Should have distal loopogram/contrast enema first
J Paediatric Surgery 2016 Case control
Comparison of 77 refeeding patients vs 15 non. Refeeding was safe, less bowel discrepancy, less anastomotic leaks, less TPN complications
J Paediatric Surgery 2015 observational of 23 patients
3 perforations of mucus fistula, 1 bleed, 1 death due to refeeding
Outcomes of NEC
More likely to have neurodevelopmental impairment compared to non-NEC at 18-22 months
Recurrent NEC in 10%
Overall mortality 25-30%, 50% if surgical
Standard scenario
Neonate with NEC
Decision to operate
Is the patient fit for an operation?
Is it in their best interests i.e. there comorbidities such as major intra-ventricular haemorrhage and poor prognosis?
If above criteria satisfied -
Absolute indication: Perforation
Relative indications:
Mass
Failure to improve with medical management
Fixed loop >72 hours
Sudden catastrophic deterioration with abdominal signs
2021 BAPS CASS - Failed medical management as indicator for surgery has worse outcomes - leads to 30h delay in surgery compared to perforation
Laparotomy
RUQ transverse incision or RLQ/LUQ if palpable liver or <1kg
Washout contamination
Assess length of bowel - how much is to be categorised: necrotic, viable, indeterminate
Resect necrotic areas, leave viable areas (unless pan-intestinal necrosis - close and palliate in this situation)
Assess stability - if unstable clip and drop, laparostomy. If stable - assess indeterminate bowel - if focal NEC, can resect indeterminate - if multifocal defunction the indeterminate length - proximal jejunostomy
Can anastomose if stable and minimal contamination, most likely scenario is to do stoma at site of resection
If terminal ileum requires resection but caecum unaffected -better to oversew and drop in distal end rather than cause damage mobilising to bring out as mucus fistula
If previous peritoneal drain - site may make a good place to bring out a stoma
Post operative management
Continue nil enteral and IV antibiotics for 10-14 days
Post op intra-abdominal collection - often no need to drain, will come out of wound if severe
If clip and drop - relook in approximately 48 hours - check viability of remaining bowel, resect non-viable. If indeterminate, defunction with stoma. Can anastomose if healthy
If stoma - will need to plan closure (consider recycling first - see above). No consensus yet for early closure vs closure at term etc.
Should have distal loopogram/contrast enema before stoma closure to ensure distal segment patent
If stricture - will need full laparotomy to close stoma
If patent ductus arteriosus requiring surgery, close it before stoma, as risk of post ligation NEC
References
Hirschl, Ron, et al., editors. "Necrotizing Enterocolitis." Pediatric Surgery NaT, American Pediatric Surgical Association, 2021. Pediatric Surgery Library, www.pedsurglibrary.com/apsa/view/Pediatric-Surgery-NaT/829043/all/Necrotizing_Enterocolitis.
Hirschl, Ron, et al., editors. "Spontaneous Intestinal Perforation." Pediatric Surgery NaT, American Pediatric Surgical Association, 2020. Pediatric Surgery Library, www.pedsurglibrary.com/apsa/view/Pediatric-Surgery-NaT/829044/all/Spontaneous_Intestinal_Perforation.
Rees CM, Eaton S, Khoo AK, Kiely EM; Members of NET Trial Group; Pierro A. Peritoneal drainage does not stabilize extremely low birth weight infants with perforated bowel: data from the NET Trial. J Pediatr Surg. 2010 Feb;45(2):324-8; discussion 328-9. doi: 10.1016/j.jpedsurg.2009.10.066. PMID: 20152345.
Ahle S et al. Multicenter retrospective comparison of spontaneous intestinal perforation outcomes between primary peritoneal drain and primary laparotomy. J Pediatr Surg. 2020 Jul;55(7):1270-1275. doi: 10.1016/j.jpedsurg.2019.07.007. Epub 2019 Jul 19. PMID: 31383579.
Yanowitz TD, CHND Surgical NEC Focus Group et al. Does the initial surgery for necrotizing enterocolitis matter? Comparative outcomes for laparotomy vs. peritoneal drain as initial surgery for necrotizing enterocolitis in infants <1000 g birth weight. J Pediatr Surg. 2019 Apr;54(4):712-717. doi: 10.1016/j.jpedsurg.2018.12.010. Epub 2019 Jan 19. PMID: 30765157.
Lau EC, Fung AC, Wong KK, Tam PK. Beneficial effects of mucous fistula refeeding in necrotizing enterocolitis neonates with enterostomies. J Pediatr Surg. 2016 Dec;51(12):1914-1916. doi: 10.1016/j.jpedsurg.2016.09.010. Epub 2016 Sep 15. PMID: 27670958.
Haddock CA, Stanger JD, Albersheim SG, Casey LM, Butterworth SA. Mucous fistula refeeding in neonates with enterostomies. J Pediatr Surg. 2015 May;50(5):779-82. doi: 10.1016/j.jpedsurg.2015.02.041. Epub 2015 Feb 19. PMID: 25783364.
Bethell GS, Knight M, Hall NJ; BAPS-CASS NEC Investigator Group on behalf of BAPS-CASS. Surgical necrotizing enterocolitis: Association between surgical indication, timing, and outcomes. J Pediatr Surg. 2021 Oct;56(10):1785-1790. doi: 10.1016/j.jpedsurg.2021.04.028. Epub 2021 May 2. PMID: 34090670.
Thakkar HS, Lakhoo K. The surgical management of necrotising enterocolitis (NEC). Early Hum Dev. 2016 Jun;97:25-8. doi: 10.1016/j.earlhumdev.2016.03.002. Epub 2016 Mar 29. PMID: 27032753.