Necrotizing Enterocolitis
NICU Night Team Curriculum
Necrotizing Enterocolitis:
Objectives
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Define Necrotizing Enterocolitis (NEC)
and it’s pathophysiology.
Know the concerning clinical findings
on exam.
Review the classification of NEC.
Know the initial work up of an infant
suspected of having NEC
Know the initial management of NEC.
You are on call…
• You just got paged to come to the bedside of an ex-29
week male (DOL 15) who started having repeated
episodes of bradycardia and O2 desaturation and is
noted as having a distended abdomen. The patient
was recently started on small bolus feeds.
• Born to G1P1 mother via emergency c-section
secondary to pre-eclampsia. Pregnancy and
serologies otherwise unremarkable.
• Past medical history notable for RDS
• Birth weight: 1100 g
• Apgars 8/9 at birth, Neopuff in delivery room, currently
on CPAP.
Physical exam
• T:36.5C, P:90, RR:45, MAP:33, SpO2: 78%
• Gen/Head: Pale, AFOSF, atraumatic.
• CV: Bradycardia, NL S1/S2, No murmur. Cap
refill ~3 sec
• Pulm: CTAB, No rales/rhonchi.
• Abd: Firm, Tender, Distended, Dull color of
abdomen. Bowel sounds absent.
• Skin: No rash, petechiae or purpura. Noncyanotic.
Necrotizing Enterocolitis
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What is it?
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Disorder involving inflammation and ischemic
necrosis of intestinal walls.
Exact cause is uncertain. Popular theories include
infection, inadequate perfusion of gut.
Why is it important to identify NEC as early as
possible?
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NEC is a progressive disease with mortality rates
from 15-30% (inversely related to gestational age
and birth weight)
Epidemiology
• Occurs in 1-3 out of 1000 live births
• Males = Females
• Ethnic Incidence: Black > White >
Hispanic infants
• While it is more common in premature,
VLBW infants (<1500g), 13% occur in
term infants (often with preexisting illness).
Staging NEC – Bell’s Classification
Stage Clinical findings
Radiographic findings
I: Suspected NEC
Ia
Temp instability, apnea, lethargy,
increased residuals, abd distention.
Ib
See above. + grossly bloody stool.
Normal or mild ileus.
II: Proven NEC
IIa
IIb
See above. + absent bowel sounds. +abd Intestinal dilation, ileus,
tenderness. Appear mildly ill.
ascites, pneumatosis
intestinalis.
See above. Appear moderately ill.
+metabolic acidosis. +thrombocytopenia.
III: Advanced NEC
IIIa
See II. Bowel intact. Hypotension,
bradycardia, apnea. +peritoneal signs.
DIC, neutropenia.
IIIb
See III. + Bowel perforation.
Portal venous gas.
Pneumoperitoneum
(football sign) – specific
for stage IIIb.
Risk Factors
• VLBW infants
• Prematurity – inadequate perfusion gut
mucosa
• Aggressive advancement of enteral
feeding.
• Hyperosmolarity of solutions
• Bacterial overgrowth
Back to our case…
• You just got paged to come to the bedside
of an ex-26 week male (DOL 32) who just
had a bilious residual and is noted as
having a distended abdomen. The patient
was recently started on small bolus feeds.
• What visual findings would increase suspicion for
NEC?
• What physical exam findings would make you worried
about NEC?
What clinical findings should make
you concerned?
• Dull, dusky-colored,
distended abdomen
• Symptoms of sepsis
(temp instability, poor
perfusion, A/B/D,
lethargy)
• Large, bilious residuals
• Bloody stool
• Hypoactive/absent bowel
sounds
• Abdominal tenderness
http://www.cincinnatichildrens.org/research/di
v/neonatology/research-areas/clinicalinvestigations.htm
Initial work up: what to look for
Labs: Findings associated with NEC
• CBC
– Thrombocytopenia
– Neutropenia (<1500/microL) –poor
prognosis
• DIC panel (PT/INR, PTT, Fibrinogen,
D-dimer)
– Elevated PT/INR, PTT, D-dimer
– Decreased Fibrinogen
• BMP (may have values similar to
those found in sepsis)
– Hyponatremia (<130)
– Hyperglycemia
– Hyperkalemia
• Blood gas
– Metabolic acidosis
• Blood culture
• Fecal occult blood test
Initial work up for our
Radiology:
patient?
• STAT abd xray (our
patient)
– AP – pneumatosis
intestinalis, neg
football sign
– Cross table lateral –
no free air
– How often?
Example of football sign:
http://fn.bmj.com/content/88/1/F75.extra
ct
• Every 6-12 hours
• Abd ultrasound
Example of cross-table
lateral x-ray with free air
http://radiopaedia.org/articles/neonatalpneumoperitoneum
(another option)
– Gas bubbles in
hepatic parenchyma
– Pseudo-kidney signcentral echogenic
focus and
hypoechoic rim
– Limitations: user
dependant, not
always available
overnight.
Our patient’s x-ray: Pneumatosis Intestinalis
:http://www.nejm.org/doi/full/10.1056/NEJM200101113440205
Initial Management
Medical management (10-14 days)
• Make NPO, start on IVF
(consider TPN).
• Insertion of nasogastric tube to
suction for decompression
• Empiric antibiotics
– Ampicillin, gentamicin
– Clindamycin and/or flagyl are
often added for severe cases
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Cardiovasculatory/pulmonary
support as needed
Pediatric surgery consultation
Lab/radiologic monitoring:
– Q6-8 hours while patient
remains acutely ill
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Check urine output every 1-2
hours
– If low, give 10-20ml/kg/hr NS
Surgical management
• Absolute indication for
surgery
– Pneumoperitoneum
• Relative indication for surgery
– failure to improve
– progressive
thrombocytopenia
– Portal vein gas
– Severe peritonitis
• Surgical intervention
– Peritoneal drainage
– Laparotomy with resection of
affected bowel.
Prognosis
• With aggressive treatment and earlier diagnosis,
70-80% of infants survive.
• Infants requiring surgical intervention have a
higher mortality rate
• About half of survivors have no long-term
sequelae.
• Long term sequelae:
– Stunted growth
– Short gut syndrome / intestinal adhesions (in patients
requiring extensive resection.
– ELBW and infants with extreme prematurity may also
have developmental delay
References
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Abdullah, F., Y. Zhang, M. Camp, D. Mukherjee, and Et Al. "Necrotizing Enterocolitis in
20,822 Infants: Analysis of Medical and Surgical Treatments." Clinical Pediatrics 49.2
(2010): 166-71.
Farrugia, MK, AS Morgan, K. McHugh, and EM Kiely. "Neonatal Gastrointestinal
Perforation." Archives of Disease in Childhood. Fetal and Neonatal Edition 88.1
(2003).
Gordon, P. V., J. R. Swanson, J. T. Attridge, and R. Clark. "Emerging Trends in
Acquired Neonatal Intestinal Disease: Is It Time to Abandon Bell's Criteria?" Journal of
Perinatology 27.11 (2007): 661-71.
Gomella, Tricia Lacy., M. Douglas. Cunningham, and Fabien G. Eyal. "Necrotizing
Enterocolitis and Spontaneous Intestinal Perforation." Neonatology: Management,
Procedures, On-call Problems, Diseases, and Drugs. New York: McGraw-Hill Medical,
2009. 590-95.
Hallstrom, M., AM Koivisto, M. Janas, and O. Tammela. "Laboratory Parameters
Predictive of Developing Necrotizing Enterocolitis in Infants Born before 33 Weeks of
Gestation." Journal of Pediatric Surgery 41.4 (2006): 792-8.
Hoenig, Jeanette. "Necrotizing Enterocolitis." Pocket NICU. 2nd ed. Chicago, 2006.
95. Print.
Salama, Husam, and Orlando Da Silva. "Images in Clinical Medicine. Neonatal
Necrotizing Enterocolitis." New England Journal of Medicine 344.108 (2001).
Silva, CT, A. Daneman, OM Navarro, and Et Al. "Correlation of Sonographic Findings
and Outcome in Necrotizing Enterocolitis."Pediatric Radiology 37.3 (2007): 274-82.
Stoll, BJ. "Epidemiology of Necrotizing Enterocolitis." Clinical Perinatology 21.2
(1994): 205-18.
Wiswell, TE, CF Robertson, TA Jones, and DJ Tuttle. "Necrotizing Enterocolitis in Fullterm Infants. A Case Control Study."American J of Diseases of Children 142.5 (1988):
532-5.