Necrotizing Enterocolitis in Neonates

Since 1828, when preterm infants began being housed in specialized hospital units, necrotizing enterocolitis has been a common condition that is seen in almost all neonatal units around the world (Haque, 2016, p. 79).  In 1952, after reports of its pathological characterization, it was then given the name enterocolitis ulcerosa necroticans (Haque, 2016, p. 79).  In the 60’s, necrotizing enterocolitis was thought to be from postulated mesenteric hypoperfusion, rather than infection (Haque, 2016, p. 80).  Finally, by the 70’s, it was determined that necrotizing enterocolitis did not have just one cause (Haque, 2016, p. 80).  Multiple factors include immaturity of the preterm intestine, bowel ischemia, intestinal infection/infiltration, or formula/hyperosmolar feeding (Haque, 2016, p. 80).  

It was suggested that necrotizing enterocolitis had an infectious etiology by organisms such as Pseudomonas, Clostridium perfringens, several viral or infectious by nosocomial organisms, thus creating an epidemic (Haque, 2016, p. 79).  Necrotizing enterocolitis is one of the most common gastrointestinal risks in a preterm infant (Haque, 2016, p. 80).  The lower the gestational age the later the occurrence of necrotizing enterocolitis (Haque, 2016, p. 80).  Early presentation may suggest the diagnosis of spontaneous intestinal perforation with a peak occurrence at three weeks after birth in infants born before 32 weeks of gestation (Haque, 2016, p. 80).  Those born between 32 and 36 weeks symptoms occur 2 weeks after birth (Haque, 2016, p. 80).  After 36 weeks gestation, the symptoms may appear in under a week (Haque, 2016, p. 80).  Before diagnosing the pathogenesis of NEC, it is important to rule out the other conditions that also include similar symptoms of NEC, specifically in late preterm or term infants (Haque, 2016, p. 85).

If left untreated, death or the development of microcephaly with neurodevelopmental delays is the greatest risk for the infant (Haque, 2016, p. 79).  Other morbidities, such as cholestasis and short gut syndrome, may also occur (Haque, 2016, p. 79).  The cost of caring for infants with necrotizing enterocolitis is between 500 million and 1 billion dollars each year and the length of stay in the hospital is also increased by 20–60 days (Haque, 2016, p. 79).

Symptoms may occur because of prenatal stress, such as asphyxia at birth, intestinal anomalies, maternal substance abuse (cocaine), formula feeding, rapid advancement of feeds, or maternal chorioamnionitis (Haque, 2016, p. 80).  All of these conditions are triggered by mesenteric hypoxia and ischemia initiating the cascade of apoptosis leading to intestinal mucosal necrosis (Haque, 2016, p. 80).  Sepsis, if severe, may cause the development of an intestinal ileus with signs and symptoms including vomiting, abdominal distention, and the absence of bowel sounds (Haque, 2016, p. 81).  The final diagnosis is confirmed by an x-ray examination that shows multiple fluid levels with distended bowel loops but no evidence of pneumatosis or biliary gas (Haque, 2016, p. 81).  Another cause of enterocolitis is food‑protein induced enterocolitis syndrome in infants who have a cow’s milk intolerance (Haque, 2016, p. 81).  A cow’s milk allergy associated necrotizing enterocolitis is milder with low mortality rate (Haque, 2016, p. 81).  Another increased chance of an infant developing necrotizing enterocolitis is through cesarean sections where the opportunity for the baby to acquire colonization by friendly maternal vaginal commensal bacteria is lost (Haque, 2016, p. 83).

In early neonatal care, several factors can affect the intestinal flora in the gut of the newborn (Haque, 2016, p. 83).  One of those factors is the use of antibiotics soon after birth (Haque, 2016, p. 83).  Antibiotics reduce microbial diversity and the growth of good bacteria and thus increasing the risk of necrotizing enterocolitis (Haque, 2016, p. 83).  Evidence shows that reduced antibiotic exposure or duration decreases the risk of necrotizing enterocolitis (Haque, 2016, p. 83).  A recent study showed a reduction in the rate of NEC in two centers who changed to using piperacillin and tazobactam from ampicillin and gentamicin as their first‑line of antibiotic treatment (Haque, 2016, p. 83).  Once diagnosed, the treatment is total avoidance of both cow’s milk and breast milk (Haque, 2016, p. 81).  Based on the principle of bowel rest, this treatment has not changed over the last three decades (Haque, 2016, p. 86).  Additional treatments include gastric decompression by placing an oral gastric tube and antibiotics are given for possible infective etiology (Haque, 2016, p. 86).

The occurrence of necrotizing enterocolitis has increase in countries where smaller and smaller babies of lower and lower gestation are surviving over the last few decades (Haque, 2016, p. 80).  Other countries have seen a decrease in necrotizing enterocolitis (Haque, 2016, p. 80).  Previous studies have suggested that there are no geographical, seasonal, or racial differences in the rate of necrotizing enterocolitis (Haque, 2016, p. 80).  However, more recent studies have challenged this view showing evidence that Afro‑American neonates have a higher incidence of necrotizing enterocolitis than Caucasian equivalents (Haque, 2016, p. 80).  Also, the chance of necrotizing enterocolitis and is slightly higher during the winter months (Haque, 2016, p. 80).  Japan, Switzerland, Italy, and Austria has reported a lower frequency of necrotizing enterocolitis, but higher frequency of the disease is reported from Ireland, UK, USA, and Canada (Haque, 2016, p. 80).  Unfortunately, strong data from developing countries is not available to give comparative figures so it is unclear whether these differences are due to care strategies, environment, climate, ethnic background, or genetics (Haque, 2016, p. 80).  An uncommon condition more likely to be seen in Asian and African infants is food‑protein induced enterocolitis syndrome because they are more prone to have cow’s milk (Haque, 2016, p. 81).  Continued research is needed and a review will need to be updated every now and then (Haque, 2016, p. 80).

To help find a suitable article for the literature review I used WGU’s library.  In the first field I typed, “necrotizing enterocolitis” and in the second field I typed, “diagnosing”.  I also changed the publication date to 2013 to narrow down the search results.  The search results yielded over one thousand articles consisting of academic journals, books, and reviews.

...