Necrotizing Enterocolitis or “NEC” is a life-threatening type of intestinal infection that can occur in newborn babies. NEC primarily occurs in premature babies who are formula-fed, with over 90% of all cases occurring in babies born before 37 weeks gestation. On this page, our lawyers will explain the clinical characteristics of NEC and look at the causes, diagnosis, treatment, and outlook for the condition.What is NEC?
Necrotizing enterocolitis (NEC) is an extremely dangerous neonatal infectious disease that claims the lives of hundreds of newborn babies every year. NEC is a very aggressive type of gastrointestinal bacterial infection that primarily occurs in premature babies. The infection originates in the infant’s upper and/or lower intestine which triggers acute inflammation of the intestinal wall tissue. This bacteria infection rapidly invades the inner walls of the intestine and begins eating away through the full thickness of the intestinal wall tissue.
As the NEC bacterial infection attacks the intestinal walls, it causes major cellular damage and death resulting in creeping necrosis (tissue death). If NEC is allowed to progress, the rapid tissue decay will eventually cause a perforation or hole to form in the intestine. Once this occurs, contents of the intestine will spill into the abdominal space causing peritonitis.
Once NEC advances to the stage where an intestinal perforation occurs it becomes very deadly. Bacteria normally contained within the gastrointestinal system invade the body leading to systemic infection and eventually sepsis.NEC Occurrence Rate
Incidence rates for NEC in all babies, both full-term and premature, are extremely low. NEC is diagnosed in approximately 2-3 out of every 1,000 live births worldwide (0.003%). Occurrence rates vary significantly by location and are generally higher in developed countries with more premature births.
If we look at NEC statistics for babies born prematurely (<37 weeks) the picture is much different. NEC occurs in approximately 5% of all premature babies and it accounts for 1 out every 10 NICU admissions. For babies with a birth weight under 1500 grams (3.3 lbs.), the NEC incidence rate jumps to around 10%. The occurrence rate for NEC in premature infants increases, even more, when the baby is fed with cow-milk formulas such as Similac or Enfamil. Research has shown that preemies who are formula-fed are 10 times more likely to be diagnosed with NEC compared to those fed with breast milk.NEC Mortality Rate
NEC is a dangerous and potentially lethal medical condition, especially for premature infants with low birth weight. Systemic infections resulting from NEC are one of the leading causes of death in newborns. The mortality rate for NEC varies depending on several factors including the stage at which the condition is diagnosed and the gestational age and birth weight of the baby.
The overall mortality rate for NEC is around 25%. The mortality rate for NEC increases dramatically, however, for very premature and underdeveloped infants. For babies with a birth weight under 1500 grams (3.3 lbs.), the NEC mortality rate jumps to around 50%. For infants weighing less than 1000 grams (2.2 lbs.), NEC can be a death sentence with a mortality rate close to 100%.Diagnosing NEC
Early diagnosis of NEC in infants is extremely difficult because, in its earliest stages, the symptoms of NEC are very subtle and often imperceptible. Even when NEC starts to progress to more advanced stages, the clinical symptoms tend to mimic the symptoms of much more common and benign neonatal conditions such as feeding intolerance.
Initial physical symptoms of NEC usually start with the baby not being able to tolerate feedings. This is generally accompanied by abdominal bloating (distention) and sometimes vomiting of green bile. When the NEC infection has invaded the wall of the colon it may cause blood to appear in the baby’s stool.
When NEC progresses to a more advanced stage it often triggers additional symptoms such as respiratory difficulties and abnormally low heart rate. Low blood pressure and abdominal tenderness are also signs of advanced-stage NEC.
When NEC is suspected, doctors will order lab work and an abdominal x-ray. The initial diagnosis of NEC is usually first confirmed by the identification of small gas or air bubbles in the intestinal walls on the x-ray. Low platelet levels in the blood work are also an indication of NEC.Treatment for NEC
Once NEC is diagnosed immediate medical treatment is critical. Treatment for NEC begins with emergency non-surgical interventions. All feedings of the baby are immediately stopped, and the intestines are decompressed using a suction tube. Parenteral fluids are administered to facilitate circulation and make up for the fluid loss caused by the infection.
Meanwhile, the infant is immediately started on a very strong course of systemic antibiotics. These usually include a combination of a beta-lactam antibiotic and an aminoglycoside. The antibiotics are continued for at least 2 weeks.
For severe, late-stage cases of NEC (where intestinal perforation has occurred) emergency surgical intervention will be necessary. If there are indications of intestinal perforation or peritonitis, surgery will be performed immediately to assess the extent of necrosis and remove dead intestinal tissue.
Surgical treatment for NEC involves the removal of sections of the intestines and bowel which are no longer viable due to necrosis. This can have long-term health effects so surgeons are generally careful to leave as much tissue as possible.Causes of Necrotizing Enterocolitis (NEC)
The exact cause of NEC is not fully understood, but the condition is generally known to be related to underdevelopment in the gastrointestinal system of infants. When the baby’s gastrointestinal system is not fully developed, it is not able to contain certain dangerous types of bacteria as it does in adults.
This is why premature infants are much more susceptible to NEC compared to full-term babies with more fully developed digestive tracts.Infant Formula Increases the Risk of NEC in Preemies
Current scientific research has established that infant formulas made from cow’s milk greatly increase the occurrence rate of NEC in premature babies. The evidence suggesting a positive association between infant formulas and NEC in preemies dates back to the early 1990s, but in recent years this connection has become widely accepted in the medical community.
One of the most prominent clinical studies on the subject was published in 2010 in the Journal of Pediatrics. It compared the occurrence rates of NEC in formula-fed infants to those fed exclusively with breast milk. The study found feeding only human breast milk to premature infants resulted in a 90% reduction in the incidence rate of NEC. This was soon followed by a report from the U.S. Surgeon General in 2011 which stated that formula-fed preemies were 14 times more likely to be diagnosed with NEC compared to breast-fed preemies.
In 2017, the results of 3 separate studies were published on the subject. All of the studies reported similar findings showing that premature infants who were fed with bovine milk-based formulas displayed dramatically higher rates of NEC.