Koletzko B, Poindexter B, Uauy R (eds): Nutritional Care of Preterm Infants: Scientific Basis and Practical Guidelines. World Rev Nutr Diet. Basel, Karger, 2014, vol 110, pp 253–263 (DOI: 10.1159/000358474)
Necrotizing Enterocolitis Josef Neu Department of Pediatrics/Neonatology, University of Florida, Gainesville, Fla., USA Reviewed by Nicholas B. Embleton, Neonatal Service, Newcastle Hospitals, Institute of Health and Society, Newcastle University, Newcastle upon Tyne, UK; Brenda Poindexter, Riley Hospital for Children at Indiana University Health, Indianapolis, Ind., USA
Abstract Necrotizing enterocolitis (NEC) is the most common severe neonatal gastrointestinal emergency that predominantly affects premature infants. Its morbidity and mortality is similar to other severe childhood diseases such as meningitis and leukemia, and is becoming increasingly recognized as a major cause of neurodevelopmental delays. The etiology of NEC remains obscure despite over 40 years of research, partly because it is more than one disease and databases including NEC have been diluted by these different entities. Furthermore, good animal models that represent the most classic form of the disease seen in preterm human infants are lacking. This chapter provides an overview of the pathophysiology, © 2014 S. Karger AG, Basel diagnosis, treatment and prevention of what has been termed ‘NEC’.
Necrotizing enterocolitis (NEC) is the most common severe neonatal gastrointestinal emergency that predominantly affects premature infants. The mortality of NEC ranges between 20 and 30%, with the greatest mortality among those requiring surgery [1]. What is termed ‘NEC’ is likely to be more than one entity. Although the final outcome in NEC is necrosis of the bowel, different cases are preceded by different triggering events and pathophysiologic mechanisms, which is one of the factors that makes this such an elusive disease to diagnose, prevent and manage. In this chapter, the author will review some of the current ideas about pathogenesis of the most common form of NEC seen in preterm infants, discuss diagnosis, current treatment modalities, and preventative strategies.
While it is well known that NEC primarily affects premature infants, 7–15% of NEC cases occur in term or late preterm infants [2, 3]. In term infants, bowel necrosis is commonly associated with congenital heart diseases, such as hypoplastic left heart syn-
Downloaded by: UCLA Biomedical Library 128.97.90.221 - 4/30/2014 12:16:37 PM
Pathogenesis
Microbial dysbiosis
Genetic predisposition
Intestinal immaturity
Fig. 1. Genetic predisposition, intestinal immaturities and microbial dysbiosis combine to induce NEC.
NEC
Intestinal Immaturity Immature motility, digestion, absorption, immune defenses, barrier function, and circulatory regulation predispose the preterm infant to an increased risk of intestinal injury [15]. Certain interventions may exacerbate the preexisting immaturities. For example, since gastric acid secretion is not yet fully developed and relatively low in the
254
Neu Koletzko B, Poindexter B, Uauy R (eds): Nutritional Care of Preterm Infants: Scientific Basis and Practical Guidelines. World Rev Nutr Diet. Basel, Karger, 2014, vol 110, pp 253–263 (DOI: 10.1159/000358474)
Downloaded by: UCLA Biomedical Library 128.97.90.221 - 4/30/2014 12:16:37 PM
drome and coarctation of the aorta, which result in intestinal ischemic necrosis [4, 5]. NEC has also been associated with other anomalies, including aganglionosis [6] and gastroschisis [7]. Most of the cases of NEC in term infants present within the first few days after birth. More than 85% of all NEC cases occur in very low birth weight premature infants (
Necrotizing Enterocolitis Josef Neu Department of Pediatrics/Neonatology, University of Florida, Gainesville, Fla., USA Reviewed by Nicholas B. Embleton, Neonatal Service, Newcastle Hospitals, Institute of Health and Society, Newcastle University, Newcastle upon Tyne, UK; Brenda Poindexter, Riley Hospital for Children at Indiana University Health, Indianapolis, Ind., USA
Abstract Necrotizing enterocolitis (NEC) is the most common severe neonatal gastrointestinal emergency that predominantly affects premature infants. Its morbidity and mortality is similar to other severe childhood diseases such as meningitis and leukemia, and is becoming increasingly recognized as a major cause of neurodevelopmental delays. The etiology of NEC remains obscure despite over 40 years of research, partly because it is more than one disease and databases including NEC have been diluted by these different entities. Furthermore, good animal models that represent the most classic form of the disease seen in preterm human infants are lacking. This chapter provides an overview of the pathophysiology, © 2014 S. Karger AG, Basel diagnosis, treatment and prevention of what has been termed ‘NEC’.
Necrotizing enterocolitis (NEC) is the most common severe neonatal gastrointestinal emergency that predominantly affects premature infants. The mortality of NEC ranges between 20 and 30%, with the greatest mortality among those requiring surgery [1]. What is termed ‘NEC’ is likely to be more than one entity. Although the final outcome in NEC is necrosis of the bowel, different cases are preceded by different triggering events and pathophysiologic mechanisms, which is one of the factors that makes this such an elusive disease to diagnose, prevent and manage. In this chapter, the author will review some of the current ideas about pathogenesis of the most common form of NEC seen in preterm infants, discuss diagnosis, current treatment modalities, and preventative strategies.
While it is well known that NEC primarily affects premature infants, 7–15% of NEC cases occur in term or late preterm infants [2, 3]. In term infants, bowel necrosis is commonly associated with congenital heart diseases, such as hypoplastic left heart syn-
Downloaded by: UCLA Biomedical Library 128.97.90.221 - 4/30/2014 12:16:37 PM
Pathogenesis
Microbial dysbiosis
Genetic predisposition
Intestinal immaturity
Fig. 1. Genetic predisposition, intestinal immaturities and microbial dysbiosis combine to induce NEC.
NEC
Intestinal Immaturity Immature motility, digestion, absorption, immune defenses, barrier function, and circulatory regulation predispose the preterm infant to an increased risk of intestinal injury [15]. Certain interventions may exacerbate the preexisting immaturities. For example, since gastric acid secretion is not yet fully developed and relatively low in the
254
Neu Koletzko B, Poindexter B, Uauy R (eds): Nutritional Care of Preterm Infants: Scientific Basis and Practical Guidelines. World Rev Nutr Diet. Basel, Karger, 2014, vol 110, pp 253–263 (DOI: 10.1159/000358474)
Downloaded by: UCLA Biomedical Library 128.97.90.221 - 4/30/2014 12:16:37 PM
drome and coarctation of the aorta, which result in intestinal ischemic necrosis [4, 5]. NEC has also been associated with other anomalies, including aganglionosis [6] and gastroschisis [7]. Most of the cases of NEC in term infants present within the first few days after birth. More than 85% of all NEC cases occur in very low birth weight premature infants (
