Necrotizing enterocolitis in preterm infants with poor outcome: causes, risk factors for mortality, histological changes of the intestinal lining

Abstract

Despite advances in the diagnosis and treatment of necrotizing enterocolitis (NEC), the associated morbidity and mortality rates remain high.

Purpose - to establish risk factors for mortality of necrotizing enterocolitis in preterm born infants, as well as to analyze histological changes of the intestinal lining.

Materials and methods. The course of NEC in 21 preterm neonates who died of this disease (group 1, n=21) over a period of 3 years was analyzed. To establish risk factors for mortality rate health indicators of children in group 1 were compared with the course of NEC in children who survived with similar stages of the disease (group 2, n=43). The following research methods were used: general clinical, laboratory, instrumental, histological and statistical.

Results. Our data show that the main causes of severe stages of NEC in preterm infants is infection, often in combination with severe asphyxia.

The identified risk factors for mortality allowed to establish that the risk of death for children with NEC was associated with: male sex (OR=4.675; χ²=7.679; p=0.006) - increases the risk for mortality by 4 time; inflammatory changes in the placenta (OR=6.139; χ²=10.501; p=0.002) - increases the risk by 6 times; red blood cell transfusion in children (OR=8.262; χ²=8.557; p=0.004) - increases the risk by 8 times;  thrombocytopenia (OR=4.320; χ²=4.866; p=0.028) - increases the risk by 4 time; the developmen of multiple organ system failure (OR=12.364; χ²=17.578; p<0.001) and DIC syndrome (OR=10.725; χ²=14.592; p<0.001) - increases the risk by 12 and 11 times, respectively; the positive symptoms - oedema of the anterior abdominal wall (OR=14.025; χ²=19.258; p<0.001) and vasodilation of the anterior abdominal l wall (OR=5.333; χ²=5.444; p=0.02) - increases the risk by 14 and 5 times, respectively; the intestinal pneumatosis on abdominal when x-ray detected (OR=6.840; χ²=6.867; p=0.009) and the peritoneal effusion detected by abdominal ultrasound (OR=8.750; χ²=14.448; p<0.001) - increases the risk of mortality by 7 and 9 times, respectively.

During histological examination of the intestinal wall with NEC lymphohistiocytic infiltration of submucosa indicates perinatal hypoxia and its crucial role in the thanatogenesis of the disease, while polymorphonuclear segmental neutrophil infiltration is associated with perinatal infection. In 15 children (71.4%) changes of both types were noted, which indicates mixed etiology of intestinal lesions.

Conclusions. Study results confirmed that necrotizing enterocolitis is a serious disease of newborns with a high mortality rate. The severe forms of NEC occur against the background of infection in combination with hypoxia. The obtained risk factors for the mortality rate of NEC allow to improve the prognosis of the course of this disease, will provide an opportunity to identify children who need increased attention of doctors to the treatment and further management of these patients with the use of preventive technologies that can prevent catastrophic consequences. The presence of congenital intestinal defects in combination with premature birth contribute to the development and aggravate the course of NEC, up to the development of stage III and a negative prognosis of the disease.

The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local ethics committee of all participating institutions. The informed consent of the parents of patient was obtained for conducting the studies.

No conflict of interests was declared by the authors.