Neonatal necrotizing enterocolitis: 1. Clinical aspects

Risk factors for necrotising enterocolitis: the influence of gestational age

Over a 7 year study period, 82 infants were identified who had necrotising enterocolitis (NEC). A case-control study of the 74 preterm infants was performed to determine those factors which contributed to the development of NEC. The 35 infants with NEC and gestation between 30-36 weeks, when compared with control infants matched for gestational age, had significantly lower birthweight centiles, cord pH, and 1 minute Apgar scores. By contrast, there were no significant differences between the 39 infants with NEC and controls in the 25-29 week group, except that fewer babies with NEC had received breast milk. The eight term babies all appeared to have an obvious predisposing event. We thus propose a model in which susceptibility to NEC is dependent on gestational age. In the 25-29 week range all babies are at risk on the basis of extreme prematurity. In the 30-36 week range asphyxiated and growth retarded babies are at increased risk, while at term a major predisposing event appears to be required.

Outcome of neonatal necrotising enterocolitis: results of the BAPM/CDSC surveillance study, 1981-84

Neonatologists in 100 special care baby units in the United Kingdom and Ireland collaborated in a four year surveillance study of neonatal necrotising enterocolitis. The average overall annual reporting rate of necrotising enterocolitis for infants in England and Wales was 0.3/1000 live births, but ranged from 9.5/1000 live births in infants weighing less than 1000 g at birth to 0.2/1000 live births in infants weighing 2500 g or more. There were more deaths among girls, infants who weighed less than 1500 g at birth, those whose bleeding was abnormal or who had low peripheral platelet counts, infants with Gram negative bacteraemia, and very low birthweight infants who developed it during the first few days of life. In both boys and girls, and in all birthweight groups, operation was associated with increased mortality.

A case control study of necrotizing enterocolitis occurring over 8 years in a neonatal intensive care unit

The perinatal histories of 27 newborn infants with NEC were compared to those of 54 infants of equivalent birth weight who did not have NEC during an 8-year study period to see if possible predisposing factors were independent of the confounding effect of birth weight. No differences were observed in gestational age, degree of intrauterine growth retardation, premature rupture of membranes, perinatal asphyxia, skin temperature at admission, haematocrit, presence or absence of respiratory distress syndrome, umbilical catheter placement, start and type of feeding or presence of positive blood cultures. Prematurity is the greatest risk factor predisposing to the development of NEC and the perinatal problems which precede the onset of NEC are common among all premature infants.

Perinatal risk factors for necrotizing enterocolitis

The perinatal histories of 50 very low birthweight infants weighing 1500 g, or less, with necrotizing enterocolitis were compared with those of the remaining 325 very low birthweight infants who were admitted to this hospital during a four year study period. Many factors previously reported to be associated with necrotizing enterocolitis were found with equal frequency in both groups of babies. The only adverse factor which was more frequently present in patients with necrotizing enterocolitis was hypothermia on admission to hospital. Those infants who developed severe necrotizing enterocolitis also had a higher incidence of polycythaemia. A further controlled study which examined feeding practices showed that the timing, type, and volume of milk feeding were not different in infants with necrotizing enterocolitis and matched controls. Prematurity is clearly the greatest risk factor which predisposes to the development of necrotizing enterocolitis and most of the factors previously implicated in the aetiology may simply represent the descriptive characteristics of a population of sick, very low birthweight infants.

Necrotizing enterocolitis in very low birthweight infants: a four-year experience

Fifty (13%) of 375 infants who weighed 1500 g or less at birth had necrotizing enterocolitis (NEC). Haematological changes suggestive of sepsis occurred in 83% and positive bacteriological cultures were found in 38%, the most common organism isolated being Clostridium perfringens. Complications included intestinal perforation in six patients and recurrence of NEC in five, of whom one subsequently developed an intestinal stricture. Five of the eight nursery deaths were secondary to peritonitis and overwhelming sepsis from NEC. In spite of the discontinuation of milk feeds for prolonged periods, satisfactory caloric intake and weight gain were achieved with parenteral nutrition in the survivors. Of the 41 long-term survivors, six (15%) were found to have a disability at 2 years of age, corrected for prematurity, compared with 48 (20%) of 241 very low birthweight survivors from the same study period who did not have NEC. None had evidence of gastrointestinal dysfunction. Six (15%) children remained below the 10th percentile for both weight and height. This study showed that early diagnosis and therapy for NEC in very low birthweight infants were associated with a favourable short- and long-term outcome.

Pneumatosis oculi and spontaneous hyphema in association with pneumatosis intestinalis

A premature infant with acute necrotizing enterocolitis, Escherichia coli sepsis, and disseminated intravascular coagulation developed spontaneous bilateral hyphemas at 3 days of age. The necrotizing enterocolitis was associated with gas bubbles in the intestinal walls. The anterior chambers of both eyes also contained bubbles of gas, formed possibly by a mechanism similar to those in the intestine.