Preterm delivered at 36+5 weeks with severe symmetrical IUGR – birth weight of 1.9 kg (<3rd centile). He was delivered via NVD with good Apgar score of 9-9. He was on gradual escalation of formula feeds with full feeds achieved on day 7 of life. On day 9 of life, while in Nursery, he developed acute respiratory distress with poor perfusion with an episode of bloody stools.
Necrotizing enterocolitis is a disease of prematurity, with only 10% occurring in full-term infants. It usually presents in the 1st – 2nd week of life in preterm infants, while usually presenting within the first 5 days in full-term infants . In the very premature infant, it may develop later in the 2nd – 3rd week of life.
It is important to recognise the normal bowel gas pattern in an infant, which is often described as a “mosaic” appearance (See day 8 radiograph: normal mosaic pattern over the left abdomen). Loss of this pattern with rounding and elongation of the loops must be considered an early warning sign, particularly in the right clinical setting (See day 8 radiograph: rounded dilated loop over the right abdomen). This represents ileus. It is the earliest, the most common (90%) and possibly the only sign of NEC. Intramural gas can also precede clinical deterioration. It is predominantly hydrogen that is produced by intestinal bacteria (most commonly Klebsiella ) acting on milk formula in the intestinal lumen. Mucosal injury then allows gas and bacteria to enter the intestinal wall.
Portal venous gas is a late radiographic feature (See day 9 radiograph) and has been cited as the worst prognostic radiographic abnormality, associated with 65-71% mortality [3,4]. However, also keep in mind that the commonest cause of portal venous gas in neonates is still gas tracking from an umbilical venous catheter. Last but not least, any signs of perforation must be actively searched for as it then pushes the patient towards surgical treatment. If in doubt, a decubitus radiograph or early repeat imaging is recommended.
Remember that radiographic findings can precede clinical deterioration. Keeping in mind the infant’s maturity, day-of-life and feeding status, a radiologist may be the first to diagnose NEC and its complications.
- Ostlie, Daniel J., et al. “Necrotizing enterocolitis in full-term infants.” Journal of pediatric surgery 38.7 (2003): 1039-1042.
- Bell MJ, Shackelford P, Feigin RO, Temberg JL, Brotherton T. Epidemiologic and bacteriological evaluation of neonatal necrotizing enterocolitis. J Pediatr Surg 1979;14:1-4
- Kosloske, Ann M., et al. “Necrotizing enterocolitis: value of radiographic findings to predict outcome.” American Journal of Roentgenology 151.4 (1988): 771-774
- Cikrit 0, Mastandrea J, Grosfeld JL, West KW, Schreiner RL. Significance of portal vein air in necrotizing enterocolitis: analysis of 53 cases. J Pediatr Surg 1985;20:425-430
- Epelman, Monica, et al. “Necrotizing Enterocolitis: Review of State-of-the-Art Imaging Findings with Pathologic Correlation 1.” Radiographics 27.2 (2007): 285-305.