Hepatitis C is a single stranded RNA virus leading to hepatic fibrosis, cirrhosis and occasionally hepatocellular carcinoma.
Unlike Hepatitis B, vertical transmission is rare (~5% in Hep C viraemic mothers, increasing to 15-25% from a mother co-infected with HIV), so only high-risk women are screened.
Reference: Prasad, M. R., & Honegger, J. R. (2013). Hepatitis C virus in pregnancy. American journal of perinatology, 30(2).
The CRIB (Clinical Risk Index for Babies) score, and its update, CRIB II, were designed to predict mortality for infants born below 32/40.
They were based on specific criteria present in the first 12 hours of the infant’s life (to minimise treatment influences). For CRIB II, they are:
- Birth weight by gestation
- Maximum base deficit in the first 12h
- Admission temperature
Though there is some correlation between the score and mortality, its use to predict neurological impairment is not strong and it is no longer used routinely.
Reference: Dorling JS, Field DJ, Manktelow B. ‘Review – Neonatal disease severity scoring systems’ Arch Dis Child Fetal Neonatal Ed. 2005; 90:F11-F16.
Giving supplemental oxygen in preterm infants with incompletely vascularised retina causes hyperoxia and vasoconstriction. This in turn may lead to local hypoxia, up‐regulation of vascular endothelial growth factor, and excessive proliferation of new vessels and fibrous tissue that invades the vitreous. Contraction of fibrous tissue can result in retinal detachment.
Reference: Tin et al, Optimum Oxygen Therapy in Preterm Infants, Arch Dis Child Fetal Neonatal Ed. Mar 2007; 92(2): F143–F147
Meconium ileus is due to obstruction of the terminal ileum with thick, viscid meconium.
It has an incidence of 1: 1,000 – 2,000 live births.
80 – 90% of neonates with meconium ileus will have cystic fibrosis (usually the first presentation), but only 15% of children with cystic fibrosis present with meconium ileus.
Reference: McHoney M, McNamara V, Wheeler R. ‘Surgery’ In: Beattie M, Champion M, editors. Essential Revision Notes in Paediatrics for the MRCPCH. 2nd ed. Pastest. (2006) Chapter 24, pg 946.
Hydrocortisone is effective in increasing blood pressure, with few other acute side-effects in the sick preterm infant. However, benefit data and long-term safety data are unknown.
It is likely that it works by improving the immature neonatal stress response (due to relative adrenal insufficiency) and by increasing the number of receptors sites for inotropes.
Reference: Ibrahim H, Sinha IP, Subhedar NV. Corticosteroids for treating hypotension in preterm infants. Cochrane Database of Systematic Reviews 2011, Issue 12. Art. No.: CD003662. DOI: 10.1002/14651858.CD003662.pub4.
Also see Neonatal Tip 140.
Other risk factors for NEC include:
- Hypoxic insult – especially in the more mature infant with NEC
- Anaemia / need for transfusion
- Use of non-human milk or hyperosmolar feeds (e.g. fortifier additives)
- Rapid introduction and escalation of enteral feeds
- Patent ductus arteriosus
- Prolonged use of antibiotics
Fox TP, Godavitarne C. ‘What Really Causes Necrotising Enterocolitis?’ ISRN Gastroenterology, vol. 2012, Article ID 628317, 9 pages, 2012. doi:10.5402/2012/628317
J. Rennie, Roberton’s Textbook of Neonatology, Elsevier, Beijing, China, 4th edition, 2005.