Risk factors and ultrasonographic profile of posterior fossa haemorrhages in preterm infants

Aims: While preterm infants are known to be at risk of intracranial haemorrhages, advances in ultrasound imaging of preterm babies have facilitated recognition of presence of haemorrhages in the posterior fossa, which include cerebellar and Cisterna Magna haemorrhages. There are limited data on the profile and predisposing risk factors. The objective was to identify antenatal, intrapartum and post-natal risk factors for and to define the clinical spectrum. The study was designed as a retrospective case-control study in the setting of a tertiary level neonatal intensive care unit. Preterm babies ≤30 weeks gestation age admitted between January 2005 and December 2006, with an ultrasound diagnosis of posterior fossa haemorrhage and an equal number of controls matched for gestation age, gender and month of birth with normal cranial scans were selected. Systematic chart and radiographic review was done. All cranial ultrasounds in both groups were reviewed. Results: Eighteen babies had documented posterior fossa haemorrhage (13 cerebellar, 5 isolated Cisterna Magna, 10 both), the median time of detection being 2.5 days. Eleven babies had either no or grade I/II supratentorial bleeds, while half of all cerebellar bleeds were bilateral. All haemorrhages were visualised from mastoid view and none from anterior fontanel. On univariate analysis, multiple gestations, lack of antenatal steroids, foetal heart rate abnormalities, need for volume expanders and cardiotrophins and sepsis were associated with a higher risk for having posterior fossa bleeds. Conclusions: Posterior fossa haemorrhages in preterm babies are being increasingly recognised. Antenatal, intrapartum and post-natal factors may predispose towards haemorrhages in the cerebellum or Cisterna Magna.