Background Perinatal infratentorial haemorrhage (PIH) is a rare birth complication associated with abnormal labour.

Case presentation A baby boy was born by vacuum extraction at 41 weeks’ gestational age. The pregnancy was uneventful and Apgar scores were 3/6/9. Following initial resuscitation, insufficient and irregular breathing, non-reactive pupils and absence of spontaneous movements were noted. A diagnosis of perinatal asphyxia with hypoxic–ischaemic encephalopathy (HIE) was considered. Therapeutic hypothermia (TH) for 72 hours was initiated. Cerebral ultrasound showed only a mildly hyperechogenic periventricular substance. A brain MRI on the fourth day of life revealed a subdural haemorrhage in the posterior fossa with compression of the fourth ventricle.

Conclusion PIH is an important differential diagnosis to HIE that can be missed with ultrasound. PIH is a treatable condition but may be aggravated by TH. Therefore, in neonates at risk for PIH, a more detailed ultrasound protocol or brain MRI should be considered early.