External hydrocephalus as a cause of infant subdural haematoma; epidemiological and radiological investigations of infants suspected of being abused.

Abstract Background Acute and chronic subdural haematomas (ASDH/CSDH) in infants have been regarded as highly specific for abuse. Other causes of CSDH have not been investigated in a large population. Purpose To investigate to what extent external hydrocephalus is present in infants with ASDH and CSDH undergoing evaluation for abuse. Material and methods Eighty-five infants suspected of being abused, with ASDH (n=16) or CSDH (n=69), were reviewed regarding age, risk factor profiles, cranio-cortical width (CCW), sino-cortical width (SCW), frontal interhemispheric width (IHW), subarachnoid space width (SSW) and head circumference (HC). In infants with unilateral SDH, correlations between contralateral SSW and ipsilateral CCW and SDH width were investigated. Results Infants with CSDH had significantly lower mortality, were more often premature and male and had significantly higher CCW, SCW, IHW and SSW than infants with ASDH (p 5 mm, in addition to increased HC. Conclusion A substantial proportion of infants with CSDH who had been suspected of being abused had findings suggesting external hydrocephalus.