The acute reversal sign: comparison of medical and non-accidental injury patients.

OBJECTIVES: (1) To compare the intracranial computed tomography (CT) appearances of patients admitted with various causes of hypoxic ischaemic encephalopathy. Children with known documented accidental trauma were excluded. (2) To compare our results with those in the published literature.
MATERIALS AND METHODS: Seventy-three patients aged between 1 day and 15 years were admitted with clinical features of brain injury and underwent cranial CT. A retrospective review of their medical records and radiology was undertaken. Clinical and radiological data were collected.
RESULTS: On the basis of the combination of the presenting clinical history, progress, outcome, long term follow up and radiology, two groups of patients were identified. Forty-seven children had been the victims of non-accidental injury (NAI). No child in this group had any associated medical condition or any other medical cause for brain injury. All 47 children demonstrated hypoxic ischaemic encephalopathy and had CT signs of cerebral oedema and 'Reversal Sign'. Intracranial haemorrhage was a highly associated feature. Subdural blood was demonstrated in all 47, acute interhemispheric fissure subdural in 42, intracerebral blood in 16 and intraventricular blood in nine. The remaining 26 children were found to have an identifiable 'medical' cause for brain injury. Acute reversal was demonstrated in 21 of this group. Intracranial haemorrhage was uncommon, found in only five and all five had an underlying predisposition to bleeding. No patient in this group demonstrated subdural blood.
CONCLUSION: Non-accidental injury is strongly associated with the finding on CT of intracranial blood, particularly subdural haematoma and interhemispheric fissure bleeding in the presence of hypoxic ischaemic brain injury. The outlook is extremely poor whatever the underlying cause for hypoxic ischaemic brain injury.