Isolated basilar artery dissection associated with subarachnoid haemorrhage. traumatic or spontaneous?

Abstract

Intracranial vertebral dissection associated with subarachnoid haemorrhage is well recognised in forensic practice, basilar artery dissection does not feature in standard forensic textbooks. Although recognised in the neurosurgical and neurology literature, isolated basilar artery dissection (IBAD) is rare and is either traumatic or spontaneous. IBAD is usually fatal, however may have a good prognosis. In the majority of cases the basilar artery is involved by extension of a vertebral artery dissection. Clinically patients present with brainstem or cerebellar ischaemic strokes and less commonly with subarachnoid haemorrhage. There is a temporal relationship to unaccustomed neck movement or other trauma. IBAD should be considered at post-mortem examinations where widespread subarachnoid haemorrhage over the anterior brainstem and cerebellum is encountered where an aneurysm is not identified. The basilar artery is easily accessible at post-mortem allowing detailed serial examination of the vertebral and basilar arteries. Two of three cases were trauma related with skull fracturing in the region of the basilar artery dissection (fall and motor vehicle crash). The third case presented with headache and was spontaneous with no pre-existing vasculopathy. In all three cases, the basilar artery dissection was the cause of the death. Failure to recognise IBAD as an entity and confining examination only to the vertebral arteries may result in the source of the subarachnoid haemorrhage not being identified.