Unexpected natural death of cerebral origin in medicolegal practice.

Due to the rapid evolution of vascular lesions it is not surprising that most causes of sudden death of cerebral origin are due to vascular pathology. Of the traumatic causes extradural haemorrhage is a fairly common clinical entity but as a cause of death declining in its frequency. Sources of diagnostic error can be attributed to the fact that not all patients with extradural haematomas have marked external evidence of trauma and a significant number, particularly children and adolescents, show no radiological, clinical or for that matter, post-mortem evidence of a fracture. Subdural haematomas of a chronic variety are usually produced by minor trauma and occur predominantly in the older person. Acute subdural haematomas are most frequently the result of trauma and may be rapidly fatal due to the associated massive cerebral damage. That intracranial aneurysm or angioma may rupture into the subdural space and cause an acute or chronic subdural haematoma, is less widely appreciated. The acute spontaneous arterial subdural haematoma due to the rupture of a cortical vessel, usually one affected by atheroma, into the subdural space is an uncommon entity. It should be looked for specifically in patients with minimal trauma and the clinical picture of an acute subdural haematoma. Subarachnoid haemorrhage due to aneurysmal rupture is still the common cause of unexpected rapid demise in young adults. There is very little evidence that antecedent trauma or exertion play a part as precipitating factors. Centrally placed aneurysms situated at the anterior communicating artery origin or terminal carotid seem to be particularly malignant in their effects. Cause of death is usually massive extrusion of blood into the intracranial cavity with increasing intracranial pressure, compressive haematoma formation and widespread arterial spasm with ischaemic consequences. Whether aneurysmal rupture can be caused by trauma cannot really be satisfactorily resolved. Intracerebral haemorrhage is most commonly due to hypertension but, as in the case of other haematomas, bleeding disorders may also be a cause. Intracerebral haematoma may, however, also result from rupture of micro-angiomata and the brain should be carefully examined for them in the young patient without evidence of hypertension. Hypertensive crises occurring in people on monoamine oxidase inhibitors should also be remembered as a cause of intracerebral haemorrhage.