Plasticity of the brain in respect of functional restoration after subarachnoid haemorrhage.

Subarachnoid haemorrhage caused by aneurysmal rupture constitutes a great impact on the brain and on the intracranial content as a whole, with emphasis on the subarachnoid spaces and arteries. The rupture is followed by a wide range of pathological alterations in the neural function and an outcome varying from neglected signs subsiding in a few days to immediate death. Two main factors seem to influence the different events after subarachnoid bleeding. One is the rupture itself which can be extremely variable in severity and in its immediate as well as late consequences. The other is the ability of all parts of the intracranial content to recover. In order to understand either of both the other should also be looked at and both have to be dealt with if we are to treat patients with an aneurysmal rupture properly. For this reason a grading of rupture will be given in respect of some characteristic events in the light of neural restoration. Clearing of CSF, resolution of brain oedema, restoration of impaired CBF, absorption of cisternal and parenchymal haematoma are all of importance. The majority of lesions which developed after the rupture are not fatal or irreversible and even the neural tissue destroyed by the impact or late ischaemia can be functionally replaced. Possible methods of treatment for attaining this functional restoration will be discussed.