Pathophysiologic mechanisms of hydrocephalus.

Hydrocephalus is caused by a disequilibrium of forces at the ventricular-cerebral interface and may be progressive either due to a continued disequilibrium of forces or due to continued progressive periventricular ischemic injury. Treatment is indicated in all patients with progressive neurological deficit associated with progressive ventricular enlargement. Whenever possible, treatment should be directed toward the cause of the hydrocephalus (e.g., removal of tumors obstructing CSF flow) or the specifically abnormal force vector (e.g., shunting for increased intraventricular pulse waves due to an ectatic basilar artery). When it is not possible to treat the cause or the specifically abnormal force vector, treatment should be guided by the basic mechanisms--reduction of the intraventricular force (Fo), augmentation of the inward brain force (Fi), and improvement of nutrition and oxygenation of ischemic periventricular tissue.