NEONATAL HYDROCEPHALUS - MECHANISMS AND CONSEQUENCES

Although hydrocephalus is a multifactorial disorder, the processes res ponsible for neurologic impairment can be classified into primary and secondary mechanisms. Primary mechanisms include mechanical compressio n and stretching of brain parenchyma, ischemia and anoxia, cerebral ed ema, and blood brain barrier dysfunction. These processes lead to seco ndary mechanisms, which include cytologic and cytoarchitectural altera tions of neurons, reduced size and numbers of cerebral microvessels, a xonal degeneration and demyelination, and so on. Shunting studies sugg est that neuronal cell death may not play a major role until severe st ages of hydrocephalus and that some impairments in connectivity can be reversed. Relatively early shunting may alleviate many of the patholo gic features of hydrocephalus, but residual impairments in neurotransm itter levels and dependence on anaerobic respiration leave the treated hydrocephalic brain vulnerable to subsequent insults.