Abstract
Reye syndrome is an acute non-inflammatory encephalopathy that can be precipitated by toxic, infective, metabolic or hypoxic upsets. The biochemical changes point to mitochondrial dysfunction and this is substantiated by structural changes in mitochondria on electron microscopy. The toxic metabolites that accumulate are similar to those incriminated in hepatic encephalopathy and other metabolic diseases. These metabolites exert their deleterious effects by direct neuronal damage, neurotransmitter blockade, vascular damage, cerebral oedema, hypoxic ischaemic damage, demyelination, retardation of brain growth and neuronal storage. Brain capillary endothelial cells are very rich in mitochondria and mitochondrial disorders can effect the central nervous system primarily, and not just as a consequence of systemic metabolic upset.