Sudden unexpected death in young adults with chronic hydrocephalus.

We present four cases of sudden unexpected death in young adults with chronic hydrocephalus. The patients were between 20 and 28 years of age and had suffered from aqueduct stenosis (two patients), spina bifida in combination with Arnold-Chiari malformation (type II) and fragile X-syndrome. The patients suddenly collapsed with cardiorespiratory failure and could not be resuscitated and none had a history of headache or seizures. The post-mortem examinations revealed no unusual findings and a definite cause of death could not be established. Neuropathological examination revealed chronically hydrocephalic brains without any signs of uncal or tonsillar herniation. We hypothesise that a sudden pressure-induced decompensation of cerebral neuronal pathways involving insular and limbic cortex, hypothalamus and brain stem nuclei, may have caused disturbances of the cardiopulmonary control centres in the reticular formation of the brain stem, which in turn may have led to instantaneous cardiorespiratory arrest resulting in sudden "neurogenic" cardiac death.