[Neurogenic hypernatremia syndrome in children]

Chronic "neurogenic" hypernatremia is the consequence of defective thirst mechanism either alone or in combination with impaired osmoregulation of ADH release. Both the specific receptors and the structures involved in hormonal secretion are localised in the hypothalamic area. "Neurogenic" hypernatremia can be secondary to a hypothalamic lesion of different type (neoplastic, vascular, malformative) or rarely it can be idiopathic. We present three cases: two females 4 and 5 months old, affected by cerebral malformations involving midline structures of the brain (III ventricule, corpus callosum etc.) and a male 4 years old with a idiopathic form. We discuss the relationship between the origin of the cerebral malformations and the ontogeny of the structures involved in the control of the osmolarity. Moreover we have observed that the hypernatremia in associated with hyperlipemia: the pathogenetic hypothesis explaining this abnormality are discussed.