This issue is important for forensic pathologists who must distinguish natural disease from trauma. The current investigation included a small retrospective review of autopsy findings in deceased children with elevated vitreous sodium values; a larger retrospective chart review of hospitalized hypernatremic children; a complementary retrospective chart review of hospitalized children with subdural hemorrhages; a review of cases of fatal head injury with hospitalized survival intervals and post-injury hypernatremia; a critical review of the literature; and a review of recent anecdotal cases of severe hypernatremia. Contrary to the older literature, which theorized a causal relationship between hypernatremia and subdural hematomas, this study could not identify a cause-and-effect relationship between hypernatremia and the subsequent development of subdural hematoma. If there is a cause-and-effect relationship, this study's data suggest that it must be extremely rare. The authors thus conclude that hypernatremia may occur as one of myriad complications that can arise in critically ill children, with or without intracranial pathology. 3 tables and 23 references