Transient thalamic changes on MRI in a child with hypernatremia.

Severe hypernatremia has been associated with a wide variety of central nervous system lesions. Neurologic sequelae are the usual outcome in those cases in which a lesion has been documented neuroradiologically. The authors report a 7-month-old male with severe hypernatremia who developed obtundation after correction of the electrolyte imbalance. Magnetic resonance imaging revealed bilateral thalamic signal changes that resolved on follow-up study, in accordance with complete clinical recovery. To the authors' knowledge, bilateral thalamic signal changes are previously unreported findings associated with hypernatremia. Pertinent literature and the clinical course of the authors' patient are the basis for questioning currently recommended guidelines for the rate of correction of hypernatremia.