Therapeutic relowering of the serum sodium in a patient after excessive correction of hyponatremia

Background: Inappropriate correction of chronic hyponatremia could lead to major neuropathological sequelae. In man, the risk of brain myelinolysis in creases strikingly when correction of the serum sodium exceeds 10-15 mEq/l/ 24 h. No treatment is actually available for this iatrogenic brain injury. However, recent experimental data showed that rapid reinduction of the hypo natremia greatly reduces the incidence of brain damage and death in case of serum sodium overshooting. Subjects and methods: We tested this rescue man oeuver in a 71-year-old woman with nausea, confusion and severe (SNa 106 mE q/l) chronic hyponatremia related to thiazides. It was associated with hypo kalemia (SK: 3.2 mEq/l). Results: Treatment with isotonic saline produced i nappropriately high SNa correction level of +21 mEq/l after the first 24 h. After initial improvement, the neurological status deteriorated after 72 h . Rapid reinduction of the hyponatremia was then ordered. Administration of hypotonic fluids (by oral and i.v. route) combined with dDAVP induced a pr ompt decline in the SNa(-16 mEq/l/14 h) with a final gradient of correction of Delta SNa +9 mEq/l. This manoeuver was well tolerated without untoward effects. The natremia then progressively normalized and the patient complet ely recovered without neurological sequelae. Conclusion: Hypotonic fluids m ay be safely administered to decrease the natremia after excessive correcti on of hyponatremia for potential prevention of myelinolysis.