Behavioural changes due to pontine and extrapontine myelinolysis.

OBJECTIVE: To report a case of central and extrapontine myelinolysis with unusual behavioural manifestations that developed after slow (not more than 0.5 mmol sodium per litre per hour) correction of hyponatraemia. CLINICAL FEATURES: A 51-year-old Caucasian woman with hyponatraemia caused by psychogenic polydipsia experienced a delayed onset of behavioural changes with some ataxia, but no pyramidal signs, after correction of the hyponatraemia. INTERVENTION AND OUTCOME: The hyponatraemia was corrected with a combination of hypertonic saline and fluid restriction at the currently recommended rate of not more than 0.5 mmol of sodium per litre per hour. CONCLUSION: Central and extrapontine myelinolysis may develop after slow correction of hyponatraemia. Behavioural manifestations may be the most prominent clinical feature.