Osmotic demyelination syndrome following rapid correction of hyponatraemia.

We report a case of a young male with adrenal hypoplasia who presented following water intoxication with severe hyponatraemia and seizures. He required a period of intensive care and over the initial 24 h his serum sodium corrected at average of 0.9 mmol x l(-1) h(-1). He subsequently developed osmotic demyelination syndrome. Following supportive treatment he made a full recovery. Severe hyponatraemia carries a risk of cerebral oedema with a significant mortality, yet correcting it too rapidly can result in osmotic demyelination syndrome, again with potentially disastrous consequences. It may be difficult to determine the duration and aetiology of the hyponatraemia and this is necessary to guide treatment. There is no consensus about the optimal rate of correction of hyponatraemia but formulae such as the Adrogue and Madias formula can be used to guide treatment with normal or hypertonic saline. Continuous veno-venous haemofiltration has been used effectively in this setting.