Severe hyponatraemia secondary to beer potomania complicated by central pontine myelinolysis

A case of severe hyponatraemia in a 56-year-old male alcohol misuser secondary to beer potomania is presented. In view of severe volume depletion and the patient's inability to drink, normal saline was cautiously infused. Despite initial improvement, he subsequently deteriorated neurologically. Magnetic resonance imaging demonstrated the classical lesion of central pontine myelinolysis (CPM). The rate of correction of plasma sodium was within limits normally considered safe. Beer potomania should be considered as a cause of hyponatraemia in alcohol misusers. Recognition is important as the electrolyte imbalance repairs simply with cessation of alcohol intake and institution of normal diet. Correction of chronic hyponatraemia by infusion of normal or hypertonic saline should not be attempted unless life-threatening neurological complications supervene. When the balance of risks favours correction, caution should be exercised, as CPM may occur. Although a rate of correction of plasma sodium of up to 10 mM per 24-hour period has been associated with a low risk of precipitating CPM, this case illustrates that a completely safe rate of correction probably cannot be defined.