Endocrine Abstracts

During the warmest days reported in Wales and the United Kingdom recently, we have seen severe hyponatraemia phenomena in this part of the world. Water intoxication causes acute hyponatraemia when the sodium concentration of the blood falls too low due to prolonged sweating combined with excessive fluid consumption. Although primary polydipsia is found in a broad range of individuals including those with mental disorders, and healthy persons, as well as athletes who run marathons and long triathlons, highest hyponatremia incidence usually observed in summer months. Heatwaves or extreme weather are making these events more likely due to loss of sodium by perspiration alongside excessive hypotonic fluid intake. Interestingly, our two patients with chronic psychotic disorders had their first presentation of symptomatic dilutional hyponatremia on the same weekend when the extreme warm weather reported. Both of our patients were admitted to local emergency department after developing seizures a day after the recorded highest temperatures. They both received either 2.7% or 1.8% sodium chloride to help treat acute severe hyponatraemia, with their initial serum sodium of 106 mmol/l and 112 mmol/l respectively. Both of our patients take anti-psychotics and were relatively well prior to this event. Their family and carers reported excessive water intake a few days prior to the witnessed seizures. Both patients made excellent recovery after dyselectrolytemia correction, and they maintained the eunatremic status after recommencing their regular antipsychotics. The advice given to these patients and carers are to monitor their fluid intake, to not drink more than they are thirsting for or exceeding 2.5 litres of fluid daily, to monitor urine colour, concentration, and urinary frequency. Although a few anti-psychotics may impair thirst sensation which could disrupt homeostatic regulation of water balance and induce compulsive drinking, these strategies would be helpful to circumvent symptomatic dilutional hyponatremia as the warm weather continues.