Summary

This case describes a 54-year-old woman with exudative eczema, who was admitted to the intensive care unit with a serum sodium concentration of 191 mmol/L, secondary to profound dehydration in the context of group A streptococcal septicaemia. Successful rehydration and electrolyte normalisation was achieved with continuous venovenous haemodiafiltration (CVVHDF), the replacement fluid of which was infused with hypertonic saline to limit the rate of sodium reduction. This case report comments on three areas of interest. First, hypernatraemia of this level is unusual. Second, the infusion of hypertonic saline into the replacement fluid of the CVVHDF filter is not common practice but successfully ensured a controlled reduction in serum sodium concentration while aggressively replacing a 9 L water deficit. Third, the notable physiological reserve demonstrated by the patient: despite an extraordinary serum sodium concentration in the context of overwhelming streptococcal septicaemia, she has made a full cognitive recovery.