Rhabdomyolysis Following Rapid Correction of Acute Hyponatraemia in a Patient With Psychogenic Polydipsia.

Rhabdomyolysis is a recognised but under-reported complication of acute hyponatraemia and its treatment, particularly in patients with psychogenic polydipsia. We report a case of a male in his 50s with recurrent psychogenic polydipsia who developed severe rhabdomyolysis as a potential result of both hyponatraemia and its subsequent rapid correction. Serum sodium was 117 mmol/L on admission and increased to 131 mmol/L within six hours on venous blood gas sampling following administration of hypertonic saline. Creatine kinase (CK) was already elevated at admission and rose sharply following rapid administration of hypertonic saline, peaking at 60,672 U/L, with preserved renal function throughout admission. Alternative causes of rhabdomyolysis were explored and systematically excluded. This case highlights the importance of cautious sodium correction, continued biochemical monitoring beyond initial stabilisation, and consideration of CK surveillance in high-risk patients.