RHABDOMYOLYSIS AFTER CORRECTION OF HYPONATREMIA DUE TO PSYCHOGENIC POLYDIPSIA POSSIBLY COMPLICATED BY CLOZAPINE

OBJECTIVE: To report a case of rhabdomyolysis related to rapid correct ion of hyponatremia attributable to compulsive drinking of water, poss ibly complicated by clozapine use. CASE SUMMARY: A 42-year-old white m an treated with clozapine for schizophrenia was admitted for a general ized seizure. Marked hyponatremia due to psychogenic polydipsia was pr esent. He developed a marked elevation of creatine kinase concentratio ns after correction of hyponatremia with hyperosmolar sodium solution, without clinical signs of rhabdomyolysis. DISCUSSION: Rhabdomyolysis associated with hyponatremia due to water intoxication has been report ed in 17 patients to date. A possible explanation may lie within the f ramework of the calcium-sodium exchange across the skeletal muscle cel l membrane. By increasing muscle cell permeability, clozapine treatmen t may possibly enhance the destruction of muscle cells. CONCLUSIONS: H yponatremia due to water intoxication and concurrent use of clozapine should be considered in the differential diagnosis of rhabdomyolysis, especially in the severely psychiatrically disabled population.