Recurrent rhabdomyolysis secondary to hyponatremia in a patient with primary psychogenic polydipsia.

Rhabdomyolysis is characterized by the destruction of skeletal muscle tissue, and its main causes are trauma, toxic substances and electrolyte disturbances. Among the latter is hyponatremia-induced rhabdomyolysis, a rare condition that occurs mainly in patients with psychogenic polydipsia. Psycogenic polydipsia mostly affects patients with schizophrenia, coursing with hyponatremia in almost 25% of the cases. It is also in this context that rhabdomyolysis secondary to hyponatremia occurs most often. In this article, the case of a 49-year-old male with a history of schizophrenia, medicated with clozapine, and brought to the emergency room in a state of coma and seizures is described. Severe hypoosmolar hyponatremia with cerebral edema was found on a computed tomography examination, and a subsequent diagnosis of hyponatremia secondary to psychogenic polydipsia was made. Hyponatremia correction therapy was started, and the patient was admitted to the intensive care unit. After the hyponatremia correction, the patient presented with analytical worsening, showing marked rhabdomyolysis with a creatine phosphokinase level of 44.058 UI/L on day 3 of hospitalization. The condition showed a subsequent progressive improvement with therapy, with no occurrence of kidney damage. This case stresses the need for monitoring rhabdomyolysis markers in severe hyponatremia, illustrating the condition of rhabdomyolysis secondary to hyponatremia induced by psychogenic polydipsia, which should be considered in patients undergoing treatment with neuroleptics.