Abstract
Excess water diuresis can develop during treatment of chronic hyponatremia caused by psychogenic polydipsia, often resulting in overcorrection of the serum sodium level, leading to irreversible damage of the central nervous system. We report the case of a patient with severe chronic hyponatremia whose serum sodium level was successfully corrected by continuous infusion of low-dose vasopressin. The patient was a 64-year-old man who had a history of treatment for schizophrenia and psychogenic polydipsia. He was brought to the ER of our hospital by ambulance due to consciousness disturbance, and his serum sodium level was 102 mEq/L. His condition was complicated by bacterial pneumonia and rhabdomyolysis. After admission to the intensive care unit, he excreted a large amount of diluted urine, resulting in intravascular volume depletion and a rapid increase in the serum sodium level associated with intractable hypotension. We then initiated continuous infusion of vasopressin at a dose of 0.25 units per hour, resulting in increased urine osmolality, reduction of the urine volume, and resolution of hypotension. Thereafter, the serum sodium level normalized at an appropriate rate of correction. We suggest that in cases of severe chronic hyponatremia, continuous infusion of low-dose vasopressin can prevent overcorrection of the serum sodium level, particularly in cases associated with infectious complications.
