INTRANASAL DESMOPRESSIN-INDUCED HYPONATREMIA

Desmopressin is a commonly used, well-tolerated agent for the treatmen t of primary nocturnal enuresis and central diabetes insipidus. Intran asal desmopressin provides symptomatic relief with few serious complic ations. A 29-year-old woman with a long history of primary nocturnal e nuresis began treatment with intranasal desmopressin. Although the enu resis ceased, she developed throbbing headaches, nausea, vomiting, par esthesia, lethargy, fatigue, and altered mental status over the next 7 days. When she came to the emergency room her sodium concentration wa s 127 mmol/L. The history of desmopressin use was not obtained at that time. She was treated with intravenous fluids and discharged. The sym ptoms returned and worsened over the next 4 days, and she returned to the emergency room stuporous. A repeat sodium was 124 mmol/L, and she was admitted. The history of desmopressin use was still not available. Medical. evaluations included computerized tomography lumbar puncture , complete blood counts, serum chemistries, and serologies. The next m orning the woman was improved and informed clinicians of her desmopres sin use. Without other causes for the hyponatremia, she was diagnosed with the syndrome of inappropriate antidiuretic hormone, presumably ca used by desmopressin. Within 24 hours of fluid restriction and cessati on of desmopressin, her symptoms and hyponatremia resolved. A review o f the literature found 11 children and 2 adults in whom intranasal des mopressin was associated with hyponatremia, all of whom experienced se izures or altered mental status. Our patient illustrates the importanc e of early recognition and treatment of hyponatremia before the onset of seizures. When vague symptoms develop during desmopressin therapy, hyponatremia must be considered as part of the differential diagnosis. It may also be prudent to screen for electrolyte abnormalities in pat ients taking this agent to prevent serious iatrogenic complications.