Intravenous Immune Globulin and Pseudohyponatremia

Abstract

To the Editor: A 49-year-old woman admitted with typical Guillain–Barré syndrome was treated with intravenous immune globulin (Gamimune N 10%, Bayer, Elkhart, Ind.), at a dose of 45 g per day (0.4 g per kilogram of body weight) for five days. The sodium concentration, measured with the use of an ion-selective electrode in diluted serum specimens (“indirect potentiometry”), decreased from 143 mmol per liter on day 1 to 127 mmol per liter on day 4. On day 5, when the serum sodium concentration was 122 mmol per liter, urine osmolality was 474 mOsm per liter, the urinary sodium concentration was . . .