[Marked hyponatremia with consciousness disturbance probably caused by linezolid in a patient with acute myeloid leukemia].

We report the case of a 75-year-old man with acute myeloid leukemia who developed hyponatremia after linezolid administration. Because induction therapy did not achieve complete remission for this man, we initiated re-induction therapy with enocitabin and daunomycin. Seven days after chemotherapy, the patient experienced a catheter-related blood stream infection (CRBSI) due to methicilin resistant staphylococcus aureus (MRSA). When treatment with albekacin and fosfomycin was in effective, linezolid was administrated intravenously and he became afebrile. On day 8 after linezolid administration, however, he reported general fatigue and slight consciousness disturbance. His serum sodium concentration was 119 mEq/L and his urinary sodium excretion rose to 143 mEq/day, although intravenous sodium intake was 98 mEq/day. Because of the sufficiency of urine volume and weight loss, we surmise that inappropriate ADH secretion (SIADH) syndrome was unlikely. We diagnosed renal salt wasting syndrome (RSWS) based on calculation of the amount of sodium intake and the amount of sodium excreted from the kidneys. After linezolid was discontinued and aggressive treatment with sodium supplement begun, his consciousness cleared as his low serum sodium level rose. This is, to the best of our knowledge, the first case reported on the development of RSWS after linezolid treatment. Although the process remains unclear, our case suggests that linezolid may induce RSWS after intensive chemotherapy.