[Syndrome of inappropriate ADH secretion: a late complication of hemopoietic stem cell allograft].

An 11-year old boy with acute lymphoid leukemia underwent umbilical cord stem cell infusion. This was followed at day 15 by the onset of asymptomatic hypotonic isovolemic hyponatremia. The disorder could be attributed to a syndrome of inappropriate ADH secretion (SIADH), most probably related to the massive i.v. induction treatment with cyclophosphamide. The major causes and clinical variants of SIADH are reviewed, with particular emphasis on the complications of chemotherapy in hematological diseases. Worsening of hyponatremia during routine parenteral feeding, as opposed to normalization of plasma Na+ by infusion of hypertonic saline, emphasize the importance of early accurate diagnosis and careful follow-up of these iatrogenic sequelae of stem cell allograft.