[Electrolyte changes in acute leukemia in childhood]

Electrolyte imbalance in leukemia can be due to either organ infiltration and cell death or to a side effect of cytostatic drugs. From the wide variety of these disturbances seen in acute leukemias in childhood, the excess of potassium is most dangerous. Further electrolyte changes, which are however less evident, are hyperphosphataemia, hyperphosphaturia, and hypocalcaemia. The destruction of a large amount of cells during aggressive induction therapy can boost the electrolyte imbalance and therefore lead to renal failure. Such situations are demonstrated in two cases. Following Vincristine and Cyclophosphamide administration, electrolyte changes such as acute or prolonged decrease of sodium in the serum and urinary loss of sodium are seen frequently. Based on the data from 20 patients with acute lymphoblastic leukemias we describe the dynamics of this process. These changes are probably caused by the syndrome of inadequate ADH-secretion. The clinical importance of these findings are discussed and procedures for improving therapy are set out.