Trastornos hidroelectrolíticos en postoperados de tumores cerebrales

Introduction: Fluid and electrolyte disorders such as diabetes insipidus, salt wasting syndrome (SWS) and syndrome of inappropriate antidiuretic hormone secretion (SIADH) can appear in the immediate postoperative period after surgery for brain tumors. Early diagnosis and treatment are important to prevent the potential adverse effects of these disorders on the central nervous system (CNS). Objectives: To determine the incidence and characteristics of fluid and electrolyte disorders in the immediate postoperative period after surgery for CNS tumors in children treated in our hospital. Material and methods: We retrospectively analyzed clinical and laboratory data in all infants and children who underwent surgery for CNS tumors in our hospital from January 1998 to June 2005 and who met the laboratory criteria for diabetes insipidus, SWS or SIADH. Results: Twenty-three electrolyte disorders were identified in 149 surgical patients (an incidence of 15.4%). The median age was 5 years and 3 months (from 6 months to 17 years) and 48.7% of the patients were male. The most frequent electrolyte disturbance was diabetes insipidus (65.2% of all electrolyte disorders). On average, onset of diabetes insipidus occurred 19 hours after surgery. Treatment with desmopressin was administrated in all patients. On average, diabetes insipidus was resolved 73 hours after diagnosis, except in one patient with permanent diabetes insipidus due to a surgical lesion of the hypothalamic-pituitary axis. The second most frequent electrolyte disturbance was SWS (26.1%) with a mean time of onset of 50.4 hours after surgery. On average, SWS was resolved 57.6 hours after administration of saline solutions. Only two patients developed SIADH, which was treated with water restriction and adequate sodium supply. Both cases of SIADH resolved spontaneously in the first 36 hours after diagnosis. At discharge, none of the patients showed neurological disturbances due to an electrolytic disorder. Conclusions: In our series, the most frequent electrolyte disorder after surgery for CNS tumors was diabetes insipidus. Early treatment with desmopressin almost always prevents hypernatremia. Unless there is a surgical lesion of the hypothalamic-pituitary axis, spontaneous resolution will take place in 3 days on average. The management of SWS and SIADH requires close monitoring of plasma sodium due to the risk of hyponatremia.