Cerebral Salt Wasting Syndrome in Post-Operative Pediatric Brain Tumor Patients

Background Cerebral salt wasting syndrome (CSWS) and the syndrome of inappropriate antidiuretic hormone (SIADH) are both causes of hyponatremia in pediatric neurosurgical patients often with similar presenting symptoms; however, despite similar clinical characteristics the treatment for CSWS and SIADH can be drastically different, which makes the distinction critical for post-operative treatment. Further complicating matters, are the exact mechanism for CSWS which remains unclear, and the incidence and severity of CSWS is not well studied in pediatric neurosurgical patients. We hypothesized that CSWS occurs frequently in post-operative brain tumor patients and is an important cause of post-operative hyponatremia in these patients. Methods We designed a single institution retrospective cohort study of all pediatric brain tumor patients undergoing craniotomy for tumor resection at our institution between January 2005 and December 2009. Results Of the 282 patients undergoing 291 operations, post-operative CSWS was identified in 15 cases (5%), and was more frequently observed than SIADH (nine cases, 3%). Median onset of CSWS was on post-operative day 3, lasting a median of 2.5 days. Patients with CSWS were more likely to have suffered post-operative stroke (40 vs. 4.6%, P < 0.001), have chiasmatic/hypothalamic tumors (40 vs. 3.8%, P = 0.002), and be younger (mean age 5.9 vs. 9.7 years, P = 0.01) than eunatremic patients. In addition, nearly half of the patients with CSWS (47%) had post-operative hyponatremic seizures. Conclusion The diagnosis of CSWS should be strongly considered in hyponatremic pediatric patients with significant natriuresis following brain tumor resection, and a treatment initiated promptly to prevent neurologic sequeleae.