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Abstract

Introduction: Survivors of pediatric brain tumors often suffer from important neurologic disabilities. Risk of disability has been associated with non-modifiable tumor characteristics, age, and adjunct treatments. Hyponatremia is known to complicate surgical procedures for brain tumors and potentially cause secondary brain injury. Methods: Retrospective cohort of children 0–18 years undergoing a first procedure for an intracranial tumor. Sodium (Na) levels of ≤130 and ≤135 mEq/L were evaluated. A Pediatric Cerebral Performance Category (PCPC) score at hospital discharge was assigned. PCPC score was dichotomized by normal or mild disability (1–2) versus poor outcome (moderate disability - brain death or ≥3–6) for multivariable analyses. Interval PCPC score (1–6) was used with other measures. Results: 319 patients were identified. Na ≤130 mEq/L occurred in 39 (12%) and Na ≤135 mEq/L occurred in 176 (55%) patients. Poor outcome occurred in 80 (25%) patients. In models adjusted for patient age and tumor factors (malignant histology, hydrocephalus, tumor location), Na ≤130 mEq/L was independently associated with poor outcome (adjusted Odds Ratio 6.2, 95% confidence interval 3.0–13.3). Furthermore, Na nadir, duration of Na ≤130 and ≤135 mEq/L, and number of episodes with Na ≤130 and ≤135 mEq/L were associated with higher PCPC scores (all p<<.001). Decreases in Na >10 or >15 mEq/L in 24 hours were uncommon (9% and 4% of all patients, respectively), but both were associated with higher PCPC scores (p=.002 and .01, respectively). Conclusions: Hyponatremia is an independent risk factor for poor neurologic outcome in post-operative pediatric brain tumor patients. Increased severity, duration, and number of episodes of hyponatremia were significantly associated with worsening PCPC scores, supporting the association of acute hyponatremia with poor outcome. Hyponatremia is a potentially modifiable risk factor for disability, and further research is needed to determine if prevention or treatment of hyponatremia can improve neurologic outcome in these children.