The role of electrolyte disturbances in traumatic brain injury: a 5-day longitudinal analysis in isolated TBI patients

Abstract Objectives Electrolyte disturbances are common but poorly characterized complications of traumatic brain injury (TBI) and may contribute to secondary injury and worse outcomes. This study evaluated the prevalence, temporal trends, and prognostic significance of common electrolyte abnormalities in patients with moderate-to-severe TBI. Methods A prospective observational study was conducted at a tertiary neurosurgical center from July to December 2024. Consecutive patients with isolated TBI and a Glasgow Coma Scale (GCS) score ≤ 12 were included; polytrauma cases were excluded. Serum sodium (Na⁺), potassium (K⁺), chloride (Cl⁻), and bicarbonate (HCO₃⁻) were measured daily for five days. Outcomes included length of stay and Glasgow Outcome Scale (GOS) score at discharge. Pearson correlation and linear regression were used ( p < 0.05). Results Fifty patients were analyzed (mean age 38.4 ± 20.2 years; 68% male). Hyponatremia (52%) was most frequent, followed by hypokalemia (36%). Hyponatremia, hypokalemia, and hypochloremia correlated with poorer GOS scores and longer hospitalization. Low bicarbonate levels were associated with unfavorable outcomes, while higher levels correlated with shorter stays. Electrolytes gradually normalized over five days. Conclusion Hyponatremia and hypokalemia independently predicted worse neurological outcomes and prolonged hospitalization. Serum bicarbonate emerged as a potential prognostic biomarker, with lower levels indicating greater secondary injury and poorer recovery.