Integrative Evaluation of Serum Ionic Magnesium and Calcium Levels, Pupillary Reactivity, and Clinical Parameters as Predictors of Neurological Outcomes in Patients with Traumatic Brain Injury

Background: Traumatic brain injury (TBI) is a leading cause of disability and death worldwide, yet prognostication remains challenging. While the Glasgow Coma Scale (GCS) and pupillary reactivity are well - established clinical indicators, growing evidence suggests that electrolyte disturbances, particularly hypomagnesemia and hypocalcemia, may further refine outcome predictions. Objective: To evaluate the combined role of serum ionic magnesium (Mg??) and calcium (Ca??) levels, alongside pupillary reactivity and clinical parameters, in predicting neurological outcomes among severe TBI patients in a tertiary care hospital. Methods: This 12 - month prospective observational study (June 2023 ? May 2024) was conducted at a tertiary - care hospital. Patients aged 18?80 years with severe TBI (GCS ? 8) presenting within 24 hours of injury were enrolled. Isolated brainstem injuries were excluded due to unique management constraints. Serum Mg?? and Ca?? were measured on day 0 (admission), day 3, and day 7. All patients received Level III ICU care, guided by Brain Trauma Foundation protocols for TBI management, including intracranial pressure (ICP) monitoring when indicated. Ethical clearance was obtained from each institution?s review board. Neurological outcomes at 6 months were assessed using the Glasgow Outcome Scale (GOS), dichotomized into poor (GOS ? 3) and good (GOS > 3). Logistic regression identified independent predictors of poor outcome. Results: A total of 84 patients (mean age: 50.4 ? 15.7 years; M: F ratio ~ 2: 1) were included. Ventilatory support was required in 63%, and ICP monitoring was performed in 42%. Hypomagnesemia (<1.6 mEq/L) at admission showed a significant association with poor outcomes (odds ratio [OR] = 6.6, p = 0.002), while hypocalcemia (<1.14 mmol/L) on day 3 was similarly linked to worse prognoses (OR = 4.2, p = 0.015). Nonreactive pupils conferred an 8.2 - fold increased risk of poor outcome (p < 0.001). Age and sex were not significant predictors. Multivariate analysis incorporating Mg??, Ca??, and pupillary reactivity demonstrated improved predictive accuracy (area under the curve = 0.87). Conclusion: Hypomagnesemia and hypocalcemia were significant adjunctive predictors of poor neurological outcomes in severe TBI, particularly when combined with pupillary assessment and conventional measures. Day 3 and day 7 electrolyte measurements capture peaks of metabolic derangement crucial for risk stratification. Early identification of these disturbances may inform therapeutic interventions to optimize neurological recovery.