Serum Magnesium as a Marker of Neurological Outcome in Severe Traumatic Brain Injury Patients

Hypomagnesemia is postulated as one of the important determinants of outcome following traumatic brain injury (TBI) through its effect on secondary injuries to neurons. AIMS AND OBJECTIVE: The aim of this study was to determine the relationship between serum magnesium level and neurological outcome in patients admitted with severe head injury. MATERIALS AND METHODS: In this prospective study, patients admitted with severe TBI were recruited and dichotomized into low serum magnesium group and normal serum magnesium group based on the initial serum magnesium level. Data were collected regarding age, sex, and Glasgow Coma Scale at admission. Neurological outcome of the patients in these groups was assessed using Glasgow Outcome Scale at 6 months. RESULTS: Seventy-two patients (male = 50, female = 22) with a mean (±standard deviation) age of 42.5 (±12.7) years were studied. Forty-two (58%) patients had low serum magnesium level (<1.3 mEq/L) at admissions. At 6-month follow-up, 81% of patients with poor neurological outcome had low serum magnesium as compared to 19% of patients with good outcome (P = 0.01). Hypomagnesemia was associated with poor neurological outcome (odds ratio = 2.1, P = 0.04, 95% confidence interval = 1.0–8.8) on regression analysis. CONCLUSION: Hypomagnesemia appears to be an independent prognostic marker in patients with severe TBI.