A Prospective Study on Hyponatremia in Traumatic Brain Injury

Background Hyponatremia is the commonest electrolyte imbalance in traumatic brain injury (TBI) with a reported incidence of 15 to 20%. Methodology A prospective observational analytical study was conducted from January 2015 to December 2015. Mild and moderate TBI patients aged between 13 and 65 years, with no comorbid conditions were included in the study. Patients were monitored for hyponatremia, and etiology was found out using standard investigation protocol. Results A total of 153 patients were included in the study. Incidence of hyponatremia was 21.6% (33/153). Cerebral salt wasting syndrome was more common than syndrome of inappropriate secretion of antidiuretic hormone. Incidence was higher in patients with low Glasgow coma scale score (p = 0.001) and in patients with parenchymal contusions (p = 0.008). Incidence correlated well with Marshal computed tomography (CT) score (p = 0.013). No significant difference of incidence was noted in relation to age or gender. Patients with hyponatremia had significantly prolonged intensive care unit (p < 0.001) and hospital stay (p < 0.001). Outcome at discharge was worse in patients with hyponatremia (p = 0.002), whereas both groups had similar outcome at 3-month follow-up (p = 0.087). Conclusions Hyponatremia is a very common electrolyte imbalance in patients of TBI. Marshal CT grading and initial Glasgow coma scale score correlate well with the incidence of hyponatremia. More aggressive sodium monitoring may be required in parenchymal contusions in view of increased chance of development of hyponatremia. Hyponatremia adversely affect the immediate outcome in TBI, while long term outcome is usually unaffected.