gms | German Medical Science

Objective: To examine the incidence and risk factors for the occurrence of electrolyte disorders after traumatic brain injury (TBI).

Methods: A retrospective analysis of hospital records and digital imaging was conducted for patients admitted to our intensive care unit for mild, moderate or severe TBI for a minimum of 4 days. Demographic variables, modified Rankin Scale (mRS) scores and serum chemistry panels were reviewed and used in regression models to predict outcome.

Results: Between September 2008 and September 2018, 420 patients with TBI and complete records were included in our analysis. On admission, a mild TBI was noted in 26.6% of patients, a moderate TBI in 12.0% and a severe TBI in 61.4%. While the mild TBI subgroup presented with an mRS >1 in 35.9% of cases, the moderate (75.9%) and severe (98.0%) TBI groups presented significantly more often with a substantial neurological deficit. These proportions decreased non-significantly to 29.6% for mild TBI (p=0.629), significantly to 51.7% for moderate TBI (p=0.008) and significantly to 72.7% for severe TBI (p<0.001) by discharge. Patients with a severe TBI underwent at least one surgical intervention in 82.4%, which was significantly more frequent than patients with mild (32.8%; p<0.001) and moderate TBI (58.6%; p<0.001). Hyponatremia represented the most common electrolyte disorder and was noted in 23.7% of all patients, without significant difference between TBI grades. Hypernatremia was seen significantly more often among patients with severe TBI (48.0%) versus both mild (17.2%) and moderate TBI (20.7%; p<0.001). The binary logistic regression model revealed that patients with severe TBI (OR 3.15; p=0.005) and at least 2 surgical interventions (OR 3.11; p=0.024) were more likely to develop hyponatremia, while the presence of intraventricular hemorrhage or symptomatic vasospasms did not contribute to the model. When controlling for age, TBI grade and number of surgical interventions, the presence of hyponatremia prolonged the hospital stay by an average of 10 days (p<0.001).

Conclusion: Hyponatremia represents the most common electrolyte disorder occurring after TBI and is associated with a delayed hospital discharge. Patients with severe TBI and multiple surgical interventions are more likely to develop hyponatremia.