Traumatic Brain Injury Patients With a Glasgow Coma Scale Score of <= 8, Cerebral Edema, and/or a Basal Skull Fracture are More Susceptible to Developing Hyponatremia

Background: Traumatic brain injury (TBI) is a common injury treated at the neurosurgery department. The incidence rate is approximately 3% in the general population and the mortality rate is 25%. The incidence of hyponatremia following TBI is 33%. Hyponatremia is one of the main causes of disability and/or death in TBI patients. This study investigated the epidemiology of hyponatremia following TBI. Methods: Patients who were admitted to our hospital with moderate or severe TBI were analyzed retrospectively. The relationship between the occurrence of hyponatremia and age, sex, type of injury, Glasgow coma scale (GCS) score, whether the patient underwent surgery, and the presence of cerebral edema and basal skull fracture was analyzed statistically using a chi(2) test and multivariate logistic regression analysis. Results: Out of the 136 patients recruited for the study (81 males and 55 females; mean +/- SD age of 48 +/- 13 y), 56 suffered from hyponatremia (ie, serum sodium level <135mmol/L). Univariate analysis indicated that hyponatremia following TBI was not related to age (P>0.05), sex (P= 0.347), or surgical history (P= 0.492) but that it was related to the type of injury (P= 0.031), a GCS score <= 8 (P< 0.001), the presence of cerebral edema (P< 0.001), and/or a basal skull fracture (P< 0.001). Multivariate logistic regression analysis confirmed a strong association between the occurrence of hyponatremia and a GCS score <= 8 (P< 0.016), the presence of cerebral edema (P< 0.001), and a basal skull fracture (P< 0.001). Conclusions: TBI patients with a GCS score <= 8, cerebral edema, and/or a basal skull fracture are particularly prone to developing hyponatremia. These patients require additional treatment that should entail the normalization of serum sodium levels to prevent deterioration of their condition.