gms | German Medical Science

Objective: Dysnatremia is a frequently encountered phenomenon in critical ill patients and associated with a higher incidence of poor outcome and death. Potential reasons for electrolyte disturbances in neurologically ill patients can be derived from transient or permanent impairment of hypothalamic function. In this retrospective study, we investigated the course and prognostic relevance of changes in serum sodium concentrations after aneurysmal subarachnoid hemorrhage (aSAH) focusing on the very early interval after aneurysm rupture.

Method: 264 consecutive patients with aSAH admitted to our department between January 2008 and April 2012 were retrospectively analyzed. Changes in serum sodium concentration (SSC) and occurrence of hypernatremia were correlated with initial neurological status. Additionally, the prognostic relevance for neurological outcome at discharge and at 12 month was analyzed using logistic regression analysis.

Results: Initial SSC did not correlate with clinical admission grade (good versus poor), whereas SSC at 56 hours correlated significantly with WFNS grade at admission (r=0.328, p<0.001). The odds for hypernatremia were more than twofold in patients with poor initial neurological grade (OR 2.386 [95% CI 95% CI 1.381-4.123]; p=0.002). SSC at 56 hours strongly correlated with neurologcal outcome at discharge (p<0.001, r=-0.447) and after 12 months (p<0.001, r=0.301).

Conclusions: The occurrence and the extent of hypernatremia within the first 3 days after aSAH may be considered as an endocrinological marker for early brain injury and therefore as a surrogate for neurological outcome after SAH. However, future studies should also investigate anatomical correlates for early structural hypothalamus damage, in relation to sodium dysbalance to better elucidate exact pathomechanism and resulting therapeutic options.