The relation of early hypernatremia with clinical outcome in patients suffering from aneurysmal subarachnoid hemorrhage

• We analyzed the serum sodium concentration after aneurysmal subarachnoid hemorrhage.
• Hypernatremia within 56 h may relate to early brain injury.
• Hypernatremia is a predictor for poor neurological outcome.
• The increase in sodium concentration correlates with the extent of early brain injury.
• There is no correlation with the occurrence of delayed cerebral ischemia.

ObjectiveSodium dysregulation in the course after aneurysmal subarachnoid hemorrhage (aSAH) has been identified as one contributor to adverse clinical outcome. However, the correlation of acute dysnatremia and early brain injury (EBI) remains unclear. We investigated the early course and prognostic relevance of changes in serum sodium concentrations and its relation to EBI after aSAH.MethodsRetrospectively, the serum sodium concentration (SSC) of 264 patients with aSAH was analyzed. The first SSC was obtained within 8 h after initial ictus and then repeatedly analyzed every 8 h over the first five days. Incidence of hypernatremia (defined as SSC > 145 mmol/l) was correlated with initial neurological condition according to World Federation of Neurological Surgeons grade (WFNS), incidence of delayed cerebral ischemia (DCI) and clinical outcome at 12 month according to modified Rankin Scale (mRS).ResultsWithin 56 h, 82 patients (31.1%) developed hypernatremia which correlated significantly with initial neurological condition (p < 0.001). Initial SSC within 8 h after SAH did not correlate with patient outcome at 12 month (r = −0.026, p = 0.694), however SSC obtained 56 h after ictus did significantly (r = 0.365, p < 0.001; OR 4.14 95% CI (1.84–9.31)). A correlation with the incidence of DCI was not found (r = 0.079, p = 0.217).ConclusionThe occurrence of hypernatremia within 56 h after aSAH was shown to be an independent predictor for poor neurological outcome. Early serum sodium levels after aSAH can be considered as surrogate markers to predict outcome after aSAH irrespective to the occurrence of DCI. However, prospective studies are necessary to validate this concept.