Blood markers of cerebral vasospasm after aneurysmal subarachnoid hemorrhage: a narrative review of current literature.

Introduction: There have been growing efforts to identify predictors of Cerebral Vasospasm to facilitate earlier diagnosis and establish patient predictive models. This review discusses the implications of serum electrolytes, glycemic indices, and inflammatory markers in predicting the occurrence of aSAH-induced CV. Methods: The literature was reviewed across PubMed, Scopus, Web of Science, Google scholars, the National Center for Biotechnology Information, the Centers for Disease Control and Prevention, the World Health Organization, and the National Institutes of Health. Studies were included within the following criteria: (a) focused on CV in human and (b) were published in peer-reviewed journals. Results: Studies included in this review comprised retrospective analyses, prospective studies, and systematic reviews. The literature suggests that hyponatremia is associated with the presence of CV post-aSAH. It is frequently encountered in the early phase postictally, emanating from the syndrome of inappropriate antidiuretic hormone secretion and cerebral salt wasting syndrome. Hyperglycemia, leukocytosis, elevated C-reactive protein levels and elevated cerebrospinal interleukin-6 levels also appear to be associated with the occurrence of CV post-aSAH. Conclusions: The studies included in this review suggest that the presence of hyponatremia, hyperglycemia, leukocytosis, and elevated CRP and CSF IL-6 levels are associated with the occurrence of CV post-aSAH. Further research is required to scrutinize temporal relations and causality of described markers in the setting of aSAH-induced CV. Establishing a panel of biomarkers will facilitate the development of patient predictive models. Such models may stratify patient groups, institute therapeutic and endovascular interventions and ultimately reduce vasospasm-associated morbidity and mortality to improve patient outcomes.