title: Impact of Hyponatremia on Morbidity, Mortality, and Complications After Aneurysmal Subarachnoid Hemorrhage: A Systematic Review.
abstract: BACKGROUND
  Hyponatremia is a common metabolic disturbance after aneurysmal subarachnoid hemorrhage (SAH), and it may worsen outcomes. This review aims to characterize the effect of hyponatremia on morbidity and mortality after SAH.
  
  
  OBJECTIVE
  We sought to determine the prevalence of hyponatremia after SAH, including in subgroups, as well as its effect on mortality and certain outcome measures, including degree of disability and duration of hospitalization.
  
  
  METHODS
  A search of terms "hyponatremia" and "subarachnoid hemorrhage" was performed on PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE. Studies were included if they reported prevalence of hyponatremia and if they discussed outcomes such as mortality, duration of stay, functional outcomes (e.g., Glasgow Outcomes Scale), or incidence of complications in patients with aneurysmal SAH. Two independent researchers assessed the titles and abstracts and reviewed articles for inclusion.
  
  
  RESULTS
  Thirteen studies met inclusion criteria. The prevalence of at least mild hyponatremia was 859 of 2387 (36%) of patients. Hyponatremia was associated with vasospasm and duration of hospitalization, but it did not influence mortality.
  
  
  CONCLUSIONS
  Hyponatremia is common after SAH, and there is evidence that it is associated with certain poorer outcomes. Larger, prospective studies are needed to assess these findings and provide further evidence.
authors.affiliation: Cerebrovascular Lab, Columbia University Medical Center, New York, New York, USA.
authors.forename: Ben
authors.initials: B
authors.lastname: Mapa
authors.affiliation: Cerebrovascular Lab, Columbia University Medical Center, New York, New York, USA; Department of Neurosurgery, Columbia University, New York, New York, USA. Electronic address: bet2110@cumc.columbia.edu.
authors.forename: Blake E S
authors.initials: BE
authors.lastname: Taylor
authors.affiliation: Cerebrovascular Lab, Columbia University Medical Center, New York, New York, USA; Department of Neurosurgery, Columbia University, New York, New York, USA.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Appelboom
authors.affiliation: Cerebrovascular Lab, Columbia University Medical Center, New York, New York, USA; Department of Neurosurgery, Columbia University, New York, New York, USA.
authors.forename: Eliza M
authors.initials: EM
authors.lastname: Bruce
authors.affiliation: Department of Neurology, Columbia University, New York, New York, USA; Neuro-intensive Care Unit, Columbia University, New York, New York, USA.
authors.forename: Jan
authors.initials: J
authors.lastname: Claassen
authors.affiliation: Cerebrovascular Lab, Columbia University Medical Center, New York, New York, USA; Department of Neurosurgery, Columbia University, New York, New York, USA; Department of Neurology, Columbia University, New York, New York, USA.
authors.forename: E Sander
authors.initials: ES
authors.lastname: Connolly
mesh_terms: D002423:Cause of Death; D004185:Disability Evaluation; D006801:Humans; D007010:Hyponatremia / Q000150:complications* / Q000401:mortality*; D002532:Intracranial Aneurysm / Q000150:complications* / Q000401:mortality*; D007902:Length of Stay; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000401:mortality*; D016019:Survival Analysis
keywords: Cerebral salt wasting syndrome; Hemorrhagic stroke; Hyponatremia; Subarachnoid hemorrhage; syndrome of inappropriate anti-diuretic hormone secretion