title: Characteristics, symptoms, and outcome of severe dysnatremias present on hospital admission.
abstract: OBJECTIVE
  Dysnatremias are common in critically ill patients and associated with adverse outcomes, but their incidence, nature, and treatment rarely have been studied systematically in the population presenting to the emergency department. We conducted a study in patients presenting to the emergency department of the University of Bern.
  
  
  METHODS
  In this retrospective case series at a university hospital in Switzerland, 77,847 patients admitted to the emergency department between April 1, 2008, and March 31, 2011, were included. Serum sodium was measured in 43,911 of these patients. Severe hyponatremia was defined as less than 121 mmol/L, and severe hypernatremia was defined as less than 149 mmol/L.
  
  
  RESULTS
  Hypernatremia (sodium>145 mmol/L) was present in 2% of patients, and hyponatremia (sodium<135 mmol/L) was present in 10% of patients. A total of 74 patients had severe hypernatremia, and 168 patients had severe hyponatremia. Some 38% of patients with severe hypernatremia and 64% of patients with hyponatremia had neurologic symptoms. The occurrence of symptoms was related to the absolute elevation of serum sodium. Somnolence and disorientation were the leading symptoms in hypernatremic patients, and nausea, falls, and weakness were the leading symptoms in hyponatremic patients. The rate of correction did not differ between symptomatic and asymptomatic patients. Patients with symptomatic hypernatremia showed a further increase in serum sodium concentration during the first 24 hours after admission. Corrective measures were not taken in 18% of hypernatremic patients and 4% of hyponatremic patients.
  
  
  CONCLUSIONS
  Dysnatremias are common in the emergency department. Hyponatremia and hypernatremia have different symptoms. Contrary to recommendations, serum sodium is not corrected more rapidly in symptomatic patients.
authors.affiliation: Department of Nephrology and Hypertension, Inselspital, University of Bern, Switzerland.
authors.forename: Spyridon
authors.initials: S
authors.lastname: Arampatzis
authors.forename: Bettina
authors.initials: B
authors.lastname: Frauchiger
authors.forename: Georg-Martin
authors.initials: GM
authors.lastname: Fiedler
authors.forename: Alexander Benedikt
authors.initials: AB
authors.lastname: Leichtle
authors.forename: Daniela
authors.initials: D
authors.lastname: Buhl
authors.forename: Christoph
authors.initials: C
authors.lastname: Schwarz
authors.forename: Georg-Christian
authors.initials: GC
authors.lastname: Funk
authors.forename: Heinz
authors.initials: H
authors.lastname: Zimmermann
authors.forename: Aristomenis K
authors.initials: AK
authors.lastname: Exadaktylos
authors.forename: Gregor
authors.initials: G
authors.lastname: Lindner
mesh_terms: D004636:Emergency Service, Hospital; D005260:Female; D006760:Hospitalization; D006801:Humans; D006955:Hypernatremia / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D007010:Hyponatremia / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D015994:Incidence; D008297:Male; D012189:Retrospective Studies; D012964:Sodium / Q000097:blood*; D013557:Switzerland
chemical_list: D012964:Sodium