title: Serum sodium abnormalities during nonexertional heatstroke: incidence and prognostic values.
abstract: BACKGROUND
  Although heatstroke is often associated with dehydration, the clinical significance of serum sodium abnormalities in patients with heat-related illness during heat wave has been poorly documented.
  
  
  METHODS
  We evaluated 1263 patients (age, 82±15 years; body temperature, 40.1°C+1.2°C) admitted to emergency departments during the August 2003 heat wave in Paris, having a core temperature greater than 38.5°C and measurement of serum sodium concentrations. Patients were classified according to our previously described risk score of death.
  
  
  RESULTS
  Hyponatremia (<135 mmol/L) was reported in 409 (32%) and hypernatremia (>145 mmol/L) in 220 patients (17%). One-year survival was significantly decreased in patients with hypernatremia (45%; P=.004) but not in those with hyponatremia (58%; P=.86) as compared with patients with serum sodium concentration in the reference range (57%). Using Cox regression, only hypernatremia was an independent prognostic factor (hazard ratio, 1.35; 95% confidence interval, 1.09-1.36) when risk score was taken into account. Using logistic regression, 2 variables were independently associated with hyponatremia (heatstroke severity score and blood urea nitrogen-creatinine ratio<100). Conversely, 5 variables were independently associated with hypernatremia (living in an institution, dementia, serum creatinine>120 μmol/L, a blood urea nitrogen-creatinine ratio >100, and absence of long-term diuretic intake).
  
  
  CONCLUSIONS
  Serum sodium abnormalities are frequently observed in patients with a nonexertional heatstroke during heat wave; however, only hypernatremia should be considered as an independent risk factor of death. Rapid measurement of serum sodium concentration is mandatory to appropriately guide electrolyte resuscitation.
authors.affiliation: Emergency Department, Centre Hospitalo-Universitaire Pitié-Salpêtrière, Assistance-Publique Hôpitaux de Paris, Paris, and UPMC Univ Paris 06 France. pierre.hausfater@psl.aphp.fr
authors.forename: Pierre
authors.initials: P
authors.lastname: Hausfater
authors.forename: Bruno
authors.initials: B
authors.lastname: Mégarbane
authors.forename: Laurent
authors.initials: L
authors.lastname: Fabricatore
authors.forename: Sandrine
authors.initials: S
authors.lastname: Dautheville
authors.forename: Anabela
authors.initials: A
authors.lastname: Patzak
authors.forename: Marc
authors.initials: M
authors.lastname: Andronikof
authors.forename: Aline
authors.initials: A
authors.lastname: Santin
authors.forename: Gérald
authors.initials: G
authors.lastname: Kierzek
authors.forename: Benoît
authors.initials: B
authors.lastname: Doumenc
authors.forename: Christophe
authors.initials: C
authors.lastname: Leroy
authors.forename: Jafar
authors.initials: J
authors.lastname: Manamani
authors.forename: Florence
authors.initials: F
authors.lastname: Peviriéri
authors.forename: Bruno
authors.initials: B
authors.lastname: Riou
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D018883:Heat Stroke / Q000097:blood* / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology; D006801:Humans; D006955:Hypernatremia / Q000097:blood / Q000150:complications / Q000503:physiopathology; D007010:Hyponatremia / Q000097:blood / Q000150:complications / Q000503:physiopathology; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D012307:Risk Factors; D012964:Sodium / Q000097:blood* / Q000502:physiology
chemical_list: D012964:Sodium