title: The pattern of plasma sodium abnormalities in an acute elderly care ward: a cross-sectional study.
abstract: BACKGROUND
  The combination of ageing, illness, and medications can lead to hyponatraemia or hypernatraemia.
  
  
  OBJECTIVE
  To describe the distribution of plasma sodium levels in older patients admitted to hospital.
  
  
  METHODS
  We carried out a hospital based cross-sectional study examining 1,511 serum sodium concentrations ([Na+]) among 336 elderly patients and attempted to elucidate the cause(s) of the abnormal serum [Na+].
  
  
  RESULTS
  The study population had a mean age of 81.4. Ninety-two (27.4%) patients had hyponatraemia and seven patients (2.1%) had hypernatraemia during their hospitalisation. The distribution of [Na+] results was towards the lower end of the normal range. The mortality rate of patients with hyponatraemia was 14.1% and that of patients with normal serum [Na+] was 8.9%. Six patients with hypernatraemia died in hospital. Lower respiratory tract infection and medication accounted for the majority of cases.
  
  
  CONCLUSIONS
  Deranged [Na+] is common among elderly patients admitted to hospital.
authors.affiliation: South Munster Geriatric Training Scheme, Dept of Geriatric Medicine, Cork University Hospital, Wilton, Cork.
authors.forename: K A
authors.initials: KA
authors.lastname: O'Connor
authors.forename: P E
authors.initials: PE
authors.lastname: Cotter
authors.forename: M
authors.initials: M
authors.lastname: Kingston
authors.forename: C
authors.initials: C
authors.lastname: Twomey
authors.forename: D
authors.initials: D
authors.lastname: O'Mahony
mesh_terms: D000208:Acute Disease; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D006760:Hospitalization; D006801:Humans; D006955:Hypernatremia / Q000097:blood* / Q000453:epidemiology / Q000209:etiology; D007010:Hyponatremia / Q000097:blood* / Q000453:epidemiology / Q000209:etiology; D007494:Ireland / Q000453:epidemiology; D015995:Prevalence; D012964:Sodium / Q000097:blood*
chemical_list: D012964:Sodium