title: Lithium-induced nephrogenic diabetes insipidus in older people.
abstract: METHODS
  We report two patients. The first is a 68-year-old woman who presented with a 2-day history of vomiting. She was hypernatraemic and her elevated serum sodium concentration did not improve initially, despite adequate fluid replacement. She subsequently developed polyuria and polydipsia. The second patient, a 77-year-old woman, presented with delirium and severe hypernatraemia after being treated for a chest infection 1 week earlier. Both patients were on long-term lithium treatment.
  
  
  METHODS
  In both the cases, a supervised water-deprivation test done after normalization of the blood biochemistry showed partial nephrogenic diabetes insipidus.
  
  
  RESULTS
  Lithium was discontinued.
  
  
  CONCLUSIONS
  Older people on lithium-especially those requiring supportive care-are at risk of severe hypernatraemia after an acute illness or if their fluid intake is restricted.
authors.affiliation: Department of Integrated Medicine, Withybush General Hospital, Haverfordwest SA61 2PZ, UK.
authors.forename: D
authors.initials: D
authors.lastname: Mukhopadhyay
authors.forename: L
authors.initials: L
authors.lastname: Gokulkrishnan
authors.forename: K
authors.initials: K
authors.lastname: Mohanaruban
mesh_terms: D000368:Aged; D018500:Diabetes Insipidus, Nephrogenic / Q000139:chemically induced* / Q000628:therapy; D005260:Female; D006801:Humans; D008094:Lithium / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D008094:Lithium