title: Hyponatremia-induced change in mood mimicking late-onset bipolar disorder.
abstract: OBJECTIVE
  Hyponatremia and bipolar disorder are rarely considered to have common features. This report describes a case of hyponatremia secondary to syndrome of inappropriate antidiuretic hormone secretion (SIADH) presenting as late-onset bipolar disorder and discusses the evidence linking hyponatremia to mood disorders.
  
  
  METHODS
  Case report and review of published literature.
  
  
  RESULTS
  This case provides evidence that mood changes identical to those seen in bipolar disorder may be caused by hyponatremia at a variety of concentrations.
  
  
  CONCLUSIONS
  Further research is required to determine causes of SIADH in psychiatric patients with symptomatic hyponatremia and to elucidate the mechanism by which hyponatremia causes changes in mood. In older patients presenting with new-onset bipolar disorder, a physical etiology must always be excluded.
authors.affiliation: Department of Psychiatry, Warneford Hospital, University of Oxford, Warneford Lane, OX3 7JX Oxford, UK. rebecca.mcknight@psych.ox.ac.uk
authors.forename: Rebecca F
authors.initials: RF
authors.lastname: McKnight
authors.forename: Simon
authors.initials: S
authors.lastname: Hampson
mesh_terms: D017668:Age of Onset; D000368:Aged; D001714:Bipolar Disorder / Q000503:physiopathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000150:complications*; D019964:Mood Disorders / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology