Hyponatraemia: mainly chronic and caused by drugs and SIADH.

Clinical bottom line (level 4)

  1. The commonest causes of severe symptomatic hyponatraemia were chronic ones such as diuretics, SIADH and oedematous disorders. Acute hyponatraemia was much less common and was often due to parenteral fluids, or polydipsia.
  2. Around 8% of patients died, and 10% developed neurological sequelae.
Sterns : Annals of Internal Medicine 1987; 107 (5): 656-664
Expires July 2005

The study

Case series with ?objective ?blinded outcomes, not adjusted for confounding factors, not validated in an independent set of patients.

Setting: two university hospitals, USA

62 patients (aged ?, ?% male) with 64 episodes of severe hyponatraemia (Na <110 mol/l)

Excluded if
  • isolated value




    • 100% followed for until discharge
    Outcomes studied:
  • mortality
  • neurological sequelae
  • cause: acute
  • cause: parenteral fluids and SIADH
  • cause: psychotic polydipsia
  • cause: Addison disease
  • cause: chronic
  • cause: diuretic agents only
  • cause: SIADH
  • cause: oedematous disorders
  • cause: Addison disease
  • cause: chronic renal failure

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    mortality until discharge 5/62 8.1%
    (1.3% to 15%)
    neurological sequelae until discharge 7/62 11%
    (3.4% to 19%)
    cause: acute until discharge 10/64 16%
    (6.7% to 25%)
    cause: parenteral fluids and SIADH until discharge 5/64 7.8%
    (1.2% to 14%)
    cause: psychotic polydipsia until discharge 4/64 6.3%
    (0.32% to 12%)
    cause: Addison disease until discharge 1/64 1.6%
    (0.0% to 4.6%)
    cause: chronic until discharge 54/64 85%
    (75% to 93%)
    cause: diuretic agents only until discharge 23/64 36%
    (24% to 48%)
    cause: SIADH until discharge 18/64 28%
    (17% to 39%)
    cause: oedematous disorders until discharge 9/64 14%
    (5.5% to 23%)
    cause: Addison disease until discharge 3/64 4.7%
    (0.0% to 9.9%)
    cause: chronic renal failure until discharge 1/64 1.6%
    (0.0% to 4.6%)

    • Only one death was due to central pontine myelinolysis- all other cases could be attributed to the patient's underlying disease.

    Comments

    1. Not enough data is given to determine the effect of speed of correction on subsequent outcome.

    Citation

    1. Sterns RH, : Severe symptomatic hyponatremia: treatment and outcome; a study of 64 cases. Annals of Internal Medicine 1987; 107 (5): 656-664
    Search Terms: hyponatrem* in Medline
    Contributor: Chris Ball and Clare Wotton, July 2000
    Reviewer:

    Clinical Question.
    Patient hyponatraemia
    Intervention or Exposure prevalence
    Outcome different causes, mortality and neurological sequelae