Assessment of hyponatraemia

Last reviewed: 16 Apr 2025
Last updated: 29 Nov 2024

Summary

Differentials

Common

  • Hypotonic replacement of excess fluid loss
  • Drug-induced
  • Chronic kidney disease
  • Acute kidney injury
  • Congestive heart failure
  • Cirrhosis
  • Hyperglycaemia
  • Psychogenic polydipsia
  • Intracranial surgery
  • Head injury
  • Small cell lung cancer (SCLC)
  • Irrigation of operative field
  • Artifact in multiple myeloma
Full details

Uncommon

  • Potomania
  • Nephrotic syndrome
  • Salt-wasting nephropathy
  • Mineralocorticoid deficiency
  • Idiopathic syndrome of inappropriate antidiuretic hormone secretion (SIADH)
  • Stroke
  • Subarachnoid haemorrhage
  • Meningitis
  • Brain abscess
  • Lymphoma
  • Cervical cancer
  • Leukaemia
  • Central nervous system tumours
  • Pancreatic cancer
  • Pneumonia
  • Lung abscess
  • COPD
  • Cystic fibrosis
  • Positive-pressure ventilation
  • Artifact in hypertriglyceridaemia
Full details

Contributors

Authors

Ghania Masri, MD

Associate Professor of Medicine

University of Florida

College of Medicine Jacksonville

Jacksonville

FL

Disclosures

GM declares that she has no competing interests.

Peer reviewers

Judith Veis, MD

Section Director, Nephrology

Medstar Washington Hospital Center

Washington DC

Disclosures

JV declares that she has no competing interests.

Sean M. Bagshaw, FRCPC

Consultant Intensivist

Assistant Professor

University of Alberta Hospital

Alberta

Canada

Disclosures

SMB declares that he has no competing interests.

Laurie Solomon, MD FRCP

Consultant Nephrologist

Renal Unit

Lancashire Teaching Hospitals

Fulwood

Preston

UK

Disclosures

LS declares that he has no competing interests.

James W. Lohr, MD

Professor of Medicine

Veterans Hospital

Buffalo

NY

Disclosures

JWL declares that he has no competing interests.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

Spasovski G, Vanholder R, Allolio B, et al; Hyponatraemia Guideline Development Group. Clinical practice guideline on diagnosis and treatment of hyponatraemia. Eur J Endocrinol. 2014 Feb 25;170(3):G1-47.Full text  Abstract

Grant P, Ayuk J, Bouloux PM, et al. The diagnosis and management of inpatient hyponatraemia and SIADH. Eur J Clin Invest. 2015 Aug;45(8):888-94.Full text  Abstract

Verbalis JG, Goldsmith SR, Greenberg A, et al. Diagnosis, evaluation, and treatment of hyponatremia: expert panel recommendations. Am J Med. 2013 Oct;126(10 suppl 1):S1-42.Full text  Abstract

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.
  • Assessment of hyponatraemia images
  • Guidelines

    • Approach to hyponatremia according to the clinical setting
    • Emergency management of severe symptomatic hyponatraemia in adult patients
    More Guidelines
  • Patient information

    Hyponatraemia (low blood sodium)

    More Patient information
  • Calculators

    Osmolality Estimator (serum)

    Osmolal Gap Calculator (SI units)

    More Calculators
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