Review Article

Sodium Balance and Imbalance: A Review Linking Physiology withPathophysiology

Samuel Sherng Young Wang1
Tan Tock Seng Hospital, Singapore
Haoming Tang2
Duke-NUS Medical School, Singapore
Wang Chin Eileen Ng2
Duke-NUS Medical School, Singapore
Yi Xin Li2
Duke-NUS Medical School, Singapore
Yu Theng Rachel Ho2
Duke-NUS Medical School, Singapore
Xiao Ran Luo2
Duke-NUS Medical School, Singapore
Muhammad M Javaid3
Monash Rural Health Mildura, Monash University, Victoria, Australia, South West Healthcare, Warrnambool, Victoria, Australia. Deakin School of Medicine, Deakin University, Warrnambool, Victoria, Australia

✉ Correspondence: Muhammad M Javaid Email: mmjavaid@doctors.org.uk

DOI https://doi.org/10.70302/jpsim.v6i4.2557
Volume: 6, Issue 4 Pages: 308–314 Published: 21 Nov 2025
Received: 26 May 2025 Revised: 22 Aug 2025 Accepted: 11 Oct 2025 Published Online: 21 Nov 2025

Abstract

Sodium (Na+), one of the major extracellular cations in the body, exerts a significant role in regulating body fluid compartments and generating action potentials. It represents one of the most important and readily available biomarkers of fluid status. Disturbances of Na+ homeostasis are frequently observed in outpatient and inpatient settings and can be challenging to clinicians attempting to decipher the underlying aetiologies. Various disorders involving the renal, endocrine, and central nervous systems can lead to dysnatremias and imbalance in volume status. Understanding the diverse physiological mechanisms involved in normal Na+ regulation and the expected pathological outcomes when the normal processes are disrupted is crucial in assisting clinicians with coming up with reasonable differential diagnoses and targeted management plans for Na+ disorders. This review summarises the pathophysiology of Na+ disorders by linking it closely with normal Na+ homeostasis.

Keywords
sodium hyponatraemia hypernatraemia physiology pathophysiology

How to Cite This Article

Wang SSY, Tang H, Ng WCE, Li YX, Ho YTR, Luo XR, et al.. Sodium Balance and Imbalance: A Review Linking Physiology withPathophysiology. J Pak Soc Intern Med. 2025;6(4):308–314. doi:10.70302/jpsim.v6i4.2557

⭳ Download PDF

Conflict of Interest

All authors declare no competing interests.

Disclosed in accordance with ICMJE and COPE guidelines.

Funding

No specific funding was received for this research.

Funder information follows the Crossref Funder Registry standard.

References

  1. Seay NW, Lehrich RW, Greenberg A. Diagnosis and management of disorders of body tonicity—hyponatremia and hypernatremia: core curriculum 2020. Am J Kidney Dis. 2020;75(2):272-86.
  2. Upadhyay A, Jaber BL, Madias NE.. Incidence and prevalence of hyponatremia. Am J Med. 2006;119(7 Suppl 1):S30-5.
  3. Yun G, Baek SH, Kim S. (2023). Evaluation and management of hypernatremia in adults: clinical perspectives. Korean J Intern Med. 2023;38(3):290-302.
  4. Voets P, Vogtländer, NPJ, Kaasjager KAH. Understanding dysnatremia. J Clin Monit Comput. 2021;35(3):655-59.
  5. Dhareshwar SS. Distribution of water in the body spaces. Encyclopedia of Human Nutrition. 4th ed. Volume 3. 2023; ISBN 978-0-12-375083-9.
  6. Bernal A, Zafra MA, Simón MJ, Mahía J. (2023). Sodium Homeostasis, a Balance Necessary for Life. Nutrients. 2023;15(2):395.
  7. Roumelioti ME, Glew RH, Khitan ZJ, Rondon-Berrios H, Argyropoulos CP, Malhotra D, et al. Fluid balance concepts in medicine: Principles and practice. World J Nephrol. 2018;7(1): 1-28.
  8. Knepper MA, Kwon TH, Nielsen S. Molecular physiology of water balance. N Engl J Med. 2015;372(14):1349-58.
  9. Su W, Cao R, Zhang XY, Guan Y. Aquaporins in the kidney: physiology and pathophysiology. Am J Physiol Renal Physiol. 2020;318(1):193-203.
  10. Boone M, Deen PMT. Physiology and pathophysiology of the vasopressin-regulated renal water reabsorption. Eu J Physiol. 2008;456(6): 1005–24.

Reference list indexed for Google Scholar and ResearchGate. DOI links resolve via doi.org.

CC BY CC BY 4.0 This article is published under the Creative Commons Attribution 4.0 International License. May be shared and adapted with attribution. © 2025 Journal of Pakistan Society of Internal Medicine.
📃 In This Issue View All
Review Article Thyroid Disorders in Pregnancy: Clinical Implications and Management Strategies Baig BI, Usman A Original Article Prevalence of Hypertension Among Urban Adults in Pakistan: A Cross-Sectional Study Khan TM, Ahmed S, Malik RA Original Article Serum Ferritin as a Prognostic Marker in COVID-19 Severity: A Hospital-Based Study Rehman N, Sheikh I, Javed K Original Article Comparison of Ultrasound-Guided versus Landmark-Based Central Venous Catheter Insertion Zafar S, Gillani SA Original Article Outcomes of Laparoscopic Cholecystectomy in Acute Cholecystitis: A Retrospective Analysis Raza SH, Butt N, Qureshi AM
👥 More by These Authors
Review Article Antibiotic Resistance Patterns in Community-Acquired Pneumonia: Emerging Trends Hussain I, Farooq Z Original Article Neonatal Sepsis: Bacteriological Profile and Antibiogram in a Tertiary Care Hospital Iqbal M, Rashid T Review Article Statin Therapy in Non-Alcoholic Fatty Liver Disease: A Systematic Review Nawaz F, Cheema HA, Mehmood Y Original Article Impact of Diabetes Mellitus on Post-Operative Wound Healing in General Surgery Siddiqui FA, Noor M, Akhtar W
🔗 Related Articles By Keywords
Original Article Serum Ferritin as a Prognostic Marker in COVID-19 Severity: A Hospital-Based Study Rehman N, Sheikh I, Javed K Original Article Comparison of Ultrasound-Guided versus Landmark-Based Central Venous Catheter Insertion Zafar S, Gillani SA Original Article Outcomes of Laparoscopic Cholecystectomy in Acute Cholecystitis: A Retrospective Analysis Raza SH, Butt N, Qureshi AM Original Article Cervical Cancer Screening Awareness Among Rural Women in Punjab Bibi S, Anjum R, Hassan F