[Hyponatremia: from physiopathology to practice].

Area of Science:

• Internal Medicine
• Nephrology
• Endocrinology

Context:

• Hypotonic hyponatremia is the most frequent electrolyte disorder in hospitalized patients, often asymptomatic but linked to significant morbidity and mortality.
• Effective management hinges on a systematic, physiology-based approach to identify the underlying cause and assess hyponatremia's chronicity.

Purpose:

• To outline a systematic approach for diagnosing the causes of hypotonic hyponatremia.
• To guide the appropriate management strategies based on the etiology and chronicity of hyponatremia.

Summary:

• The diagnostic process involves documenting hypotonicity, assessing renal response and extracellular volume, and excluding hypocortisolism and hypothyroidism.
• Treatment strategies vary from isotonic saline for dehydration to cautious correction of chronic hyponatremia to prevent osmotic demyelination syndrome.
• Vasopressin receptor antagonists (vaptans) represent a promising therapeutic development, though further research on their impact is needed.

Impact:

• Provides a framework for clinicians to systematically diagnose and manage hypotonic hyponatremia, potentially reducing associated mortality and morbidity.
• Highlights the importance of differentiating acute from chronic hyponatremia to guide safe and effective therapeutic interventions.
• Underscores the evolving therapeutic landscape with the introduction of vaptans, emphasizing the need for ongoing research into their clinical utility.