Hyponatraemia Correction Pathway • MEDiscuss

Hyponatraemia Correction Pathway v1.0 Adrogue-Madias Kinetics, Deficit Synthesis & ODS Prevention

⚠ The ODS Speed Limit: Rapid correction of chronic hyponatraemia causes irreversible Osmotic Demyelination Syndrome (ODS). This engine strictly enforces an absolute maximum correction limit of 8 mEq/L per 24 hours (or 6 mEq/L for high-risk patients).

1 Patient Baseline

Age (yrs)

Biological Sex

Weight (kg)

Current Serum Na⁺ (mEq/L)

Neurological Symptoms

2 Aetiology & Risk Modifiers

Clinical Volume Status

High Risk for ODS present?
Check if: Severe Malnutrition, Alcoholism, Advanced Liver Disease, Hypokalaemia, or Serum Na⁺ < 105.
(Restricts max 24h correction to 6 mEq/L).

3 Infusate Selection

📚 Algorithm Architecture & TrapsThe Absolute Limits of Correction

Standard Risk: Maximum increase of 8 mEq/L in any 24-hour period.
High Risk for ODS: Maximum increase of 6 mEq/L in any 24-hour period. (Applies to severe malnutrition, alcoholism, advanced liver disease, hypokalaemia, or baseline Na < 105).

⚠ The Hypervolaemia Trap

In hypervolaemic hyponatraemia (e.g., congestive heart failure, cirrhosis), total body sodium is actually elevated, but total body water is elevated even more. Administering continuous hypertonic saline drips to these patients will trigger catastrophic flash pulmonary oedema. Management requires fluid restriction and loop diuretics. 3% Saline is reserved exclusively as a small, emergency bolus for active seizures.

Adrogue-Madias Formula

Calculates the expected change in serum Na⁺ after administering 1 Litre of a specific infusate.
$\Delta$Na⁺ = (Infusate Na⁺ – Serum Na⁺) / (Total Body Water + 1)

Infusate Sodium Concentrations

IV Fluid	Na⁺ Content (mEq/L)
3% Hypertonic Saline	513
1.6% Hypertonic Saline	274
0.9% Normal Saline	154
Lactated Ringer’s	130

Abbreviations: Na⁺ (Sodium) · ODS (Osmotic Demyelination Syndrome) · TBW (Total Body Water) · SIADH (Syndrome of Inappropriate Antidiuretic Hormone) · D5W (5% Dextrose in Water)

⚠ Clinical Disclaimer: These algorithms are clinical decision aids. The Adrogue-Madias formula provides an estimate and does not account for concurrent fluid losses, insensible losses, or auto-diuresis. Frequent laboratory monitoring (Q2-4H) is absolutely mandated during active hypertonic correction.

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Algorithm References & Evidence Base

Adrogué HJ, Madias NE. Hyponatremia. N Engl J Med. 2000;342(21):1581-1589.
Spasovski G, et al. Clinical practice guideline on diagnosis and treatment of hyponatraemia. Eur J Endocrinol. 2014;170(3):G1-47.
Sterns RH. Disorders of Plasma Sodium – Causes, Consequences, and Correction. N Engl J Med. 2015;372(1):55-65.

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