Renal Emergency Medicine A

Hyponatraemia Severity & Correction Rate

Classifies hyponatraemia severity and guides safe correction rate. Maximum correction: 10 mmol/L in 24 hours (6–8 mmol/L in high-risk patients) to prevent osmotic demyelination syndrome (ODS).

Used in: Hyponatraemia

Score interpretation

Mild Hyponatraemia (130–135 mmol/L) 130–134

Mild hyponatraemia. Usually asymptomatic.

→ Identify and treat cause (SIADH, hypothyroidism, diuretics, heart failure, cirrhosis). Fluid restriction if SIADH. Monitor Na⁺ every 24–48 hours.

Moderate Hyponatraemia (125–129 mmol/L) 125–129

Moderate hyponatraemia.

→ Identify cause. Treat underlying condition. Fluid restriction ±vasopressin antagonist (tolvaptan) for refractory SIADH. Monitor 12-hourly.

Severe Hyponatraemia (<125 mmol/L) 100–124

Severe hyponatraemia — high risk of osmotic demyelination syndrome (ODS) if corrected too rapidly.

→ Correct at ≤10 mmol/L per 24 hours (max 6–8 mmol/L if chronic/high ODS risk). For SEVERE SYMPTOMS: hypertonic saline (3% NaCl) 150 mL IV over 20 min. Target: raise Na⁺ by 5 mmol/L. Repeat if needed. ICU care if severe symptoms.

Interpretation bands for the Hyponatraemia. Apply clinical judgement and local guidance.

References

Spasovski G et al. Clinical practice guideline on diagnosis and treatment of hyponatraemia. Eur J Endocrinol. 2014;170(3):G1-G47.
Verbalis JG et al. Diagnosis, evaluation, and treatment of hyponatremia: expert panel recommendations. Am J Med. 2013;126(10 Suppl 1):S1-42.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Drugs

Pathways

Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.

Score interpretation

References

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