Treatment of Severe Hyponatraemia: Serum Sodium <120 mmol/L or Symptomatic Presentation
Clinical Scenario
This protocol addresses patients with severe hyponatraemia (serum sodium below 120 mmol/L) or those presenting with neurological symptoms attributable to low sodium, regardless of the absolute level.
Serum Na <120 mmol/L
Drowsiness
Headache
Seizures
Treatment Approach
This is a medical emergency. Management requires an intensive care or high-dependency setting and centres on a hypertonic sodium preparation together with airway assessment — the complete treatment algorithm is in the full protocol.
Key Correction Goal
Sodium must be corrected at a carefully controlled rate. The protocol specifies the maximum safe rise in serum sodium over 24 hours to prevent overcorrection.
References
- HYPOnatraemia (Mild: 135–131 mmol/L, Moderate: 130–120 mmol/L, Severe: less than 120 mmol/L)
- Severe or symptomatic hyponatraemia (e.g. drowsiness, headache, seizures)
- Medical emergency – consider management in an intensive care/high dependency setting. Hypertonic saline and airway management may be indicated.
- 3% sodium chloride (hypertonic) requires careful consideration; seek senior advice if required.
- Correction should occur slowly – generally no more than 8 mmol/L in 24 hours.