5th April 2024

Management

Management depends on the cause, and where hyponatremia is due to congestive cardiac failure with a hypervolemic fluid status, fluid restriction and diuretics are used. 

Hyponatraemia secondary to gastrointestinal losses will require fluid replacement with 0.9% sodium chloride. 

In SIADH related hyponatremia, treating the cause; fluid restriction and medications such as tolvaptan and demeclocycline are used.   

In severe symptomatic hyponatremia, emergency correction using 150 ml of 1.8% or 3% sodium chloride over 20 minutes is used, with frequent sodium monitoring. The aim is to increase sodium concentration by 4-6 mmol in 24 hours and once stable, correction is slowed, aiming to increase sodium by 10 mmol in 24 hours. 

Osmotic demyelination syndrome 

Correcting hyponatremia too quickly can cause rapid changes in osmolality and disrupt the blood brain barrier. This is toxic to and causes damage to the myelin sheath. Presentation includes progressive neurological deficits and weakness; behavioural changes, encephalopathy, quadriplegia and locked in syndrome.