What are the recommended management strategies for asymptomatic hyponatraemia in adults?

Recommended management strategies for asymptomatic hyponatraemia in adult patients include:

• Manage mild asymptomatic hyponatraemia (serum sodium 130–135 mmol/L) in primary care with repeat serum sodium measurement to exclude rapid decline, which would require hospital admission.
• Treat any acute illness that may contribute to hyponatraemia and recheck serum sodium after 2 weeks or sooner based on clinical judgement.
• Stop any medications that may cause hyponatraemia if appropriate, and recheck serum sodium after 2 weeks. If medication cannot be stopped, discuss with the relevant specialist for monitoring or referral.
• If serum sodium remains low after stopping causative medication, assess for other underlying causes or refer to an endocrinologist.
• Provide patient information on hyponatraemia to support understanding and self-management.
• For moderate asymptomatic hyponatraemia (serum sodium 125–129 mmol/L), consider specialist referral, especially if the cause is unclear or if SIADH or endocrine causes are suspected.
• In cases of hypervolaemia, fluid restriction is recommended to prevent further fluid overload.
• In hypovolaemia, restore extracellular volume with 0.9% saline infusion.
• For SIADH, fluid restriction is advised; if no clear cause is found, further imaging may be needed to exclude malignancy.

Overall, management focuses on identifying and treating underlying causes, stopping offending medications, monitoring serum sodium levels, and using fluid management strategies tailored to the patient's volume status, with referral to specialists when the cause is unclear or complex.

NICE CKS