How should I manage a patient with mild hypokalaemia who is asymptomatic?

Management of an asymptomatic patient with mild hypokalaemia (serum potassium 3.0–3.4 mmol/L) involves the following steps:

• Confirm the serum potassium measurement by repeating the test to exclude spurious hypokalaemia and to monitor for any rapid decline in potassium levels.
• Identify and treat any underlying causes such as acute illness or medication contributing to potassium loss. If a causative medication is identified, stop it if appropriate and recheck potassium after 2 weeks or sooner based on clinical judgement.
• Consider switching potassium-wasting diuretics (e.g., thiazides or frusemide) to potassium-sparing diuretics (e.g., amiloride, spironolactone, or eplerenone) if diuretics are implicated.
• Recommend increasing dietary potassium intake through foods such as tomatoes, green leafy vegetables, potatoes, nuts, seeds, legumes, and fruits like bananas and oranges, especially if poor diet is suspected.
• Consider oral potassium chloride supplementation to correct hypokalaemia, aiming for a serum potassium concentration >3.5 mmol/L in healthy individuals, with repeat serum potassium testing 3–4 days after starting supplementation to guide dosing.
• Assess for concurrent hypomagnesaemia, as correction of hypokalaemia may be ineffective without magnesium repletion. Manage mild hypomagnesaemia with oral magnesium supplements if present.
• Monitor the patient clinically and biochemically, repeating serum potassium after 2 weeks or sooner if clinically indicated.
• Refer to an endocrinologist if oral potassium supplementation is not tolerated, if the cause of hypokalaemia is unclear, or if potassium levels remain low despite treatment.

This approach aims to prevent progression to symptomatic or severe hypokalaemia and avoid potential cardiac complications.

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