How should I manage a patient with mild hypokalaemia (K+ 3.0-3.5 mmol/L) without significant symptoms?

For an asymptomatic patient with mild hypokalaemia (potassium level 3.0-3.5 mmol/L), management in primary care includes the following steps:

• Confirm the potassium level by repeating the serum potassium measurement to exclude spurious results and to check for any rapid decline in potassium concentration.
• Identify and treat any underlying cause such as acute illness or medication contributing to potassium loss. If a causative medication (e.g., thiazide or loop diuretics) is identified, consider stopping it if appropriate or switching to potassium-sparing diuretics like amiloride, spironolactone, or eplerenone, and recheck potassium after 2 weeks or sooner based on clinical judgement.
• Oral potassium supplementation with potassium chloride is recommended to replenish potassium stores, aiming to raise serum potassium above 3.5 mmol/L in healthy individuals and to at least 4.0 mmol/L in those with cardiovascular risk factors.
• Monitor for hypomagnesaemia as concurrent magnesium deficiency can impair correction of hypokalaemia; correct magnesium if low, preferably with oral supplementation in mild cases.
• Encourage dietary potassium intake through foods such as tomatoes, green leafy vegetables, potatoes, nuts, legumes, and fruits like bananas and oranges, although dietary changes alone are insufficient if losses continue.
• Reassess serum potassium approximately 2 weeks after intervention or sooner if clinically indicated to ensure correction and to guide further management.
• Refer to an endocrinologist or specialist if oral potassium is not tolerated, if hypokalaemia persists despite treatment, or if the cause remains unclear.

This approach aims to prevent potential cardiac and neuromuscular complications by safely restoring potassium levels while addressing the underlying cause.