What is the recommended management for an asymptomatic 67‑year‑old woman with serum potassium 5.7 mmol/L (no chest pain or dyspnoea) according to NICE CKS guidelines?

Management of Asymptomatic Hyperkalemia (K⁺ 5.7 mmol/L)

For an asymptomatic 67-year-old woman with serum potassium 5.7 mmol/L and no ECG changes, you should immediately implement dietary potassium restriction, review and adjust any RAAS inhibitors or potassium-sparing medications, obtain an ECG to confirm absence of cardiac effects, and recheck potassium within 24–48 hours—this level represents moderate hyperkalemia requiring prompt intervention but not emergency treatment. 1

Immediate Assessment (Within Hours)

• Obtain a 12-lead ECG immediately to assess for peaked T waves, flattened P waves, prolonged PR interval, or widened QRS complex, as these findings would mandate urgent treatment even in asymptomatic patients 1
• Confirm the result is not pseudohyperkalemia by ensuring proper blood sampling technique (no prolonged tourniquet, no fist clenching, no hemolysis) 1
• A potassium level of 5.7 mmol/L falls into the moderate hyperkalemia category (5.5–6.0 mmol/L) and requires attention but not immediate emergency intervention if the patient remains asymptomatic and the ECG is normal 1, 2

Medication Review and Adjustment

• If the patient is taking mineralocorticoid receptor antagonists (MRAs), reduce the dose by 50% immediately when potassium exceeds 5.5 mmol/L 1, 2
• Review all medications that may contribute to hyperkalemia: ACE inhibitors, ARBs, NSAIDs, potassium-sparing diuretics, and potassium supplements 1
• Do not discontinue RAAS inhibitors unless potassium exceeds 6.0 mmol/L or ECG changes develop, as premature discontinuation removes proven mortality and morbidity benefits in heart failure and chronic kidney disease 1
• Consider dose reduction of RAAS inhibitors by 50% rather than complete discontinuation if potassium approaches 6.0 mmol/L 1

Dietary Intervention

• Restrict dietary potassium intake to <3 g/day (approximately 50–70 mmol/day) 1
• Counsel the patient to avoid high-potassium foods: bananas, oranges, melons, potatoes, tomato products, salt substitutes containing potassium chloride, legumes, lentils, chocolate, and yogurt 1
• Avoid herbal supplements that can raise potassium levels, including alfalfa, dandelion, horsetail, Lily of the Valley, milkweed, and nettle 1

Pharmacologic Management (If Needed)

• If the patient has adequate kidney function, consider loop diuretics (furosemide 40–80 mg) to enhance urinary potassium excretion 1
• For patients requiring continued RAAS inhibitor therapy, consider newer potassium binders (patiromer 8.4 g once daily or sodium zirconium cyclosilicate 10 g three times daily for 48 hours) to maintain cardioprotective medications 1
• Avoid sodium polystyrene sulfonate (Kayexalate) for chronic management due to risk of intestinal ischemia and colonic necrosis 1

Monitoring Protocol

• Recheck serum potassium within 24–48 hours to assess response to initial interventions 1
• Schedule additional follow-up potassium measurement within 1 week 1
• If on RAAS inhibitors, monitor potassium levels within 1 week after any dose adjustment 1
• Establish ongoing monitoring based on comorbidities (CKD, diabetes, heart failure) and medication regimen, typically monthly for the first 3 months, then every 3–6 months 1

Assess Underlying Conditions

• Evaluate for chronic kidney disease (check creatinine and eGFR), as impaired renal function is a major contributor to hyperkalemia 1
• Assess for diabetes mellitus, heart failure, and adrenal insufficiency, as these conditions markedly increase hyperkalemia risk 1
• Investigate non-dietary causes: metabolic acidosis, tissue destruction, constipation, and inadequate dialysis in dialysis-dependent patients 1

Escalation Criteria (When to Refer Urgently)

• Immediate hospital referral is indicated if:
  • ECG changes develop (peaked T waves, absent P waves, prolonged PR, widened QRS, sine-wave pattern) 1
  • Patient develops symptoms (muscle weakness, paresthesias, palpitations) 1
  • Potassium rises above 6.0 mmol/L on repeat testing 1
  • Rapid deterioration of kidney function occurs 1

Target Potassium Range

• Aim to maintain serum potassium between 4.0–5.0 mmol/L, as levels >5.0 mmol/L are associated with increased mortality risk, especially in patients with comorbidities such as heart failure, chronic kidney disease, or diabetes mellitus 1, 2
• Recent evidence suggests maintaining potassium ≤5.0 mmol/L may be safer than the traditional upper limit of 5.5 mmol/L 2

Common Pitfalls to Avoid

• Do not ignore the need for repeat potassium measurement to confirm hyperkalemia and monitor treatment response 1
• Do not prematurely discontinue beneficial RAAS inhibitors due to moderate hyperkalemia; dose reduction and addition of potassium binders is preferred to maintain cardioprotective and renoprotective benefits 1
• Do not overlook potential pseudohyperkalemia from poor phlebotomy technique or delayed sample processing 1
• Do not fail to check and correct magnesium levels if hypokalemia develops during treatment, as hypomagnesemia makes hypokalemia resistant to correction 1

Special Considerations for High-Risk Populations

• Patients with heart failure: Both hyperkalemia and hypokalemia increase mortality risk; strict maintenance of potassium 4.0–5.0 mmol/L is crucial 1, 3
• Patients with chronic kidney disease: Compensatory mechanisms may provide some tolerance to elevated potassium, but intervention is still warranted at 5.7 mmol/L 1
• Patients with diabetes: Higher mortality risk at any given potassium level; require more aggressive monitoring (every 2–4 weeks initially) 1