Hyperkalaemia

Background

  • Assess severity
    • Mild – K+ 5.5-6.0 mmol/L
    • Possible emergency – K+ 6.1-6.9 mmol/L
    • Usually an emergency – K+ >7.0 mmol/L
      • Above needs to be taken into context, if sudden rise with AKI, more likely to be significant
  • Symptoms
    • Arrhythmias
    • Muscle weakness, paraesthesia, fatigue
  • ECG changes
    • peaked T waves, widening QRS complex
  • Causes
    • Pseudohyperkalaemia
      • contamination from FBC tube, delayed arrival of specimen at lab, storage at low tempreatures, leakage from platelets, difficult sample collection
    • Medications
      • ACE, ARB
      • Potassium supplements
      • Potassium sparing diuretics – spironolactone, amiloride
      • NSAIDs
      • Trimethoprim
      • Heparin
      • Beta blockers
    • AKI/CKD (usually stage 4+)
    • Diabetic nephropathy

 

Data gathering

  • Red flags – muscle weakness, paralysis, paraesthesia, fatigue
  • Others – medications, passing urine

 

Clinical management

  • K+ 5.5 – 5.9
    • Repeat K+ within 1-2 weeks
    • Review medications, renal function
    • Take more seriously if
      • sudden decrease in eGFR
      • rise > 0.5 mmol/L
  • K+ 6.0 – 7.0
    • Recheck as soon as possible
    • Stop contributing medications
    • ECG
    • Consider referral to AAU (not A+E) depending on:
      • clinical state of patient
      • arrhythmia
      • muscle weakness, paralysis, paraesthesia, fatigue
      • ECG changes
      • rapid fall in eGFR
      • rapid increase in potassium (>0.5 mmol/L within 2 weeks)
  • K+ 7.0
    • refer to hospital (avoid A+E unless acutely unwell)