Hyperkalaemia

High serum potassium; associated with cardiac arrhythmias

Aetiology

Conditions

  • Acute kidney injury
  • Chronic kidney disease
  • Rhabdomyolysis
  • Adrenal insufficiency
  • Tumour lysis syndrome

Medications

  • Aldosterone antagonists (spironolactone and eplerenone)
  • ACE inhibitors
  • Angiotensin II receptor blockers
  • NSAIDs
  • Potassium supplements

Clinical presentation

  • When present, the symptoms of hyperkalemia are nonspecific and predominantly related to muscular or cardiac function - fatigue, muscle weakness, palpatations/chest pain

Investigations

Bloods

  • U+Es - potassium, creatinine, urea, eGFR

ECG

  • Tall peaked T waves
  • Flattening or absence of P waves
  • Broad QRS complexes
notion image

Management

  • Cardiac monitor and IV access
  • Mainstay of treatment is with an insulin and dextrose infusion and IV calcium gluconate
    • 10 mls 10% calcium gluconate (2-3 mins) - protects myocardium
    • Insulin (actrapid 10 units) with 50mls 50% dextrose (30 mins) - moves K+ back into cells
  • Other options:
    • Salbutamol neb (90 mins) - temporarily drives potassium into cells
    • Sodium bicarbonate if acidotic
    • In chronic hyperkalaemia (not used in acute setting) - calcium resonuim to prevent absorption from GI tract
    • IV fluids can be used to increase urine output, which encourages potassium loss from the kidneys (but don’t fluid overload patients with renal failure)