The causes of hyperkalaemia can be placed into the five categories shown below:


  • Angiotensin converting enzyme inhibitors (ACEI)
  • Angiotensin receptor blockers
  • Non-steroidal anti inflammatories (NSAIDs)
  • Beta blockers
  • Suxamethonium
  • K+ supplementation
  • K+ sparing diuretics

Renal and metabolic diseases

  • Acute and chronic renal failure
  • type 4 renal tubular acidosis (resulting from aldosterone insufficiency or insensitivity)
  • Metabolic acidosis


  • Fasting – caused by a relative lack of insulin

Endocrine disorders

  • Addison’s disease
  • Hyporeninaemia
  • Insulin deficiency


  • Tumour lysis
  • Rhabdomyolysis
  • Massive transfusion
  • Massive haemolysis

Learning bite

Spurious hyperkalaemia can occur, particularly due to haemolysis from difficult venepuncture. If the potassium result doesn’t fit the clinical picture, it is important to repeat this, performing a blood gas if possible to get a rapid result. However, don’t wait for a repeat lab result to start managing the patient if the clinical picture fits.