Hyperkalaemia DDx


  • Hyperkalaemia is defined as serum potassium level > 5.5 mEq/L
  • Hyperkalaemia is potentially life-threatening due to the risk of cardiac dysrhythmias
  • Most patients begin to manifest significant ECG changes at serum levels > 6.5 mEq/L


Increased potassium intake (rare)

  • Oral (potassium supplements)
  • IV (transfusion of stored blood, supplement infusions)
  • Gastrointestinal hemorrhage

Increased release from tissues

  • Tissue injury
  • Rhabdomyolysis, tumour lysis syndrome
  • Burns, ischaemia, haemolysis
  • Intense physical activity
  • hyperthermia

Decreased renal excretion

  • Renal failure (acute and chronic)
  • Hypoaldosteronism, Addison’s, Chronic active hepatitis
  • Obstructive uropathy

Transcellular shift

  • Acidosis:
    • Metabolic acidosis (diabetic ketoacidosis, mineral acid overdose)
    • Respiratory acidosis

Factitious (Pseudo-hyperkalaemia)

  • Laboratory error
  • Haemolysis of sample, clenched fist, ischaemic tourniquet
  • Sample taken from IV running potassium-containing fluid
  • Leucocytosis, thrombocytosis

Drugs causing hyperkalaemia

  • Transcellular shift/ release from tissues
    • Suxamethonium, Beta blockers, phenylephrine
  • Aldosterone inhibition
    • ACE inhibitors, Angiotensin II blockers
    • Heparin, spironolactone, Beta blockers
  • Increased aldosterone resistance (Trimethoprim, amiloride)
    • Inhibition Na/K/ATPase (Digoxin)
  • Potassium supplements and IV additives (Increase exogenous potassium)

References and Links


CCC 700 6

Critical Care


Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of three amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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