Potassium supplements (oral [PO] or intravenous [IV])
Massive blood transfusion
Release from intracellular fluid (ICF)
Rhabdomyolysis
Burns
Crush injury
Tumour lysis syndrome
Haemoylsis
Acidosis
Insulin deficiency
Beta-blockers
Digoxin
Suxamethonium
Inadequate excretion
Renal impairment
Acute kidney injury (AKI)
Chronic kidney disease (CKD)
Medications
Angiotensin converting enzyme inhibitors (ACEIs)
Angiotensin receptor blockers (ARBs)
Non-steroidal anti-inflammatory drugs (NSAIDs)
Potassium-sparring diuretics
Aldosterone deficiency eg Addison’s disease
Pseudohyperkalaemia
Laboratory artefact typically caused by haemolysis during venepuncture
Presentation of hyperkalaemia
Asymptomatic
Nausea and vomiting
Diarrhoea
Hypotonia
Muscle weakness
Hyporeflexia
Paraesthesia
Cardiac arrhythmias
Investigation of hyperkalaemia
Urea & electrolytes (U&Es)
Venous blood gas (VBG)
Whole blood potassium (WBK)
Electrocardiogram (ECG) changes include
Classical changes – occurring in this order:
1. Flattened P waves
2. Tall tented T waves
3. Wide QRS becoming sinusoidal
Full list of changes
Flattened P waves
Prolonged PR interval (first degree heart block)
Prolonged QRS interval
Shortened QT interval
ST segment depression
Tall tented T waves
Sinusoidal QRST
Bradycardia
Pulsed monomorphic ventricular tachycardia (VT)
Initial management of hyperkalaemia
If potassium concentration ≤6.5 mM and no ECG changes are present, verify hyperkalaemia
U&Es: may be falsely elevated by haemolysis; consider sending a repeat U&Es accompanied by a WBK before commencing treatment
VBG: there is often a significant discrepancy between potassium concentration on VBG and U&Es; consider waiting for formal U&Es to come back before commencing treatment
If potassium concentration >6.5 mM and/or ECG features are present, treat as follows
1. Myocardial protection
Calcium chloride or gluconate 10 ml of 10% by slow IV injection
No effect on serum potassium concentration but buys time by stabilising the myocardium
2. Drive potassium into ICF
Salbutamol 5 mg nebuliser
Insulin-dextrose infusion: 10 units of actrapid in 50 ml of 50% dextrose IV over 30 minutes
Sodium bicarbonate 50 ml of 8.4% IV
3. Potassium elimination
Calcium resonium PO or per rectum (PR)
Hydrocortisone if thought to be secondary to Addison’s disease
4. Identify and treat the cause
Further management of hyperkalaemia
Consider continuous renal replacement therapy (CRRT) if serum potassium concentration >6.5 mM and refractory to medical management
