Hyperkalaemia

Last Updated on August 19, 2026

Definition

• Mild hyperkalaemia: >5.5 – 6.0 mmol/L
• Moderate hyperkalaemia: >6.0 – 7.0 mmol/L
• Severe hyperkalaemia: >7 mmol/L

💡Tips
– Check formal RP result, to look for documentation of ‘haemolysed blood‘ in the formal report. If so, the ‘hyperkalaemia’ might not be reliable and RP should be repeated prior to giving treatment.
– Do ECG! If ECG shows features of hyperkalaemia, treatment should be given immediately instead of waiting for RP

Causes

Common causes:
• Pseudo-hyperkalaemia i.e. Haemolysed blood
• Metabolic acidosis e.g. DKA
• Medications e.g. potassium supplement (oral / IV), potassium sparing agent (e.g. spironolactone), ACE inhibitor
• Tumour lysis syndrome
• Severe intravascular haemolysis e.g. severe malaria
• Tissue necrosis / crush injury
• Hypoaldosteronism e.g. Addison’s disease
• End stage renal failure

Classification:
• Decreased renal excretion: Renal failure, Mineralocorticoid deficiency, Drugs, Acidosis
• Increased potassium intake
• Increase release from cells: shift out from cells (e.g. insulin insufficiency, acidosis), tissue breakdown (e.g. tissue necrosis / crush injury)

ECG Changes

• Loss of P waves
• Tall tented T waves
• Widened QRS complex
• May indicate potassium more than 8 mmol/L!!! (absent P wave + broad QRS complex + absent ST segment)

• Prolonged PR segment
• ST elevation

Treatment

Oral medication – for mild hyperkalaemia

e.g. Oral Kalimate 5 – 10 g TDS // Oral Resonium A 5 – 30 g 4 – 6 hourly

Lytic cocktail – for acute treatment of hyperkalaemia

1. IV Calcium gluconate 10% 10 mL over 10 minutes, then
2. IV Dextrose 50% 50 mL, then
3. IV Actrapid 10 units (0.1 mL)

💡Tips:
– HO should know how to prepare and administer lytic cocktail

Others

• Haemodialysis especially for ESRF patient whose HD is due / AKI
• Stop any potassium supplement (e.g. Mist KCl / Tab slow K / Potassium in IV drip)

Exam Tips

• ECG features of hyperkalaemia
• What are the components of lytic cocktail ?