Hyperkalaemia

Question 1

A serum potassium above (…?) mmol/L = hyperkalaemia

Answer 1

5.5 mmol/L

Question 2

What are the causes of hyperkalaemia

Answer 2

DREAD:

• Drugs (K-sparing diuretics and ACEis)
• Renal failure
• Endocrine (Addison’s)
• Artefact (haemolysis in sample tube causing a falsely elevated potassium)
• DKA

Question 3

What can cause a falsely elevated potassium?

Answer 3

Haemolysis (breakdown of RBCs during sampling)

Question 4

What are the typical ECG signs associated with hyperkalemia?

Answer 4

• Tall tented T waves
• Absent/flattened P waves
• QRS widening

Question 5

What are the cut-off values to determine which patients with hyperkalaemia require urgent treatment?

Answer 5

The following patients require urgent treatment:

• K > or equal to 6 mmol/L with associated ECG changes
• K > or equal to 6.5 mmol/L, regardless of ECG changes

Question 6

Describe the management of hyperkalaemia

Answer 6

Urgent management with:

• Calcium gluconate 10% by slow IV injection
• 10 units Actrapid in 100 mL of 20% dextrose IV (over 30 mins)

Other options include:

• Nebulised salbutamol
• Oral calcium resonium
• Sodium bicarbonate
• Dialysis