Hyperkalaemia

Question 1

Potassium range:

normal?
hyperkalaemia?
moderate hyperkalaemia?
severe hyperkalaemia?

Answer 1

Normal: 3.5-5 mmol/L
Hyperkalaemia: > 5.5 mmol/L
Moderate hyperkalaemia: > 6.0 mmol/L
Severe hyperkalaemia: > 7.0 mmol/L

Question 2

what level of hyperkalaemia is an indication for dialysis?

Answer 2

> 7

Question 3

can beta blockers cause hyperkalaemia?

what do you use for renal failure patients?

Answer 3

beta-blockers interfere with potassium transport into cells and can potentially cause hyperkalaemia in renal failure patients -

remember beta-agonists, e.g. Salbutamol, are sometimes used as emergency treatment

Question 4

why does hyperkalaemia need prompt treatment?

Answer 4

avoid arrhythmias, which may potentially be life-threatening

Question 5

hyperkalaemia effects on ECG?

Answer 5

o Peaking of T waves (occurs first)
o Loss of P waves
o Broad QRS complexes
o Ventricullar fibrillation

Question 6

At which level of hyperkalaemia do you get VF?

Answer 6

> 6 (moderate hyperkalaemia)

Question 7

Tx of Hyperkalaemia?

• if your ECG is fine but you have high K+?
• if you have ECG changes and high K+?
• what can you do IV to increase intracellular uptake?
• what else has the same action as the one above?
• If underlying pathology can’t be corrected then renal replacement therapy may be indicated?

Answer 7

• calcium resonium (binds to K+ in large intestine and secretes it in faeces)
• calcium gluconate - cardioprotective as K+ lowers AP depolarisation threshold whereas Ca2+ increases it to prevent arrhythmias
• IV insulin
• salbutamol nebs
• haemodialysis

Question 8

what drugs increase K+?

Answer 8

ACE-inhibitors
NSAIDs
Spironolactone
Angiotensin Receptor Blockers

ACE and ARBs are inhibitng RAAS - meaning less K+ excreted by aldosterone effect on Na/K pumps