Hyperkalaemia

Question 1

Conditions that cause hyperkalaemia (5)

Answer 1

Acute kidney injury

Chronic kidney disease

Rhabdomyolysis

Adrenal insufficiency

Tumour lysis syndrome

Question 2

Medications that cause hyperkalaemia (5)

Answer 2

Aldosterone antagonists (spironolactone and eplerenone)

ACE inhibitors

Angiotensin II receptor blockers

NSAIDs

Potassium supplements

Question 3

What ECG changes are seen in hyperkalaemia?

Answer 3

ECG is required in all patients with a potassium above 6 mmol/L

Tall peaked T waves
Flattening or absence of P waves
Broad QRS complexes

Question 4

Management of hyperkalaemia

Answer 4

Insulin (e.g. actrapid 10 units) and dextrose (e.g. 50mls of 50%) drives carbohydrates into cells and takes potassium with it, reducing the blood potassium

Calcium gluconate stabilises the cardiac muscle cells and reduces the risk of arrhythmias

Question 5

Other ways to lower serum potassium

Answer 5

Nebulised salbutamol temporarily drives potassium into cells

IV fluids can be used to increase urine output, which encourages potassium loss from the kidneys

Oral calcium resonium draws potassium out of the gut and into the stools. It works slowly and is suitable for milder cases of hyperkalaemia

Sodium bicarbonate (IV or oral) may be considered on the advice of a renal specialist in acidotic patients with renal failure. It drives potassium into cells as the acidosis is corrected

Dialysis may be required in severe or persistent cases associated with renal failure