Hyperkalaemia

Question 1

what is the management of K+ >6.5 mmol/L or ECG changes?

Answer 1

1. 10ml of 10% calcium gluconate over 10 mins (cardioprotective)
2. IV insulin in 25g glucose (causes intracellular K+ shift)
3. nebulised salbutamol (causes intracellular K+ shift)

Question 2

what ECG changes are seen in hyperkalaemia?

Answer 2

1. tall tented t-waves
2. flattened p-waves
3. prolonged PR interval
4. widened QRS complexes
5. idioventricular rhythms
6. sine wave patterns
7. VF/asystole

in order of severity

Question 3

what are the categories of causes of hyperkalaemia?

Answer 3

• impaired excretion
• increased release from cells
• ‘pseudohyperkalaemia’/artefact

Question 4

describe causes of impaired excretion leading to hyperkalaemia

Answer 4

• acute kidney injury
• chronic kidney disease
• ACEi
• potassium sparing diuretics (e.g. spironolactone)
• NSAIDs
• heparin/LMWH
• ciclosporin
• high dose trimethoprim
• hypoaldosteronism (e.g. renal tubular acidosis type 4)
• addisons disease

Question 5

how does heparin/LMWH cause hyperkalaemia?

Answer 5

inhibits aldosterone release

Question 6

describe the causes of increased K+ release from cells leading to hyperkalaemia

Answer 6

• lactic acidosis
• insulin deficiency
• rhabdomyolysis
• tumour lysis syndrome
• massive haemolysis
• digoxin toxicity
• beta blockers

Question 7

describe the causes of ‘pseudohyperkalaemia’/artefact leading to hyperkalaemia

Answer 7

• haemolysis
• delayed analysis
• contamination with potassium EDTA anticoagulant in FBC bottles
• thrombocytopenia

Question 8

what is the management of hyperkalaemia without ECG changes?

Answer 8

IV insulin + dextrose given over 15mins

Question 9

what is the management of hyperkalaemia in stable patients with a K+ <6.0 mmol/L?

Answer 9

oral calcium resonate 15mg QDS PO