Adult Medical Emergency Handbook - Scottish Intensive Care Society

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DANGEROUS HYPERKALAEMIA
May cause sudden death with no warning features. Symptoms include
paraesthesiae, circumoral tingling, muscle weakness, malaise. There
may be no clinical signs.
Diagnosis: elevated potassium: absolute level and rate of rise are
important. An abrupt rise of 2 mmol e.g. from 4 mmol/l to 6 mmol/l may
cause arrhythmias whilst some patients with chronic renal failure tolerate
higher levels. Consider level >6mmol/l as potentially dangerous.
ECG changes may provide the first clue to hyperkalaemia and
its severity. ECG may be NORMAL in presence of dangerous
hyperkalaemia.
CAUSES OF HYPERKALAEMIA
1. Reduced excretion
• Renal failure
Drugs:
• Potassium sparing diuretics: Spironolactone, Triamterene, Amiloride
• ACE inhibitors, angiotensin II antagonists
• NSAIDs
• Hypoaldosteronism: adrenal insufficiency
2. Shift of K + from cells
• Tissue damage: rhabdomyolysis, trauma, burns, haemolysis, internal
bleeding
• Drugs: suxamethonium, digoxin, ß-blockers
• Acidosis
• Others: hyperosmolality, insulin lack, periodic paralysis
3. Excessive intake
4. Pseudohyperkalaemia
• Thrombocytosis, leukocytosis
• Haemolysis: in vitro or sampling
• Delayed analysis
ECG CHANGES OF HYPERKALAEMIA
• Prolonged PR interval.
• Peaked T waves.
• Widening of QRS interval and flattening/loss of P waves.
• Sine wave proceeding to ventricular fibrillation or asystole.
adult medical emergencies handbook | NHS LOTHIAN: UNIVERSITY HOSPITALS DIVISION | 2009/11
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