Hyperkalemia is a blood potassium level above about 5.0 mmol/L, most often from kidney failure, certain drugs or potassium shifting out of cells. High potassium disturbs the electrical system of the heart and can cause deadly arrhythmias.
Key symptoms
- Often no symptoms
- Muscle weakness or heavy legs
- Palpitations
- Nausea
- Tingling or paralysis in severe cases
What you find on exam
- Slow or irregular pulse
- Muscle weakness with reduced reflexes
- Volume status and urine output
- Clues to the cause: kidney disease, crush injury, burns
Tests
- Repeat potassium if the sample may be hemolyzed; check creatinine and glucose
- 12-lead ECG: peaked T waves, wide QRS, loss of P waves, sine wave
- Blood gas for acidosis
- Drug review: ACE inhibitors, ARBs, spironolactone, NSAIDs, trimethoprim
Treatment basics
- ECG changes: IV calcium gluconate to protect the heart
- Shift potassium into cells: IV insulin with dextrose and nebulized albuterol
- Remove potassium: loop diuretics, a binder such as sodium zirconium cyclosilicate, or dialysis
- Stop potassium supplements and causative drugs
- Continuous cardiac monitoring and repeat levels
Red flags
- Any ECG change, especially a wide QRS or bradycardia
- Potassium above 6.5 mmol/L
- Muscle paralysis or cardiac arrest
Practice it in Making Synapses
Making Synapses cases
Related guides
Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.