The normal concentration of serum potassium is 3.5 – 5.0 mEq/L. When potassium levels climb above the normal limits (>5.0 mEq / L), it is termed Hyperkalemia.

This Daily Doodle captures some of the causes of Hyperkalemia which can be divided into 3 main groups:

1. Excessive intake (aqua coloured area):

–  Potassium Supplements
–  Salt substitutes
–  Blood transfusion
–  Diet (seaweed, avocados, bananas…)

2. Shift from Intracellular to extracellular fluid (pink area):

–  Insulin deficiency (sad pancreas)
–  Tissue destruction
–  Crush injuries
–  Rhabdomyosis
–  Burn
–  Tumor lysis
–  Drugs: B-blockers, digoxin, succinycholine
–  False readings – Blood sample hemolysis, turnicate

3. Decrease Excretion (yellow area)

–  Renal failure
–  Addison’s Disease Hypoaldosteronism
–  Distal tubular dysfunction
–  NSAIDS
–  Potassium sparing diuretics – spironolactone
–  ACE inhibitors (hand of aces on the bottom right)

Symptoms – Hyperkalemia is usually asymptomatic, unless it is severe. As serum potassium levels increase, symptoms start to become evident and ECG changes start to occur. The effect of hyperkalemia on the heart becomes significant over 6 mEq/L. As the levels continue to rise, the symptoms will continue to worsen and can lead to potentially fatal cardiac arrhythmias.

–  Nausea
–  Palpitations
–  Muscle Weakness
–  Muscle stiffness
–  Paresthesia
–  Areflexia
–  Ascending paralysis
–  Hypoventilation

ECG Changes

–  Peaked and narrow T waves
–  Loss of P waves
–  Prolonged PR interval
–  Widening QRS and eventual merging with T-wave (sine-wave pattern)
–  AV block
–  Ventricular fib, asystole

Treatment Mnemonic – C BIG K DROP

C – Calcium gluconate

BIG – B-agonist, Bicarb, Insulin, Glucose

K – Kayexalate

DROP – Diuretics, Dialysis (if life threatening hyperkalemia unresponsive to therapy)

References

1. Merck Manual Professional Edition App. 2009
2. P. Chan and M. Johnson “Treatment Guidelines for Medicine and Primary Care”. 11th Edition. Current Clinical Strategies Publishing. 2010

01/11/13 – Hyperkalemia Medical Daily Doodle by Michiko Maruyama