One of the things I enjoy most is the dismantling of medical dogma. In his brilliant blog Precious Bodily Fluids, nephrologist Joel Topf reviewed some of the hyperkalaemia literature and offers some of the following pearls:
- The ECG is insensitive and non-specific as a means of diagnosing (and in particular ruling out) hyperkalaemia (sensitivity of ‘strict’ criteria of symmetrical peaked T waves that resolve on follow up: 18%; sensitivity of any ECG change: 52%).
- The dangers of calcium treatment for digoxin toxicity-associated hyperkalaemia may be exaggerated and are supported by very weak evidence
- Sodium bicarbonate does not effectively lower potassium but does lower ionised calcium which can increase the risk of hyperkalaemia-associated dysrhythmia