Definition
Hypokalaemia occurs more commonly and in a broad range of patients. However, hyperkalaemia is more serious and largely occurs in patients with some underlying renal or acid base abnormality [2].
Hypokalaemia
| Mild | 3.0-3.5 mmol/L |
| Moderate | 2.5-3.0 mmol/L |
| Severe | <2.5 mmol/L |
Hypokalaemia is defined as K(S) < 3.5 mmol/L. Symptoms are more likely with lower values.
Hyperkalaemia
| Mild | 5.5-5.9mmol/L |
| Moderate | 6.0-6.5 mmol/L |
| Severe | > 6.5 mmol/L |
Hyperkalaemia is the most common electrolyte disorder associated with life threatening arrhythmias and cardiac arrest. It is defined as 5.5mmol/L [3].
Mild hyperkalaemia is common and often well tolerated in patients with chronic renal failure. K(S) > 10 mmol/L is usually fatal.
Learning bite
K(s) must always be checked in disturbances of cardiac rhythm.