Hypokalaemia
Hypokalaemia is a disorder of potassium homeostasis characterised by low levels of potassium (<3.5 mmol/L). It's a relatively common electrolyte abnormality.
Grading of severity
Potassium level | Severity |
---|---|
3.5 - 3.0 | Mild |
2.9 - 2.5 | Moderate |
< 2.5 | Severe |
Etiology
Hypokalaemia can occur due to increased potassium loss, redistribution of potassium into cells, or (rarely) insufficient potassium intake. Because the kidneys can reduce potassium excretion to a minimum, and the daily potassium requirement is really low, insufficient intake of potassium rarely causes hypokalaemia by itself, but it may contribute to hypokalaemia due to other causes
Increased potassium loss | Redistribution of potassium into cells |
---|---|
Loop diuretics | Excessive insulin (treatment of diabetic ketoacidosis or hyperglycaemic hypoerosmolar syndrom, refeeding syndrome) |
Vomiting or other gastrointestinal loss | Excessive beta-adrenergic activity (severe stress (like myocardial infarction, traumatic head injury, alcohol withdrawal), administration of beta-adrenergic agonists) |
Hyperaldosteronism, e.g. due to | Alkalosis |
Upper gastrointestinal fluids don't contain much potassium, so loss of the fluid itself does not cause severe hypokalaemia. However, the resulting hypovolaemia can cause hyperaldosteronism, which can cause hypokalaemia.