Potassium replacement in Hypokalemia

Abstract

Hypokalemia is defined as plasma potassium (K+) concentration of < 3.5 mEq/l. It is a common electrolyte abnormality with a wide range of presentations. Hypokalemia is reported in < 1% of healthy adults. However, about 20% of hospitalized patients requiring care in medical wards and nearly 50% of patients on either loop/thiazide diuretics exhibit hypokalemia. Hypokalemia is associated with a nearly tenfold increase in-hospital mortality due to its adverse cardiovascular effects.1

Severity of Hypokalemia: 

1. Mild hypokalemia: 3 to 3.4 mEq/l
2. Moderate hypokalemia: 2.5 to 2.9 mEq/l
3. Severe hypokalemia: < 2.5mEq/l

Treatment

Managing hypokalemia aims to prevent/treat life-threatening complications (arrhythmias, paralysis, rhabdomyolysis, and diaphragmatic weakness), replace potassium deficit, and correct underlying cause. The urgency of treatment depends upon the severity of hypokalemia, associated comorbid conditions and rate of decline in serum potassium concentration. The risk of arrhythmia from hypokalemia is more in older patients, patients with organic heart disease, and patients on drugs like digoxin and antiarrhythmics.2

Potassium replacement is the mainstay of therapy in hypokalemia. It is indicated in patients with hypokalemia due to renal or gastrointestinal losses. It should also be considered when hypokalemia is due to redistribution of potassium from the extracellular fluid into the cells (e.g. hypokalemic periodic paralysis, insulin therapy) and if serious complications such as paralysis, rhabdomyolysis, or arrhythmias are present or imminent.

The aetiology of hypokalemia should be identified as quickly as possible. Patients having hypokalemia with concurrent hypomagnesemia due to causes like diarrhea or diuretic therapy can be refractory to potassium replacement alone. Thus, measurement of serum magnesium should be considered in patients with hypokalemia, and, if present, hypomagnesemia should be addressed.