Treatment of hypokalemia

Abstract

Normal serum levels of potassium range from 3.5 to 5mM/L, and whole body content of potassium amounts to 50 mM/kg (98% is located within the cells). Serum levels of potassium below 3.5 mM/L are classified as hypokalemia, which becomes severe if serum levels drop below 2.5 mM/L. Signs and symptoms of hypokalemia could be: muscle weakness, paresis or paralysis, paresthesias, obstipation, nausea, sometimes vomiting, muscle cramps, polyuria, polydipsia, depression and/or psychotic states. Besides measuring serum levels of potassium, those of magnesium, calcium, phosphate, bicarbonate (as well as blood pH) and glucose should also be measured, since their disturbance is often linked to hypokalemia. A patient with hypokalemia should be connected to ECG monitoring, an intravenous access should be obtained and respiratory status checked. Mild hypokalemia is treated by correction of causes, and moderate by oral potassium supplementation. Severe hypokalemia is treated by intravenous potassium supplementation. If hypomagnesaemia is also present, it should be corrected first, since its correction is prerequisite for normalization of potassium levels. Intravenous supplementation is performed by potassium chloride (7.4% solution) diluted with 500 ml of simple physiological solution. Daily dose should not overcome 90 mM, and administration rate should not be faster than 20 mM per hour. The diluted solution of potassium chloride should be thoroughly mixed before its connection to intravenous set, in order to prevent layering of potassium within the solution.