Diagnosis and treatment of hyperkalemia.

Hyperkalemia results either from the shift of potassium out of cells or from abnormal renal potassium excretion. Cell shift leads to transient increases in the plasma potassium concentration, whereas decreased renal excretion of potassium leads to sustained hyperkalemia. Impairments in renal potassium excretion can be the result of reduced sodium delivery to the distal nephron, decreased mineralocorticoid level or activity, or abnormalities in the cortical collecting duct. In some instances, all 3 of these perturbations are present. Excessive intake of potassium can cause hyperkalemia but usually in the setting of impaired renal function. We discuss the clinical manifestations of hyperkalemia and outline an approach to its diagnosis and treatment.