Disorders of hypo- and hyperkalemia

Hypokalemia or hyperkalemia may be present as an important feature of a large number of clinical entities. To understand the means by which a hypokalemia or hyperkalemic state may be generated, it is necessary to appreciate those factors which influence the external balance of potassium and the entities which effect its transcellular distribution. In this review the role of the kidney and the gastrointestinal tract in the regulation of the external balance of potassium is briefly discussed. This is followed by a description of the clinical disorders associated with hypokalemia and hyperkalemia.