ABSTRACT
Hypokalaemia may be caused by the following mechanisms: renal potassium loss; extra-renal electrolyte loss; edistribution of potassium from the extracellular to the intracellular compartment; and poor potassium intake. The vast majority of potassium in the body is present within the intracellular compartment, and therefore the serum potassium concentration reflects both total body potassium and the relative distribution of potassium between the intracellular and extracellular compartments. Hypokalaemia is often asymptomatic, but may cause muscle weakness or polyuria. Metabolic alkalosis may occur with severe hypokalaemia in general, and particularly with conditions of mineralocorticoid excess, as well as in Bartter's, Liddle's and Gitelman's syndromes. Loss of sodium chloride from the gastrointestinal tract or skin results in hypovolaemia with secondary hyperaldosteronism, as well as metabolic alkalosis. Both of these factors cause increased renal potassium excretion. Chronic vomiting due to bulimia or anorexia nervosa may lead to dental caries and parotid enlargement. Additional signs of anorexia nervosa include low body mass index and lanugo hair.
