Disorders of potassium homeostasis Hypokalemia and hyperkalemia

Hypo- and hyperkalemia are the most commonly encountered electrolyte abnormalities in hospitalized patients [1,15,16,29]. Although no data are available concerning their specific prevalence in critically ill patients, one might expect these abnormalities to occur frequently because of the disruption in normal homeostasis inherent in critical illness and the multiple interventions necessary for care. Hypo- and hyperkalemia are more likely to contribute to morbidity and mortality in this group of patients. Although recognition is simple, requiring only measurement of serum [K+], appropriate management requires an understanding of normal K+ homeostasis and the ways it can be disrupted. In this article, normal K+ homeostasis and the pathophysiology and management of hypo- and hyperkalemia are discussed with special attention to critically ill patients.