Potassium homeostasis and hyperkalemic syndromes.

Acute hyperkalemia can be a life-threatening consequence of a variety of pathologic, pharmacologic, and iatrogenic disorders. Recognition and prompt therapy often reverse the electrophysiologic complications within minutes. Therefore, physicians must have a thorough understanding of potassium homeostasis. The causes of hyperkalemia, intracellular-to-extracellular shifts of potassium, excess exogenous potassium loads, and pseudohyperkalemia are discussed.