Potassium Homeostasis

Potassium homeostasis is essential for maintaining the normal resting membrane potential of excitable cells. Yet daily dietary potassium typically far exceeds total extracellular potassium, thus the body has elegant strategies to shift potassium into cells promptly after a meal and then the kidneys efficiently excrete potassium. Potassium excretion depends on adequate kidney perfusion and filtration, sodium delivery to the distal nephron and aldosterone action on the distal nephron. Both hypokalemia and hyperkalemia have been associated with an increase in mortality. In this piece, we share 5 challenging cases to explore normal potassium homeostasis and disorders that can lead to derangements in potassium balance or excretion.