K⁺ and Mg²⁺ Dyshomeostasis in Acute Hyperadrenergic Stressor States

Acute stressor states are linked to neurohormonal activation that includes the adrenergic nervous system. Elevations in circulating epinephrine and norepinephrine unmask an interdependency that exists between K⁺ and Mg²⁺ based on their regulation of a large number of Mg²⁺-dependent Na⁺-K⁺-ATPase pumps present in skeletal muscle. The hyperadrenergic state accounts for a sudden translocation of cations into muscle with the rapid appearance of hypokalemia and hypomagnesemia. The resultant hypokalemia and hypomagnesemia will cause a delay in myocardial repolarization and electrocardiographic QTc prolongation raising the propensity for supraventricular and ventricular arrhythmias. In this review, we focus on the interdependency between K⁺ and Mg²⁺, which is clinically relevant to acute hyperadrenergic stressor states found in patients admitted to intensive care units.