Hyperkalemia is defined as a serum potassium level higher than 5.0 mEq/L. Serum potassium levels higher than 7.0 mEq/L may cause life-threatening arrhythmias and require immediate treatment.
Abdominal cramps occur as a result of hyperactivity of smooth muscle within the peritoneal cavity.
Muscle weakness may occur as a result of increased potassium outside of the cell.
Like abdominal cramping, diarrhea can occur due to the effect of high potassium on smooth muscle, which causes an increase in peristalsis.
Cellular excitability as a result of hyperkalemia causes a decrease in cardiac depolarization, which affects cardiac conduction. This can result in a variety of cardiac arrhythmias, including ventricular fibrillation or asystole.
Due to the faster depolarization of the cardiac action potential from the ventricles, the QT interval is shortened resulting in a narrow and peaked T wave.
IV calcium is indicated in patients with a hyperkalemic emergency as it directly antagonizes the action of potassium on cell membranes, most importantly those of the heart. This is a rapidly acting, short-lasting treatment that should be used for initial stabilization of patients. Calcium can be infused as calcium gluconate or calcium chloride, with gluconate largely preferred due to tolerability.
Patients with hyperkalemia are given infusions of glucose and insulin to drive potassium into cells and thereby decreasing extracellular potassium levels. Insulin is the main driver of potassium in this solution, with glucose added to prevent hypoglycemia.
In mild cases of hyperkalemia and when the kidneys are functioning properly, loop or thiazide diuretics can be given to increase the excretion of potassium from the circulatory system.
Kayexalate is a gastrointestinal cation exchanger, a type of drug that eliminates potassium in the GI tract by exchanging it for other cations. Kayexalate is the prototypal drug of its class and is not often used today as it may increase the chance of colonic necrosis. Newer agents such as patiromer or zirconium cyclosilicate are preferred.
Dialysis is indicated for patients with severe hyperkalemia and kidney impairment. As renal elimination of potassium through loop or thiazide diuretics may be ineffective, hemodialysis is indicated to quickly remove large amounts of potassium from the blood.
Preventing recurrence of hyperkalemia involves educating the patient to reduce dietary potassium, removing an offending medication, or the addition of a diuretic.
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