Hyperkalemie

Hyperkalemia is an elevated level of potassium in the blood, usually defined as a serum potassium above 5.0 mmol/L. It is a potentially life-threatening electrolyte disturbance because of its effects on cardiac conduction and rhythm. The term hyperkalemie is used in some languages to refer to the same condition.

Causes of hyperkalemia include reduced renal potassium excretion, as in acute kidney injury or chronic kidney disease, and hypoaldosteronism. Shifts of potassium from the intracellular to the extracellular space can occur with acidosis, tissue breakdown such as rhabdomyolysis or tumor lysis syndrome, and insulin deficiency. Increased potassium intake or administration also contributes, particularly with potassium-sparing diuretics (spironolactone, eplerenone, amiloride), ACE inhibitors or ARBs, nonsteroidal anti-inflammatory drugs, and certain antibiotics such as trimethoprim. Pseudohyperkalemia can occur due to hemolysis, leukocytosis, or platelet clumping during sample collection.

Clinical features are often absent or non-specific until levels are high. When present, symptoms may include muscle weakness, paresthesias, or fatigue. Cardiac effects are the main concern; electrocardiographic changes typically progress from peaked T waves to PR prolongation, QRS widening, and potentially a sine-wave pattern or arrest in severe cases.

Diagnosis relies on serum potassium measurement, with simultaneous assessment of kidney function, acid-base status, and medications. An electrocardiogram is often obtained to gauge cardiac risk.

Management depends on grade and symptoms. If there are ECG changes or very high potassium, immediate stabilization with intravenous calcium is recommended. Potassium shifting is achieved with insulin plus glucose, and sometimes beta-agonists or bicarbonate if acidosis is present. Reducing body potassium involves diuretics, potassium binders (sodium polystyrene sulfonate, and newer agents such as patiromer or sodium zirconium cyclosilicate), and, in severe cases or kidney failure, hemodialysis. Discontinuation or adjustment of contributing medications and treatment of the underlying cause are essential.