Hyperkalemia

Hyperkalemia is higher-than-normal levels of potassium in the blood.

Causes, incidence, and risk factors

Potassium is involved in regulating muscle tissue, and is part of digestion, metabolism, and homeostasis (maintaining a balance between the many electrical and chemical processes of the body).

Hyperkalemia occurs when the level of potassium in the bloodstream is higher than normal. This may be related to an increase in total body potassium or the excess release of potassium from the cells into the bloodstream.

The kidneys normally remove excess potassium from the body. 

High levels of potassium (hyperkalemia) may be due to:

• Addison's disease (rare)
• Blood transfusion
• Certain medications
• Crushed tissue injury
• Hyperkalemic periodic paralysis
• Hypoaldosteronism (very rare)
• Kidney failure
• Metabolic or respiratory acidosis
• Red blood cell destruction
• Too much potassium in your diet

The hormone aldosterone regulates kidney removal of sodium and potassium. Lack of aldosterone can result in hyperkalemia with an increase in total body potassium. Addison's disease is one disorder that causes reduced aldosterone production.

If the kidney is working properly, and there is enough aldosterone, tissue trauma alone rarely leads to hyperkalemia. A normally functioning kidney will remove the excess potassium that has been released from the cells.

Increased intake of potassium can cause hyperkalemia if kidney function is poor. Salt substitutes often contain potassium, as do many "low-salt" packaged foods.

Hyperkalemia may be caused by medications, including medications that affect kidney function (potassiumsparing diuretics, such as spironolactone, amiloride, or triamterene) and potassium supplements (especially intravenous potassium).

Symptoms

Hyperkalemia often has no symptoms. Occasionally, people may have the following symptoms:

• Irregular heartbeat
• Nausea
• Slow, weak, or absent pulse

Signs and tests

• ECG may show changes related to hyperkalemia
• ECG may show potentially dangerous arrhythmias:
  • Heart block that may become a complete heart block
  • Slower than normal heartbeat (bradycardia) that progressively slows
  • Ventricular fibrillation
• Pulse may be slow or irregular
• Serum potassium is high