Hyperkalemia is a condition caused by higher than normal levels of potassium in the bloodstream.
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. Therefore, most cases of hyperkalemia are caused by disorders that reduce the kidneys' ability to excrete potassium.
Insufficient kidney function may result from disorders such as:
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.
Any time potassium is released from the cells, it may build up in the fluid outside the cells and in the bloodstream. Acidosis leads to the movement of potassium from inside the cells to the fluid outside the cells.
Tissue trauma causes the cells to release potassium. This trauma includes:
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 (potassium sparing diuretics, such as spironolactone, amiloride, or triamterene) and potassium supplements (especially intravenous potassium).
Cardiac arrest (absent heartbeat) may occur at any time during the treatment of hyperkalemia. Hospitalization and close monitoring are required.
Emergency treatment is indicated if the potassium is very high, or if severe symptoms are present, including changes in the ECG .
The goal of acute treatment is to protect the body from the effects of hyperkalemia. Acute treatment may include:
- Cation-exchange resin medications, such as sodium polystyrene sulfonate (Kayexalate) -- to attach to potassium and cause it to be removed from the gastrointestinal tract
- Dialysis -- to reduce total body potassium levels, especially if kidney function is compromised
- Diuretic medications (water pills) -- to decrease total body potassium
- Intravenous calcium -- to temporarily treat muscle and heart effects of hyperkalemia
- Intravenous glucose and insulin -- to reverse severe symptoms long enough to correct the cause of the hyperkalemia
- Sodium bicarbonate -- to reverse hyperkalemia caused by acidosis
Long-term treatment includes treating the cause of the problem and disorders associated with hyperkalemia.
Treatment of chronic renal failure may include:
- Limiting potassium in the diet, including reducing or stopping potassium supplements
- Taking "loop diuretics" to reduce potassium and fluid levels in people with chronic renal failure
People with kidney failure or a history of hyperkalemia should not use a salt substitute as part of a low-salt diet.
The outcome with this condition varies. In some people, the disorder causes deadly complications, while others tolerate it well.
Treat disorders that may cause hyperkalemia promptly. Monitor serum potassium if you have one of these conditions.
Your doctor should assess your kidney function before and while you take potassium supplements. You should not take these supplements unless you have adequate urine output and kidney function.