Hyperkalemia (High Blood Potassium)

Symptoms of hyperkalemia include tingling sensations, nausea, tiredness, and muscle weakness.

• Hyperkalemia is an excessive level of potassium in the bloodstream.
  • Potassium has several important functions in the body.
  • It is essential for the normal functioning of the muscles, heart, and nerves.
  • Potassium helps the body regulate the activity of muscles, including the smooth muscle (involuntary muscles, such as the muscles found in the digestive tract), skeletal muscle (voluntary muscles, such as muscles of the extremities and torso), and the muscle of the heart.
  • It is also important for maintaining normal heart electrical rhythm and for normal electrical signals in the nervous system.
• The normal potassium level in the blood is 3.5-5.0 milliEquivalents per liter (mEq/L).
• Potassium levels between 5.1 mEq/L to 6.0 mEq/L are considered to be mild hyperkalemia.
• Potassium levels of 6.1 mEq/L to 7.0 mEq/L are moderate hyperkalemia, and levels above 7 mEq/L reflect severe hyperkalemia.

Excess potassium in the bloodstream can result from diseases of the kidneys or adrenal glands as well as from certain medications. Hyperkalemia can also be the result of potassium moving out of its usual location within cells into the bloodstream.

The majority of potassium within the body is located within cells, with only a small amount located in the bloodstream. A number of conditions can cause potassium to move out of the cells into the blood circulation, thereby increasing the measured level of potassium in the blood, even though the total amount of potassium in the body has not changed. Diabetic ketoacidosis, an emergency that can develop in people with type I diabetes, is an example of a condition in which potassium is drawn out of cells and into the bloodstream.

Similarly, any condition in which there is massive tissue destruction can result in elevated levels of blood potassium as the damaged cells release their potassium. Examples of tissue destruction include

• trauma,
• burns,
• surgical procedures,
• destruction of tumor cells or red blood cells, and
• rhabdomyolysis (a condition involving the destruction of muscle cells that is sometimes associated with muscle injury, alcoholism, or drug abuse).

Moreover, difficulty in drawing blood from veins for testing can traumatize red blood cells, releasing potassium into the serum of the blood sample to cause a falsely elevated reading of hyperkalemia on the blood test.

Any condition that decreases kidney function can result in hyperkalemia, since the kidneys rid the body of excess potassium by excreting it in the urine. Examples of conditions that decrease kidney function are glomerulonephritis, acute or chronic renal failure, transplant rejection, and obstructions within the urinary tract (such as the presence of stones).

The adrenal glands secrete many hormones important for proper body function. Among these is aldosterone, which regulates the retention of sodium and fluid in the kidneys along with the excretion of potassium in the urine. Diseases of the adrenal gland (such as Addison's disease, which causes a decreased aldosterone secretion) lead to a decrease in kidney excretion of potassium resulting in hyperkalemia.

Examples of medications that may lead to elevated potassium levels include

• nonsteroidal anti-inflammatory drugs,
• ACE inhibitors,
• Angiotensin II receptor blockers (ARBs), and
• some types of diuretics.

Hyperkalemia is a relatively common disturbance of electrolytes. Most cases of hyperkalemia are mild and may not produce any symptoms at all. Typically, hyperkalemia that develops slowly over time produces fewer symptoms than a sudden rise in potassium levels.

Usually, symptoms do not become apparent until potassium levels are very high (7.0 mEq/l or greater). Sometimes people with hyperkalemia report nonspecific symptoms such as muscle weakness, tiredness, tingling sensations, or nausea.

A slow heartbeat and weak pulse are more serious symptoms, since these may signal an effect on the electrical activity of the heart. Potassium is responsible for maintaining normal heart rhythm and hyperkalemia can have potentially life-threatening effects. While mild hyperkalemia probably has a limited effect on the heart, moderate hyperkalemia can change in the electrocardiogram (EKG, ECG) recording (EKG is an electrical reading of the activity of the neuromuscular activity of the heart), and severe hyperkalemia can cause the heart to stop beating.

Hyperkalemic periodic paralysis is a rare inherited disorder that can result in sudden hyperkalemia accompanied by muscle paralysis.

Mild hyperkalemia usually does not produce symptoms, while severe hyperkalemia can cause serious symptoms such as weakened pulse, slow heartbeat, or muscle weakness. If you experience any of these symptoms you should seek immediate medical care.

Hyperkalemia is diagnosed by a blood test that measures the potassium level in the blood. Other tests, such as an EKG, may be ordered to look for signs of hyperkalemia if it is suspected. Further testing may be needed to determine the cause of the hyperkalemia.

• The treatment of hyperkalemia is based upon the underlying cause of the hyperkalemia and the severity of symptoms (or the presence of EKG abnormalities) as well as upon the overall health status of the patient.
• Mild hyperkalemia in a healthy individual may be treated on an outpatient basis.
• Emergency treatment is necessary if hyperkalemia is severe and has caused changes in the EKG, suggesting an effect on heart function.
• Severe hyperkalemia is usually treated in the hospital, frequently in an intensive care unit.

Your doctor may recommend a diet low in potassium if you have mild hyperkalemia without symptoms and are otherwise healthy.

Treatment measures can include discontinuing or switching medications if these are responsible for the hyperkalemia. In an urgent situation, intravenous injections of glucose and insulin can help drive potassium back into body cells, and injections of sodium bicarbonate may also be used to promote movement of potassium into cells, reducing its concentration in the bloodstream. Dialysis may be used to remove potassium from the body in severe cases.

Medications may be used to help lower the potassium level and to protect the body from the effects of hyperkalemia, such as heart rhythm disturbances.

• Follow-up with a health care professional is necessary if an individual has been diagnosed with hyperkalemia.
• The type and frequency of follow-up testing will depend on the severity of the patient's condition.

Medications for hyperkalemia can include the following:

• Diuretics increase potassium excretion in the urine.
• Drugs such as epinephrine and albuterol (Ventolin, Proventil, AccuNeb, Vospire, ProAir) that act on beta-2 adrenergic receptors have been used to decrease potassium levels in the blood by increasing its movement back into cells.
• Cation-exchange resins are drugs that bind potassium and lead to its elimination via the gastrointestinal tract.

• It is not possible to prevent the majority of causes of hyperkalemia.
• However, maintaining a healthy lifestyle and following your health care professional's instructions for the management of any chronic medical conditions can help slow or prevent the progression of many diseases that may be associated with hyperkalemia.

The outlook for hyperkalemia is variable and is largely dependent on the severity of the condition as well as the overall health status of the patient and the presence of any related symptoms or chronic medical conditions.