Hyperkalemia

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Hyperkalemia is an electrolyte disorder where a person has too much potassium in the blood. Electrolytes are minerals (like sodium and potassium) that carry an electrical charge. Hyperkalemia can lead to life-threatening problems with electrical conduction in the heart.

People with chronic kidney disease, diabetes, heart failure, and those taking certain blood pressure medicines are most at risk for hyperkalemia. However, everyone needs to recognize potential symptoms associated with the problem.

Learn more about the symptoms, causes, and treatment of hyperkalemia (too much potassium). Only a healthcare provider can diagnose this electrolyte disorder, so learn when you need to seek care.

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Symptoms of Hyperkalemia

The symptoms of hyperkalemia are often nonspecific if present at all. Therefore, most people will not know they have hyperkalemia unless regular laboratory testing is performed. However, this is usually only done in people at risk for hyperkalemia.

When a person develops symptoms, it is usually because of one of two reasons: the potassium level is very high, or the potassium rose very rapidly. Symptoms can include:

  • Muscle cramps
  • Extremity weakness
  • Fatigue

Genetic Hyperkalemia Disorder

Hyperkalemia periodic paralysis is a rare genetic disorder where certain people develop episodic muscle weakness usually precipitated by cold exposure, rest after exercise, or fasting. The episodes last 15 minutes to one hour.

The most severe manifestation of hyperkalemia is cardiac conduction abnormalities that lead to a heart rhythm problem. This can lead to:

  • Bradycardia (a slow heart rate)
  • Chest pain
  • Palpitations

The likelihood of having such a problem depends on a person‘s risk for hyperkalemia (chronic kidney disease), level of hyperkalemia (higher than 6.5 milliequivalents per liter is very concerning), and how quickly the potassium rises (a rapid rise is problematic).

Causes of Hyperkalemia

The amount of potassium in your blood is mainly balanced by the gastrointestinal tract (intake) and kidneys (excretion). People with a healthy diet and functioning kidneys rarely develop hyperkalemia, even after eating a meal full of potassium.

However, it is difficult to know how common the disease is since many people will not have symptoms until the potassium level is concerningly high. 

Hyperkalemia in a Healthy Person

A person without risks for hyperkalemia can develop life-threatening hyperkalemia after a significant crush injury, such as in a major motor vehicle collision. The crushed cells rapidly release potassium into the blood, and the swift rise can lead to cardiac conduction problems.

People with chronic kidney disease or who take medications that affect kidney function are at the highest risk for hyperkalemia. The specific conditions that put people at risk for the electrolyte disorder include:

  • Chronic kidney disease
  • Diabetes mellitus (chronic conditions in which blood sugar is high)
  • Chronic heart failure (the heart does not pump enough blood for the body's needs)
  • Advanced age
  • Use of certain medications

Diet Recommendations

A diet low in potassium is recommended for individuals at risk for hyperkalemia (people with chronic kidney disease).

What Medications Can Cause Hyperkalemia?

People who take certain medications are at higher risk of developing hyperkalemia. These medications include: 

  • Potassium-sparing diuretics, such as Midamor (amiloride)
  • Angiotensin-converting enzyme inhibitors, such as Zestril (lisinopril)
  • Angiotensin II receptor blockers, such as Avapro (irbesartan)
  • Mineralocorticoid receptor antagonists, such as Inspra (eplerenone)
  • Nonsteroidal anti-inflammatory drugs, such as Motrin (ibuprofen)
  • Lanoxin (digoxin)
  • Heparin
  • Beta-blockers, such as Lopressor (metoprolol)
  • Calcineurin inhibitors, such as Gengraf (cyclosporine)
  • Trimethoprim (found in the antibiotic Bactrim)
  • Pentam (pentamidine) 

Do Not Stop Your Medicines

If you take an antihypertensive (for high blood pressure) medication that might lead to hyperkalemia, do not stop taking it without speaking to your healthcare provider.

Although some medications may increase your risk for hyperkalemia, these medicines show significant overall survival benefits when used appropriately in people with chronic heart failure, hypertension, or diabetes.

Are There Tests to Diagnose the Cause of Hyperkalemia?

Hyperkalemia is diagnosed through a blood test that measures your electrolytes. An abnormally high potassium level is generally considered to be higher than 5.0 milliequivalents per liter (mEq/L). However, some people may not have any symptoms at this or even higher levels (greater than 6.5 milliequivalents per liter).

Pseudohyperkalemia

It is common for a person’s blood level of potassium to be elevated erroneously. This is called pseudohyperkalemia, resulting from fist clenching while your blood is being drawn or a poor blood drawing technique. Therefore, your healthcare provider may request you to have a repeat test before treatment is initiated.

Once a blood test shows that a person has hyperkalemia, a healthcare provider is likely to perform an electrocardiogram (ECG). This test evaluates the heart's electrical system using electrodes placed on your chest.

Hyperkalemia can lead to life-threatening electrical problems in the heart and abnormal rhythms. A healthcare provider needs to determine whether the hyperkalemia is already leading to concerning electrical changes. If so, treatment of hyperkalemia becomes emergent rather than urgent. 

How to Treat Hyperkalemia

Treatment will depend on whether there is acute or chronic hyperkalemia.

Acute Hyperkalemia

The treatment of hyperkalemia can depend on how high the potassium is and whether the change has happened quickly or gradually. It can also depend on whether the potassium level is beginning to affect your heart. Therefore, a healthcare provider may perform an ECG to look for electrical problems. 

The decision to treat a high potassium level rests with a healthcare provider, especially since the diagnosis cannot be made unless blood tests are performed. Generally, a serum potassium level greater than 5.5 milliequivalents per liter is a threshold for treatment.

People With Chronic Kidney Disease Can Tolerate a Higher Potassium

People with chronic kidney disease, especially those on dialysis, seem to tolerate a higher potassium level than those without chronic kidney disease.

Experts think that these people develop “resistance” to higher potassium levels since they are likely to have moderately high levels regularly. Therefore, they are less likely to develop symptoms or cardiac problems when the potassium level is mild-to-moderately elevated.

When a healthcare provider is concerned about a rapid rise in potassium or if an individual has ECG changes, emergency treatment will be initiated and will first stabilize the heart. The most critical medication at this point in treatment is calcium gluconate or calcium chloride. This medication specifically stabilizes the electricity in the heart.

Additional treatments that will commence include:

These medications will help lower the blood potassium level by moving the potassium inside the cells. It is important to know that a blood potassium level measures potassium outside your cells. Potassium inside a cell is less dangerous and is not measured on the blood test. To rid the blood and body of too much potassium, a person must receive:

  • Hemodialysis: Blood is removed through a line in a vein. Then, it's filtered through a dialyzer instrument and returned to the person via another line.
  • Certain diuretics, such as Lasix (furosemide), eliminate the potassium in the urine.

Chronic Hyperkalemia

People with chronic hyperkalemia are challenging to spot because they are usually asymptomatic. Often, chronic hyperkalemia is only detected through regular laboratory testing.

The treatment for chronic hyperkalemia also includes hemodialysis or certain diuretics, but typically healthcare providers modify the dose or type of antihypertensive medication that is potentially leading to chronic hyperkalemia.

However, another alternative is to use medications that bind to potassium and eliminate it through the gastrointestinal tract. These potassium binders allow your healthcare provider to keep you on beneficial antihypertensive medications while treating chronic hyperkalemia. These medications include:

Risks and Benefits of Newer Medicines

Veltassa and Lokelma are new agents that can be pretty expensive. However, research studies have shown that when these medications are used to treat hyperkalemia in people with chronic heart failure, the benefits outweigh the financial costs.

Complications and Risk Factors Associated With Hyperkalemia

There are no major chronic long-term complications associated with hyperkalemia. However, people with repeated episodes of hyperkalemia are at higher risk of dying from the electrolyte problem that can lead to cardiac arrest.

Generally, the people at the highest risk for death from hyperkalemia are those with multiple medical issues or those who are critically ill in the hospital. 

When to See a Healthcare Provider

Hyperkalemia often does not lead to symptoms, so knowing when to seek care can be challenging.

However, if you develop severe generalized weakness or have difficulty moving your lower extremities, there is a chance you have an electrolyte problem. In this situation, you should seek care for further testing to evaluate for hyperkalemia along with a whole host of other medical problems.

People with risk factors for hyperkalemia should follow their healthcare provider's instructions regarding medications and diet to avoid dangerous potassium levels.

Summary

Hyperkalemia is an electrolyte disorder where the body has too much potassium. Symptoms are often lacking, but some people can develop muscle cramps and extreme weakness.

The most common cause of hyperkalemia is chronic kidney disease, but people who take certain antihypertensive medications are also at risk for the problem. Hyperkalemia can only be diagnosed through a blood test.

Treating acute hyperkalemia is life-saving and includes medications that stabilize the heart and remove potassium from the body. Knowing if you have hyperkalemia can be challenging, so it’s vital to seek care when you feel extreme weakness. Furthermore, people at risk for hyperkalemia should have regular blood checks.

A Word From Verywell

Hyperkalemia in healthy people is rare. However, if you feel extreme weakness or muscle cramps, you could have any electrolyte disorder, including hyperkalemia. Therefore, you should seek care.

If you are at risk for hyperkalemia based on your underlying medical problems or medications, discuss regular testing with your healthcare provider to ensure a proper potassium level.

Frequently Asked Questions

  • Are there home tests for hyperkalemia?

    There are no home tests that can be performed to evaluate for hyperkalemia.

  • What are examples of foods that are high in potassium and should potentially be avoided by people at risk for hyperkalemia?

    Foods high in potassium include winter squash, bananas, lentils, spinach, broccoli, avocado, oranges, cantaloupe, and dried fruits, such as raisins, dates, and prunes.

  • Are there other illnesses with rapid cell turnover that can lead to hyperkalemia?

    Yes. Hyperkalemia can develop if cells in your body are rapidly damaged (like in a crush injury). Other instances when this might occur include:

    • Extreme physical exercise or weight lifting
    • Tumor lysis syndrome related to cancer
    • Extreme heat illness
    • Use of sympathomimetic drugs (stimulants that increase heart rate and blood pressure) like cocaine
5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Genetic and Rare Diseases Information Center. Hyperkalemic periodic paralysis.

  3. Viera AJ, Wouk N. Potassium disorders: hypokalemia and hyperkalemia. Am Fam Physician. 2015;92(6):487-495.

  4. Montford JR, Linas S. How dangerous is hyperkalemia? J Am Soc Nephrol. 2017;28(11):3155-3165. doi:10.1681/ASN.2016121344

  5. Bounthavong M, Butler J, Dolan CM, et al. Cost-effectiveness analysis of patiromer and spironolactone therapy in heart failure patients with hyperkalemia. Pharmacoeconomics. 2018;36(12):1463-1473. Erratum in: Pharmacoeconomics. 2019. doi:10.1007/s40273-018-0709-3

By Christine Zink, MD
Dr. Christine Zink, MD, is a board-certified emergency medicine with expertise in the wilderness and global medicine. She completed her medical training at Weill Cornell Medical College and residency in emergency medicine at New York-Presbyterian Hospital. She utilizes 15-years of clinical experience in her medical writing.