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What causes high potassium? Diagnosis, prevention, and treatment

Medically reviewed by Anne Jacobson, MD, MPH
Board-Certified Family Physician
Updated May 3, 2024  •  Published Apr 12, 2023
Fact Checked
In this article:

Overview: What is high potassium?

High potassium (hyperkalemia) is a common and potentially life-threatening elevation of potassium levels in the blood. Serum potassium levels affect the electrical properties of the heart and muscles, so very high potassium levels can lead to fatal heart rhythm problems (arrhythmias). The most common cause of hyperkalemia is kidney dysfunction. Hormone problems, changes in the acid balance in the blood, or taking certain drugs are also reasons people have high blood potassium. Treatment can be fairly low-key if potassium levels aren’t too high and there aren’t any heart rhythm problems. When potassium levels shoot up suddenly or start causing abnormal heartbeats, medical treatment is much more urgent and intense.

Key takeaways:

  • High potassium is a common health condition that can affect anyone regardless of age, sex, race, or ethnicity. 

  • High potassium is caused by kidney dysfunction, hormone disorders, acidosis, insulin deficiency, cell destruction, dehydration, cancer treatment, some medications, and excessive potassium intake.

  • Risk factors for high potassium include male sex, low body weight, kidney disease, diabetes, adrenal gland problems, stroke, coronary heart disease, congestive heart failure, smoking, and use of certain medications.

  • Symptoms of high potassium may include heart palpitations, muscle weakness, and bizarre skin sensations like tingling. Often, however, hyperkalemia has no symptoms.

  • High potassium requires a medical diagnosis.

  • High potassium generally does require treatment. It typically resolves with treatment within hours if treatment is urgent or days if treatment is more low-key.

  • Treatment of high potassium may include dietary or medication changes in less serious cases. Urgent medical care, monitoring, intravenous calcium, prescription medications, or dialysis may be required in severe cases. 

  • High potassium is sometimes preventable by adopting a low-potassium diet, taking different medications, and, for kidney patients, keeping dialysis appointments faithfully. 

  • Use coupons from SingleCare for high potassium treatments such as Lasix (furosemide), Lokelma (zirconium cyclosilicate), and Veltassa (patiromer), to save up to 80%.

What causes high potassium?

High potassium is defined as a high level of potassium in the blood. Most potassium in the body is in the cells, not the blood. Potassium inside the cells is not usually a problem. But high blood potassium happens for three major reasons:

  • There’s too much potassium in the body (excess potassium)

  • Too much potassium is being released into the bloodstream by the body’s cells 

  • Cells are being destroyed and releasing their contents—including potassium—into the bloodstream 

The most common cause of high blood potassium is acute or chronic kidney disease or kidney failure. When the kidneys don’t work right, they don’t eliminate enough potassium in the urine. This causes potassium to build up in the body. 

Excess potassium is caused by:

In some cases, too much potassium leaves the cells and enters the bloodstream, increasing the amount of potassium in the blood. Causes include:

Finally, if cells in the body die, they release their contents into the bloodstream. This includes potassium, so cell death can cause sudden spikes in blood potassium. The most common causes include:

  • Muscle damage

  • Blood cell death

  • Blood disorders that cause blood cell death including hemolytic anemia

  • Cancer treatment

Blood draws are another common cause of a high potassium result. But this isn’t true hyperkalemia. It happens because of the way the blood was drawn or processed. When high blood potassium is discovered in a blood test, especially in someone who doesn’t have risk factors for high potassium, another test is often done to double check the results. 

Risk factors for high potassium

Risk factors for hyperkalemia include:

  • Male sex

  • Kidney disease

  • Kidney insufficiency

  • Low body weight

  • Diabetes

  • Adrenal gland problems

  • Coronary heart disease

  • Heart failure

  • Stroke

  • Smoking

  • Use of certain medications, especially potassium-sparing diuretics and blood pressure medications

Is high potassium serious? When to see a doctor

Healthcare professionals take high blood potassium seriously, even if it’s a mild case. If blood potassium gets too high, it can affect heart functioning and lead to serious complications like a heart attack or death.

Most people won’t know that they have a problem with potassium levels. Mild cases usually have no symptoms. People with chronic hyperkalemia often have no symptoms even when potassium levels are dangerously high. The only way to know is through a blood test.

See a healthcare professional if you do have symptoms like muscle weakness or heart palpitations. If these symptoms are severe, go to an emergency room.

RELATED: Hyperkalemia symptoms: what are the early signs of hyperkalemia?

How is high potassium diagnosed?

High potassium is diagnosed with a blood test. However, the healthcare provider will also take a medical history and perform a physical examination to make sure the heart is all right and to identify a possible cause. 

The medical history will help track down the cause of the problem. Be prepared to answer questions like:

  • Do you have kidney disease?

  • Are you on dialysis?

  • Have you missed a dialysis appointment?

  • What medical conditions do you have?

  • Are you being treated for cancer?

  • What drugs are you taking?

  • What dietary supplements are you taking?

  • What kinds of food do you eat?

  • Have you noticed any other symptoms like muscle weakness, nausea, vomiting, or diarrhea?

If there’s any risk that the heart is involved, the doctor will order an electrocardiogram (ECG) to determine if the heart’s rhythm is normal. If it’s not, you may be taken to a hospital depending on how serious the heart arrhythmia is.

Other blood or urine tests may be needed to assess kidney function and look for other causes such as high blood sugar, blood disorders, or acidosis.

Is high potassium hereditary?

A rare type of genetic disorder called pseudohypoaldosteronism can cause acidosis and high potassium. It’s a problem with the kidneys and mimics an adrenal gland problem. The result is low sodium levels, high potassium levels, and acidic blood. These problems usually appear within a few days of birth, so high potassium later in life is almost surely due to nonhereditary causes.

Is high potassium treatable?

High serum potassium is treatable. The goal of treatment is to first make sure the heart is okay. After that, the goal is to return the blood to normal potassium levels by getting rid of potassium. Any underlying condition will then need to be treated.

For mild cases, doctors may treat the problem with low-key treatments that will gradually bring down potassium levels. These include:

  • Keeping to a dialysis schedule for people with severe kidney disease

  • Low-potassium diet

  • Stopping or lowering the dose of medications that cause high potassium

In general, medications that help lower potassium aren’t used for mild cases, but they might be. They’re usually reserved for moderate to severe cases. The most commonly used medications to lower potassium include potassium binders, which remove potassium from the digestive tract, and loop diuretics (“water pills”), which increase the excretion of potassium through the kidneys.

For more severe cases, treatments might include:

  • Emergency intravenous calcium to restore normal heart rhythms

  • Insulin and glucose to push potassium back into cells

  • Inhaled bronchodilators such as albuterol to increase the effects of insulin and glucose

  • Sodium bicarbonate to treat acidosis

  • Dialysis in the most severe cases to quickly remove potassium from the blood

These treatments are only given in a hospital setting with close monitoring by healthcare professionals.

How to prevent high potassium

For conditions like kidney insufficiency, cancer treatment, blood disorders, or acidosis, it’s best to follow your healthcare provider’s instructions to help prevent high potassium.

There are a few other tips that can help:

  • For people with kidney disease, do not miss dialysis sessions

  • Get regular blood tests if high potassium is an ongoing problem

  •  Limit high-potassium foods like apricots, raisins, oranges, bananas, cantaloupe, avocados, lentils, squash, potatoes, carrots, spinach, tomatoes, peanut butter, bran, salmon, and dairy products

  • Avoid salt substitutes

  • Avoid potassium supplements or multivitamins containing potassium

  • Talk to your healthcare provider before taking herbal supplements. A few that may raise potassium levels include milk thistle, dandelion, certain types of ginseng, and turmeric.

  • Avoid drugs like aspirin or ibuprofen unless instructed by your healthcare provider

RELATED: How to lower potassium levels

Most importantly, get tested regularly

Anyone who has had high potassium or is at risk for the condition should visit a healthcare professional regularly. That’s because people with high potassium typically don’t know it. There are usually no symptoms until potassium levels are very high. High potassium levels are not usually discovered until a healthcare provider orders a blood test. People with a history of high potassium, kidney disease, diabetes, adrenal disease, or taking certain medications should have their blood checked regularly. Your healthcare provider will let you know how often to have this done.

FAQs about high potassium causes

What causes high potassium in older adults?

The most common cause of high potassium in any group of people is kidney dysfunction. That includes older adults, who are more likely to have kidney problems than younger adults. Seniors are also more likely to have conditions that are associated with high potassium, including diabetes.

What drugs cause high potassium?

The most common drugs that cause high potassium are hypertension drugs like ACE inhibitors and angiotensin II receptor blockers. Potassium-sparing diuretics are another common culprit. People taking these drugs will usually be given regular blood tests to measure electrolyte levels.

What kind of cancer causes high potassium?

Cancer does not usually cause high potassium levels, but cancer treatment can. Chemotherapy and radiation treatments kill cancer cells, sometimes very rapidly. When the tumor cells die, they release their contents into the bloodstream. That includes potassium, so serum potassium may spike after cancer treatments. Sometimes, so many cancer cells die off that patients get very sick, a condition called tumor lysis syndrome. One of its most threatening aspects is dangerously high potassium.

Can vitamin D cause high potassium?

Vitamin D does not cause high potassium levels, but it can raise levels of calcium too much if taken in excess. It does not affect potassium levels significantly.

What’s next? Additional resources for people with high potassium

Test and diagnostics

Treatments

Scientific studies and clinical trials

Medically reviewed by Anne Jacobson, MD, MPH
Board-Certified Family Physician

Anne Jacobson, MD, MPH, is a board-certified family physician, writer, editor, teacher, and consultant. She is a graduate of University of Wisconsin School of Medicine and Public Health, and trained at West Suburban Family Medicine in Oak Park, Illinois. She later completed a fellowship in community medicine at PCC Community Wellness and a master's in Public Health at the University of Illinois-Chicago. She lives with her family near Chicago.

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