What Is a High Potassium Level?
Key takeaways:
High potassium levels in the blood can affect the way the heart beats. And in severe cases, it can be a life-threatening condition if left untreated.
This condition usually happens in people with kidney disease because the kidneys play a key role in getting rid of excess potassium. It’s much more rare to have high potassium if you have healthy kidneys.
There typically aren’t any symptoms with high potassium levels. So a diagnosis often comes after someone does blood work.
Potassium is an electrolyte that plays an important role in many bodily processes. It helps with things like nerve function, muscle contraction, and the way the heart beats.
We get potassium from the foods we eat. And then the kidneys are in charge of keeping our potassium levels in a normal range. They hold onto the amount we need, and then get rid of any excess potassium in the urine. This ensures that potassium levels stay in the right range for the important bodily functions that need it.
If the potassium level gets too high (a condition called “hyperkalemia”), one of the biggest problems is that the heart can have trouble staying in a normal rhythm. This can even be life-threatening because the can heart can stop beating and lead to cardiac arrest. Read on to find out what can cause high potassium and what treatment looks like when it happens.
What causes high potassium levels (hyperkalemia)?
The kidneys keep a close eye on the body’s potassium levels, so hyperkalemia is rare when the kidneys are functioning normally. But chronic kidney disease (CKD) is a common condition, and decreased kidney function is one of the most important factors that can cause high potassium. If the kidneys aren’t functioning normally, they might not be able to remove extra potassium from the blood. This can lead to a buildup of potassium.
CKD can lead to hyperkalemia on its own. This is particularly true if someone is dependent on dialysis to remove potassium from the blood, and it’s been too long since their last treatment. It can also occur when someone’s CKD progresses and they have a sudden decline in their kidney function.
Hyperkalemia also occurs when someone’s kidney function is stable, but something else happens in the body and the kidney’s cannot handle the new increase in potassium. Things that can suddenly increase the amount of potassium in the blood include:
Rapid cell breakdown: Every cell in the body stores potassium inside it. So anything that causes many cells to die at once can leak large amounts of potassium into the blood. This includes things like traumatic injuries or burns, infection, cancer, chemotherapy treatments, or blood disorders that lead to destruction of red blood cells.
Medications: Different medications can be a common culprit when it comes to high potassium levels. Some medications can prevent the kidneys from removing potassium from the body, such as ACE inhibitors (like lisinopril), aldosterone receptor blockers (like losartan), and potassium-sparing diuretics (like spironolactone).
Conditions that make the blood too acidic: High amounts of acid in the body will pull potassium out of cells and into the blood. Examples of when this happens is in diabetic ketoacidosis or sepsis.
Too much potassium in the diet: Potassium supplements or foods with too much potassium can raise the potassium level as well. This basically only happens to people who have kidney disease.
How do you diagnose high potassium?
Diagnosis requires a blood test to check the potassium levels. A normal range of potassium is between 3.5 and 5 mEq/L. A level of 6 mEq/L or higher can be serious.
Hyperkalemia often doesn’t lead to any specific symptoms. So lab testing usually discovers it. Your provider might specifically order tests to check potassium levels, or a high potassium level could be an incidental finding on blood work intended for some other purpose.
When hyperkalemia does cause symptoms, they might include:
Fatigue
Muscle weakness
Tingling or numbness
Nausea and vomiting
Finally, sometimes changes on an electrocardiogram (ECG) identify hyperkalemia. Potassium plays an important role in the way the heart beats, so hyperkalemia tends to cause very specific abnormalities on an ECG. So if you have an ECG that displays these changes, your provider will check your potassium levels.
How do you treat high potassium levels?
A high level of potassium is a medical emergency that will need medications to get the potassium to safe levels. The main goal of treatment is to help prevent any life-threatening heart rhythms. There are usually three parts to hyperkalemia treatment:
Protecting the heart muscle to prevent arrhythmia
Lowering the potassium level in the blood as quickly as possible
Removing excess potassium from the body
If the potassium level is high enough, or if someone’s ECG is abnormal because of it, they will often get a dose of calcium through an intravenous (IV) line. The calcium helps stabilize the heart rhythm and prevent any arrhythmia, while other medications work to get the potassium levels down.
After calcium treatment, typically the next step includes medications that quickly pull potassium out of the blood. These medications include:
Insulin: While usually people with diabetes use this medication, insulin also pulls the potassium inside the cell, where it can’t harm the heart.
Albuterol: This medication opens the airways for someone with asthma. But similar to insulin, it also helps to pull potassium out of the blood and safely store it inside the cells.
Sodium bicarbonate: This helps bring down the acidity in the blood, and it also helps direct potassium to move inside the cells.
After medications help to pull the potassium out of the blood, the final step in treatment is to remove it from the body. There are several different ways to do this:
Diuretic medications: These common medications, like furosemide (Lasix), can help the kidneys excrete the excess potassium from the body.
Dialysis: If someone’s kidneys are completely shut down (or they’re already dependent on dialysis treatments), dialysis is the most effective way to remove potassium stores in the body.
Potassium binders: These are oral medications that bind potassium in the gastrointestinal tract and prevent the bloodstream from absorbing it. But there’s some controversy as to how effective these are for treating hyperkalemia, so providers don’t always use them.
The bottom line
A high potassium level in the blood is a serious condition because of the way it can affect the heart. Fortunately, the kidneys are really good at keeping potassium at the right level. But people with decreased kidney function often need to monitor their potassium levels, particularly if they start new medications or develop other medical conditions that can affect their kidneys. If potassium levels do get too high, there are medications and treatments that can quickly bring them down to a normal level. It’s best not to delay medical attention in these circumstances.
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References
Hollander-Rodriguez, J. C., et al. (2006). Hyperkalemia. American Family Physician.
Mahoney, B. A., et al. (2005). Emergency interventions for hyperkalaemia. The Cochrane Database of Systematic Reviews.
MedlinePlus. (2022). High potassium level.
National Kidney Foundation. (n.d.). Potassium and your CKD diet.
National Kidney Foundation. (n.d). What is hyperkalemia?
