Hypokalemia and hyperkalemia are electrolyte disorders in which potassium levels in your blood are too low or too high.
Electrolytes are minerals that come from your diet. They’re essential for many functions in your body. They regulate fluid balance, blood pressure, muscle and nerve function, and your heartbeat, among other things.
It’s vital that potassium levels stay within a normal range. Your body usually does a great job of regulating potassium levels for you. But sometimes, due to a health condition or certain medicines, the amount of potassium in your body can get too low or too high.
When potassium drops too low or gets too high, it can severely affect your health. Here’s what you should know about hypokalemia and hyperkalemia, including how to treat and prevent these disorders.
Potassium in Your Body
As with other electrolytes (like sodium, magnesium, and phosphate), potassium affects all of your cells and organs. It’s especially important for kidney and heart function, muscle contraction, and nerve transmission. Your heart relies on the right amount of potassium to beat and pump blood properly.
Potassium comes from the foods and beverages you eat and drink. It’s most abundant in fruits and vegetables, but most whole foods have some amount of potassium. Some of the best sources of potassium include:
- Orange juice.
- White or sweet potatoes.
- Dried apricots.
- Winter squash.
- Kidney beans.
For adults who are 19 and older, males need 3,400 mg of potassium per day, and women need 2,600 mg. Pregnant women need a bit more — 2,900 mg per day.
Your body takes the amount it needs from your diet. Your kidneys remove excess potassium, and it’s excreted through your urine. Normal potassium levels in your blood range between 3.6 to 5.0 mmol/L. Most people with mildly low or high potassium do not have symptoms and are diagnosed by a routine blood test. If your potassium is low or high your doctor may also order an electrocardiogram (EKG) to look for changes in your heart rhythm.
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Causes and Symptoms of Hypokalemia
Hypokalemia means your potassium levels are too low — below 3.5 mmol/L. It’s rare for healthy people to have low potassium, but some health conditions can cause your potassium to drop. Severe vomiting or diarrhea are the most common reasons for hypokalemia because they cause potassium loss.
Digestive disorders like Crohn’s disease or colitis can increase your risk of hypokalemia because they can cause chronic diarrhea. You might also be at risk if you have a bad stomach bug that causes severe vomiting or diarrhea. And you can lose potassium if you’re urinating frequently or sweating heavily.
These medicines can also cause you to lose too much potassium and develop hypokalemia:
- Certain diuretic blood pressure medicines.
- Laxatives or enemas (if you use them in excess).
- Some types of antibiotics.
- Insulin, if you take too high of a dose.
Sometimes, you can develop hypokalemia if you don’t eat enough potassium-rich foods, but that’s rare. But it can happen if you eat a low potassium diet and you lose too much potassium.
If your potassium level is just a little bit low, you might not have symptoms. If it’s very low (less than 2.5mm/L), you can have severe muscle weakness, muscle cramps, and an abnormal heart rhythm.
Hypokalemia can lead to problems with your heart and kidney function. It’s important to call your doctor if you have severe or prolonged vomiting or diarrhea so they can check your potassium levels.
Causes and Symptoms of Hyperkalemia
Hyperkalemia means your potassium levels are too high — above 5.5 mmol/L. It’s less common than hypokalemia and affects less than 5% of people worldwide.
Kidney disease is a leading cause of hyperkalemia. Your kidneys help remove excess potassium from your blood, so you can excrete it in your urine. But if your kidneys aren’t working well, potassium can build up and lead to hyperkalemia.
Some medicines can also raise your risk of hyperkalemia. These include:
- Blood pressure medicines called potassium-sparing diuretics, ACE-inhibitors, or Angiotensin receptor blocker
- The heart medicine digoxin.
- NSAID pain relievers.
As with mild hypokalemia, you may not have any symptoms with mild hyperkalemia. But very high potassium levels (greater than 6.5 mm/L) can cause fatigue, muscle weakness, and an irregular heartbeat.
Treating Hypokalemia or Hyperkalemia
Since potassium is so important in regulating your heartbeat, levels that are too high or too low can have serious consequences. In the worst case, either extreme can cause your heart to stop beating, called cardiac arrest. If your blood tests show hypokalemia or hyperkalemia, your health care provider will take steps to correct your levels.
Your doctor can often treat a mild case of hypokalemia with potassium supplements. For more severe cases, you’ll need IV infusions of potassium. Eating a high-potassium diet alone usually won’t bring very low potassium levels up enough.
If you have hyperkalemia, you’ll have to limit high-potassium foods. Your doctor may also remove some potassium from your body with medicines — or with dialysis if your kidneys aren’t working well. Dialysis is a treatment that does the kidneys’ job of filtering your blood — but with a machine.
Prevention Is Key
It’s unlikely that you’ll develop hypokalemia or hyperkalemia just from eating too little or too much potassium. Both disorders result from other health conditions. So the best way to prevent them is to prevent or manage the underlying health condition. You may need routine blood tests to monitor your potassium levels.
Electrolyte beverages may help prevent hypokalemia if you have a digestive disorder that causes chronic diarrhea or vomiting. Try to drink these if you can’t eat solid foods. When you’re able to eat, include more potassium-rich foods like bananas or potatoes, which are easy to digest.
If you take blood pressure medicines that might cause low potassium, make sure to follow any recommendations about eating a potassium-rich diet. And ask if you should take a potassium supplement.
If you’re at risk for hyperkalemia because of kidney disease, you can work with a dietitian to plan a low potassium diet. And make sure you take the medicines your doctor prescribes as directed to lower your potassium.
National Institutes of Health Office of Dietary Supplements. Potassium. LINK
Simon LV, Hashmi MF, Farrell MW. Hyperkalemia. Updated 2021 Feb 11. In: StatPearls [Internet]. LINK
Castro D, Sharma S. Hypokalemia. Updated 2021 May 7. In: StatPearls [Internet]. LINK
American Family Physician. Potassium Disorders: Hypokalemia and Hyperkalemia. LINK
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