If you’ve ever had abnormal results from your blood work, you may wonder whether your unusual numbers are related to lupus or not. One MyLupusTeam member asked, “Does anyone have problems with low potassium? My potassium is hanging out at around 3.0. If so, how did you correct it?”

Many people with lupus can have kidney problems stemming from lupus nephritis — a complication of systemic lupus erythematosus, the most common form of lupus. Your kidneys help remove waste and maintain the right balance of electrolytes (salts), acids, and other substances in your blood — and that could mean there’s a connection to hypokalemia (low potassium).

Read on to find out whether low potassium is connected to lupus and how you can manage it.

What Is Low Potassium?

Potassium is an electrolyte that keeps your muscles, heart, and nerves functioning well. Potassium levels are measured in what’s called milliequivalents, or millimoles, per liter.

For an adult, normal potassium levels range between 3.5 and 5.2 milliequivalents per liter of blood. Anything lower than 3.5 milliequivalents per liter is considered hypokalemia. A potassium level below 3 milliequivalents per liter is considered severe hypokalemia.

Your kidneys help to maintain your potassium level. In your lupus nephritis, inflammation interferes with renal (kidney) function, preventing your kidneys from working as well as they should.

Symptoms of Low Potassium

You may not notice any symptoms of mild hypokalemia (between 3 and 3.5 milliequivalents per liter). Possible symptoms include:

• Constipation
• Heart palpitations (when your heartbeat feels like it’s fluttering or pounding)
• Tiredness
• Muscle weakness
• Muscle spasms
• Numbness or tingling

If you have severely low potassium (less than 3 milliequivalents per liter), you may experience the following symptoms:

• Muscle twitching or cramping
• Severe muscle weakness
• Hypotension (low blood pressure)
• Light-headedness and fainting
• Heart arrhythmias (abnormal heart rhythm)
• Excessive urination
• Excessive thirst

If you notice symptoms of low potassium, you should contact your doctor right away, especially if you have had vomiting or diarrhea in the previous 24 to 48 hours.

If you experience symptoms of severely low potassium, you may have to go to the hospital. One MyLupusTeam member experienced this, sharing, “This is now the fourth time my potassium levels have bottomed out, sending me to the hospital with heart palpitations.”

Causes of Low Potassium

You may have hypokalemia if you are losing too much potassium from your digestive tract from vomiting, diarrhea, or excessive sweating. Low potassium from a poor diet is rare.

Several medications can cause low potassium, including:

• Diuretics (water pills)
• Certain antibiotics
• Corticosteroids
• Insulin

Some medical conditions can also cause low potassium, such as:

• Some kidney diseases
• Adrenal disorders, such as primary aldosteronism or Cushing’s syndrome
• Alcohol use disorder
• Eating disorders, such as bulimia nervosa

How Can Lupus Nephritis Cause Low Potassium?

Low potassium in people with lupus nephritis might be caused by the disease itself or some medications used to treat it. However, researchers have found that low potassium can also occur in people with lupus nephritis without any known cause.

Inflammation

Lupus nephritis is a complication of SLE, in which your immune system makes immune proteins — called antibodies — that attack your own healthy tissues around your body.

When antibodies attack your kidney tissue, it can cause inflammation. Over time, the inflammation can cause kidney disease. This means your kidneys may not work as well as they should, and you may have trouble controlling your potassium levels.

Medications

Corticosteroids (steroids) — such as prednisone — are immunosuppressive medications that are used to decrease inflammation associated with lupus and lupus nephritis. Steroids can directly cause low potassium by causing your kidneys to put more potassium into your urine. Steroids can also cause adrenal disorders that can cause low potassium.

If you have lupus nephritis, you might also take a diuretic to help with edema (swelling) or high blood pressure. Some diuretics can also cause low potassium, including:

• Hydrochlorothiazide (Microzide)
• Furosemide (Lasix)
• Torsemide (Demadex)
• Bumetanide (Bumex)

Low Potassium Diagnosis

Your doctor will check for low potassium by taking a blood test that measures the amount of potassium in your blood.

A nephrologist — a doctor who specializes in conditions that affect your kidneys — may help make a diagnosis and treatment plan for your low potassium. They may order additional tests to measure how well your kidneys are working (kidney function tests), such as:

• Urine test — This test checks to see if protein is leaking into your urine (called proteinuria). If you have any protein in your urine, your kidneys aren’t working as well as they should.
• Serum creatinine — When your creatinine level is higher than normal, it means your kidneys aren’t working as well as they should.
• Glomerular filtration rate — This test measures how well your kidneys are filtering out the waste, toxins, and extra fluid from your blood. When it is lower than normal, your kidneys aren’t working as well as they should.
• Blood urea nitrogen (BUN) — This test measures the level of the waste product, urea, that is in your blood. When BUN is higher than normal, your kidneys aren’t working as well as they should. It can also be a good indicator of the body’s hydration status.

How Is Low Potassium Treated?

If your potassium is low, treatment involves taking potassium. If you have mildly low potassium, your doctor may prescribe a potassium supplement you take by mouth. If you have severely low potassium, you may need to get potassium infused into your vein in a hospital.

You should only take a potassium supplement under the supervision of your doctor. Getting too much or too little potassium can be dangerous.

A MyLupusTeam member commented, “I have hypokalemia. I take prescription potassium daily and if I even miss one, my potassium drops like a rock.”

Another member shared, “My potassium is low, and I take additional potassium pills two times a day. It helps my legs not feel so heavy and concrete-like.”

Can You Prevent Low Potassium?

If you have lupus nephritis, preventing low potassium might involve preventing lupus flares. Your health care provider may prescribe medications to reduce inflammation and maintain kidney health, such as:

• Prednisone
• Cyclophosphamide (Cytoxan)
• Mycophenolate mofetil (CellCept)
• Hydroxychloroquine (Plaquenil)

You also can talk to your doctor about adding potassium-rich foods to your lupus nephritis diet. Several MyLupusTeam members have suggested oranges, orange juice, and bananas. “Grab some oranges and bananas for potassium,” one member wrote. “Usually, oranges have more potassium and have vitamin C.”

Other potassium-rich foods and beverages include:

• Avocados
• Leafy greens
• Tomatoes
• Bran
• Beans and peas
• Potatoes
• Fish
• Lean beef
• Milk
• Coconut water

If you’ve never had low potassium, you probably don’t need to do anything to prevent it. Talk to your doctor if you’re concerned about your potassium levels.

Talk With Others Who Understand

MyLupusTeam is the social network for people with lupus and their loved ones. On MyLupusTeam, more than 223,000 members come together to ask questions, give advice, and share their stories with others who understand life with lupus.

Have you experienced low potassium? Share your experience in the comments below, or start a conversation by posting on your Activities page.