Lupus nephritis is inflammation of the kidney that is caused by systemic lupus erythematosus (SLE). Also called lupus, SLE is an autoimmune disease. With lupus, the body's immune system targets its own body tissues. Lupus nephritis happens when lupus involves the kidneys.
Up to 60% of lupus patients will develop lupus nephritis. When the kidneys are inflamed, they can't function normally and can leak protein. If not controlled, lupus nephritis can lead to kidney failure.
Symptoms of Lupus Nephritis
Lupus nephritis can be a serious problem, but the symptoms aren't always dramatic. For many, the first noticeable symptom is swelling of the legs, ankles , and feet. Less often, your face or hands may swell.
Other symptoms can vary from person to person and from day to day, such as:
- Weight gain
- High blood pressure
- Dark urine
- Foamy, frothy urine
- The need to urinate during the night
Not all urinary or kidney problems are from lupus nephritis.
You may also be prone to urinary tract infections. These cause burning on urination and require treatment with antibiotics.
Certain lupus medications can also affect your kidneys and cause swelling and other symptoms similar to those of lupus nephritis. Problems related to these medications usually go away after you stop using them.
Lupus Nephritis Diagnosis
The diagnosis of lupus nephritis begins with a medical history, physical exam, and a review of your symptoms. Your doctor will likely order tests to make or confirm your diagnosis. Tests used to diagnose kidney problems include:
- Urine tests
- Blood tests
- Imaging tests such as ultrasound or kidney biopsy
Causes of Lupus Nephritis
When your immune system attacks your kidney, the inflammation can cause lupus nephritis. It's a serious complication of lupus, also called systemic lupus erythematosus, or SLE. Without treatment, long-term inflammation can permanently damage your kidneys.
It's unclear, but some things likely contribute to lupus nephritis, causing your immune system to attack your body. That's why most treatments aim to weaken your immune system.
The things that lead to this faulty immune response aren’t clear, but scientists think they include:
Genes: There are a number of genes that may raise your risk for the lupus, which might also contribute to lupus nephritis. For example, people of certain ethnic descent -- Hispanic, Native American, African, Asian, Pacific Island -- are more likely to get lupus, possibly due to shared genes.
Still, it seems clear that genes aren’t enough by themselves to cause the disease. Even in identical twins (which have identical genes) where one twin has lupus, the other twin is only about 30% more likely than normal to develop the disease.
Hormones (maybe): Women get lupus far more often than men. And lupus symptoms seem to increase before monthly periods and during pregnancy when estrogen is higher.
But medications with estrogen, like birth control pills and hormone replacement therapy, don’t seem to raise the risk of lupus. Scientists are trying to figure out what, if any, connection there is between hormones and lupus and why women seem to get the disease more often.
Environment: It can be hard to figure out exactly which things around you can cause lupus. But there are some factors that scientists have strong suspicions about. These include:
- Cigarette smoke
- Silica, a common mineral from the Earth's crust found in sand, stone, concrete, and mortar
- Mercury
- Viruses including Epstein-Barr, herpes zoster (causes shingles), and cytomegalovirus
- UV light
- Stress
Stages of Lupus Nephritis
There are six stages, or “classes,” of lupus nephritis. The higher the stage, the more serious the disease:
Stage 1
- Minor kidney damage
- No obvious other signs or symptoms
Stage 2
- Some clear damage to the kidney
- Extra blood or protein in your urine that your health care team can detect with lab tests
Stage 3
- More damage that amounts to less than half of important blood vessels in your kidney
- Higher amounts of blood or protein in urine
- Possible high blood pressure
Stage 4
- Damage that amounts to more than half of important blood vessels in the kidney
- Blood or protein in urine
- Possible high blood pressure
- Possible need for dialysis as kidneys stop working properly
Stage 5
- Thickening of important parts of the kidney
- Blood or protein in urine
- Possible high blood pressure
- Dialysis or possible kidney transplant
Stage 6
- Damage to more than 90% of important kidney blood vessels
- When treatment is possible, may need dialysis or kidney transplant
- Plus other signs: Blood or protein in urine and high blood pressure
Lifestyle Changes for Lupus Nephritis
Certain lifestyle habits can help protect your kidneys. With lupus nephritis, you can try to:
- Drink enough fluids to stay well hydrated.
- Eat a low-sodium diet, especially if hypertension is an issue.
- Avoid smoking and drinking alcohol.
- Exercise regularly.
- Maintain a healthy blood pressure.
- Limit cholesterol.
- Avoid medications that can affect the kidneys, such as nonsteroidal anti-inflammatory drugs (NSAIDs).
Your doctor may also suggest eating a diet low in potassium, phosphorus, and protein if there is already loss of kidney function.
Although lupus nephritis is a serious problem, treatment can help you prevent kidney failure.
Treatment for Lupus Nephritis
There are five types of lupus nephritis, and your treatment is based on the type you have. Your doctor will likely do a kidney biopsy to find out your type and then tailor your treatment to meet your particular situation.
Corticosteroids for lupus nephritis
These strong anti-inflammatory meds can lower inflammation. Doctors may prescribe these until your lupus nephritis improves. Because these medicines can cause some potentially serious side effects, they must be monitored carefully. But once your symptoms start to get better, your doctor usually lowers your dosage slowly.
Immunosuppressive medications
These medicines work to dampen your immune system activity and can prevent damage to your kidneys. Your doctor may suggest:
- Belimumab (Benlysta)
- Obinutuzumab (Gazyva)
- Voclosporin (Lupkynis)
Your doctor may also suggest treatments that aren't approved yet, but work for other conditions like cancer. These medicines may include:
- Azathioprine (Imuran)
- Cyclophosphamide (Cytoxan)
- Mycophenolate (Cellcept)
Other lupus nephritis treatments
Your treatment plan may also include medications to prevent blood clots or lower blood pressure, if needed. Even with treatment, loss of kidney function sometimes progresses. If both kidneys fail, you may need dialysis. Dialysis can filter your blood through a machine to remove waste products from your body.
Ultimately, you may need a kidney transplant. Your doctor will review your options with you and prescribe medicines to keep your immune system from rejecting your newly transplanted kidney.
Complications of Lupus Nephritis
The most serious complication of lupus nephritis is permanent damage to your kidneys. Your doctor might call this chronic kidney disease, or CKD. In serious cases, your doctor can see scar tissue in your kidneys.
CKD can worsen over time, until your kidneys stop working. This is called kidney failure, though your doctor might call it end-stage renal disease (ESRD). Currently, around 20% of people with lupus nephritis eventually lose kidney function.
Here are some risk factors for lupus nephritis complications:
- Late diagnosis: It can be harder to control lupus if the condition hasn't been treated for many years.
- Poor health care access: You may not be aware of your lupus without regular visits to your doctor. And you can’t treat the disease until you and your doctor know you have it.
- Not taking your medication: You’re more likely to get serious flare-ups that lead to complications if you can't stick to your treatment plan prescribed by your doctor.
Lupus Nephritis and Race and Ethnicity
For certain ethnic groups, lupus is more likely to lead to complications like lupus nephritis. For example, one study divided people into groups by ethnicity, including groups such as:
- Whites
- Blacks
- Asian-Pacific Islanders (APIs)
- Hispanics
The study found that Black, Hispanic, and API people with lupus had more kidney damage, and were more likely to develop full-blown lupus nephritis. People of color also developed more serious symptoms more quickly, often within the first year of diagnosis.
This is really important because later-stage lupus nephritis can cause a large percentage of lupus-related, serious illness, and life-threatening complications. Scientists aren’t yet sure what accounts for these differences, but continue to study the subject.
Takeaways
Without treatment, lupus nephritis can become a serious, life-threatening complication of systemic lupus erythematosus (SLE). The condition causes inflammation in your kidneys. More common in people of color, early diagnosis can help prevent complications and permanent kidney damage. If you notice leg, ankle, feet, face, or hand swelling, talk to your doctor about lupus nephritis.
FAQs Lupus Nephritis
Do I need to eat differently with lupus nephritis?
Talk to your doctor, but eating the right foods can help your kidneys. Your doctor may suggest eating:
- Less salt and sodium
- Smaller portion sizes that have higher protein like lean chicken, fish, eggs, and bean
- Heart-healthy lean cuts of meat, skinless chicken, fruits and veggies
What is proteinuria?
One main sign of lupus nephritis is higher protein levels in your urine. If your kidneys get damaged, they can leak protein into your urine. This can lead to higher than normal amounts, also called proteinuria.
Will I get kidney failure with lupus nephritis?
Only between 10% to 30% of people with lupus nephritis get kidney failure.
