Lupus nephritis is a kidney disease caused by systemic lupus erythematosus (SLE). It may cause inflammation or, in some cases, kidney damage.

Systemic lupus erythematosus (SLE) is the most common type of lupus, which is a chronic autoimmune condition. This means your immune system attacks the healthy cells, organs, and tissues in your body by mistake.

Approximately 1.5 million people in the United States are living with lupus, with 16,000 new diagnoses every year. Nearly 50% of adults and 80% of children may develop lupus nephritis within 5 years of their SLE diagnosis.

Lupus nephritis occurs when SLE causes your immune system to attack your kidneys.

These organs play a vital role in maintaining body function, which includes:

  • filtering waste products and fluids in your blood
  • maintaining healthy blood levels
  • producing blood cells and essential hormones

Damaged kidneys could make you very ill, and even be life-threatening.

Lupus nephritis may have similar symptoms to those of other kidney diseases.

Symptoms may include:

  • dark, foamy, or bloody urine
  • high blood pressure
  • weight gain
  • urinating often, especially at night
  • swelling in your feet, ankles, and legs

They could also develop at the same time or shortly after your lupus symptoms appear, which could include:

  • stiffness or pain in your joints and muscles
  • fever, fatigue, or headaches
  • sensitivity to light
  • skin rashes
  • mouth or nose sores

Speak with a doctor if you’re experiencing any of these symptoms, especially if you have foamy or bloody urine.

Lupus nephritis symptoms may not appear immediately. However, early diagnosis is crucial to prevent kidney damage and failure, or even death.

A doctor will determine the severity of your kidney damage using a lupus nephritis classification system. This was developed by the World Health Organization (WHO), then later modified by the International Society of Nephrology and the Renal Pathology Society.

The six classes are:

  • Class 1: Minimal mesangial lupus nephritis.
  • Class 2: Mesangial proliferative lupus nephritis.
  • Class 3: Focal lupus nephritis (active and chronic, proliferative and sclerosing).
  • Class 4: Diffuse lupus nephritis (active and chronic, proliferative and sclerosing, segmental and global).
  • Class 5: Membranous lupus nephritis.
  • Class 6: Advanced sclerosis lupus nephritis.

Although there’s no cure for lupus nephritis, the goal of treatment is to help:

  • reduce kidney inflammation
  • stop your immune system from attacking your kidneys
  • provide relief from lupus symptoms

Treatment depends on several factors, such as whether you’re a child, pregnant, or which stage of the disease you’re in. For example, classes 1 and 2 may only require monitoring, while 3 may involve immunosuppressant medication and 6 a kidney transplant.

Common treatments may include:

  • minimizing your protein and salt intake
  • taking a corticosteroid to reduce swelling and inflammation
  • taking blood pressure medication, such as ACE inhibitors or diuretics
  • taking medicines to suppress your immune system, such as cyclophosphamide

If you develop extensive kidney damage or failure, you may require additional treatment.

Regular hemodialysis is the first choice of treatment. This is a procedure in which your blood is cleaned by a filtration machine.

Most people who require dialysis will eventually need a transplant. However, it may take months or years before a donor organ becomes available.

SLE and Lupus nephritis are primarily caused by a type III hypersensitivity reaction. This is an abnormal immune response triggered by certain antigens.

The body then releases inflammatory cells. These, in turn, release certain enzymes and unstable atoms called free radicals, which cause kidney damage and symptoms associated with the condition.

SLE is believed to be triggered by a combination of genetic and environmental factors. There may also be some hormonal triggers, as it tends to be more common in females assigned at birth (FAAB) than in males assigned at birth (MAAB).

In addition, African Americans, Asian and Pacific Islanders, and Hispanics are more at risk for Lupus nephritis than people who are white, according to research from 2020.

Learn more about the causes of SLE.

To diagnose lupus nephritis, a doctor may perform a physical and medical history examination, as well as the following tests:

Blood tests

Blood tests measure how well your kidneys are functioning.

A doctor will look for elevated levels of waste products in your blood, such as creatine and urea. Normally, the kidneys filter out these products.

24-hour urine collection

This test measures the kidney’s ability to selectively filter wastes. It determines how much protein appears in urine after a 24-hour period.

Urine tests

Urine tests may also measure your kidney function by identifying levels of:

  • protein
  • red blood cells
  • white blood cells

High levels of each could indicate damage to your kidneys.

Kidney biopsy

A kidney biopsy is considered the gold standard method of diagnosing lupus nephritis. It’s the most accurate, but also most invasive.

It could also inform your treatment plan, as it helps indicate how far the disease has progressed.

For the biopsy, a doctor will insert a long needle through your abdomen and into your kidney to take a sample of your kidney tissue.

Then, they’ll send the sample to be analyzed in a lab by a pathologist.

Iothalamate clearance testing

This test uses a contrast dye to see how your kidneys are filtering waste products.

Radioactive iothalamate is injected into your blood. A doctor will then test how quickly it’s excreted in your urine.

They may also directly test how quickly it leaves your blood. This is the most accurate test of kidney filtration speed.

Ultrasound

Ultrasounds use sound waves to create a detailed image of your kidney. A doctor will look for anything abnormal in the size and shape of your kidney.

With proper treatment and monitoring, most people with lupus nephritis won’t develop any complications.

That said, 10-30% of people with lupus may have kidney failure. This happens when 85-90% of your kidneys stop working, and may be life-threatening.

Other complications may include:

  • cardiovascular diseases
  • kidney scarring
  • B-cell lymphoma cancer

Early diagnosis and treatment are vital to help maintain kidney health.

What are the first warning signs of lupus nephritis?

One of the first signs of lupus nephritis is bloody or foamy urine.

Other signs and symptoms may include:

  • urinating frequently, especially at night
  • swelling in the feet, ankles, and legs
  • high blood pressure
  • weight gain

What is the life expectancy of someone with lupus nephritis?

The outlook for someone with lupus nephritis depends on the severity of the disease.

That said, recent treatment developments have greatly increased one’s chance of living a normal lifespan.

For example, the 5-year survival rate in the 1950s was 0%. Now, 10-year survival rates are up to 73%.

Can lupus nephritis go away?

Lupus nephritis is a severe complication of lupus, which is a chronic autoimmune disorder.

While there’s no cure, early diagnosis, treatment, and monitoring may help you manage your symptoms and live a normal lifespan.

Treatment may include lifestyle changes, medications, and therapy.

Lupus nephritis is a kidney complication from lupus, which is a chronic autoimmune disease.

Speak with a doctor if you experience symptoms, as early diagnosis is key to maintaining proper kidney function.

Modern treatments have greatly increased a person’s lifespan and quality of life.