Lupus nephritis

Definition

Lupus nephritis is a kidney disorder that is a complication of systemic lupus erythematosus.

Alternative Names

Nephritis - lupus; Lupus glomerular disease

Causes, incidence, and risk factors

Systemic lupus erythematosus (SLE, or lupus) is an autoimmune disease. This means there is a problem with the body's immune system.

Normally, the immune system helps protect the body from harmful substances. But in patients with an autoimmune disease, the immune system cannot tell the difference between harmful substances and healthy ones. As a result, the immune system attacks otherwise healthy cells and tissue.

SLE may damage different parts of the kidney, leading to interstitial nephritis, nephrotic syndrome, and membranous GN. It may reapidly worsen to kidney failure.

Lupus nephritis affects approximately 3 out of every 10,000 people. In children with SLE, about half will have some form or degree of kidney involvement.

More than half of patients have not had other symptoms of SLE when they are diagnosed with lupus nephritis.

SLE is most common in women ages 20 - 40. For more information, see: systemic lupus erythematosus.

Symptoms

Symptoms of lupus nephritis include:

• Blood in the urine
• Foamy appearance to urine
• High blood pressure
• Swelling of any area of the body

For general lupus symptoms, see the article on SLE.

Signs and tests

A physical exam shows signs of decreased kidney functioning with edema. Blood pressure may be high. Abnormal sounds may be heard when the doctor listens to the heart and lungs, indicating fluid overload.

Tests that may be done include:

• ANA titer
• BUN and creatinine
• Lupus test
• Urinalysis
• Urine immunoglobulin light chain

A kidney biopsy is not used to diagnose lupus nephritis, but to determine what treatment is appropriate.

This disease may also affect the results of the following tests:

• Complement component 3
• Complement
• Syphilis test

Treatment

The goal of treatment is to improve kidney function. Medicines may include corticosteroids or other medications that suppress the immune system, such as cyclophosphamide, mycophenolate mofetil, or azathioprine.

You may need dialysis to control symptoms of kidney failure. A kidney transplant may be recommended. (People with active lupus should not have a transplant.)

Expectations (prognosis)

The outcome varies depending on the specific form of lupus nephritis. Patients may have acute flare-ups with alternating symptom-free periods.

Some cases of lupus nephritis may progress to chronic kidney failure.

Although lupus nephritis may return in a transplanted kidney, it rarely leads to end-stage kidney disease.

Complications

• Acute renal failure
• Chronic renal failure
• End-stage renal disease
• Nephrotic syndrome

Calling your health care provider

Call your health care provider if you have blood in the urine or swelling of your body.

If you have lupus nephritis, call your health care provider if you notice decreased urine output.

Prevention

There is no known prevention for lupus nephritis.

References

Nelson EG. Tubulointerstitial diseases. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 123.

Harris ED. Budd RC, Genovese MC, Firestein GS, Sargent JS, Sledge CB. Kelley's Textbook of Rheumatology. 7th ed. St. Louis, Mo: WB Saunders; 2005.