Alternative names
Nephritis - lupus; Lupus glomerular disease

Definition
Lupus nephritis is a kidney disorder that is a complication of systemic lupus erythematosus, characterized by damage to the glomerulus and progressive loss of kidney function.

Causes, incidence, and risk factors

Lupus nephritis is one complication of systemic lupus erythematosus (SLE). It is related to the autoimmune process of lupus, where the immune system produces antibodies (antinuclear antibody and others) against body components. Complexes of these antibodies and complement accumulate in the kidneys and result in an inflammatory response.

Lupus causes various disorders of the internal structures of the kidney, including interstitial nephritis, mesangial GN, membranous GN, membranoproliferative GN, diffuse proliferative GN, and others.

It often causes nephrotic syndrome (excessive protein excretion) and may progress rapidly to renal failure. There is progressive azotemia (the accumulation of nitrogenous waste products in the bloodstream) and urinary abnormalities including protein and blood in the urine.

Lupus nephritis affects approximately 3 out of 10,000 people. Systemic lupus erythematosus is most common in women, especially those 20 to 40 years old. It has a familial tendency, with a higher incidence in blacks. It may be related to other autoimmune disorders including rheumatoid arthritis and scleroderma. It has been known to be triggered by pregnancy in some cases.

In children with SLE, about half will have some form or degree of kidney involvement.

Symptoms

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

Symptoms of SLE may include the following:

 
• Joint pain  
• Joint swelling  
• Joint redness  
• Rash       o commonly on the face but may occur on other areas       o characteristic “butterfly” distribution  
• Chest pain, sharp and stabbing  
• Cough  
• Sun sensitivity       o fever may develop after exposure to sun       o rash may develop after exposure to sun  
• Fatigue  
• Mouth ulcers (painless)  
• Neurologic changes       o seizures       o dementia or psychosis

Signs and tests
Examination indicates decreased kidney functioning with edema and may indicate renal failure. Blood pressure may be high. Abnormal sounds may be heard on auscultation of the heart and lungs, indicating fluid overload. Lupus nephritis is usually discovered during investigation of the causes of reduced kidney function. Fewer than one-half have other symptoms of systemic lupus erythematosus at the time of diagnosis of lupus nephritis.

 
• A urinalysis is abnormal with protein, casts, and red blood cells present in the urine.  
• An ANA titer is high.  
• Syphilis tests may be falsely positive.  
• BUN and creatinine may be used to assess kidney functioning.  
• A lupus erythematosus (LE) cell test is positive.  
• A kidney biopsy is indicated, not to diagnose lupus nephritis, but to determine what treatment is appropriate for the renal component of SLE.  
• A urine immunoglobulin light chain is elevated.

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

 
• Complement component 3  
• Complement

Treatment
The goal of treatment is improvement of kidney function.

Corticosteroids or other immunosuppressive medications are often effective in reducing symptoms. Whether high doses of corticosteroids or immunosuppressives are likely to be beneficial depends on the precise findings on kidney biopsy.

Dialysis may be necessary to control symptoms of acute or chronic renal failure. Renal failure may be severe enough to require dialysis even if no other symptoms of SLE are present.

A kidney transplant may be recommended to treat kidney failure resulting from lupus nephritis.

Expectations (prognosis)
The outcome varies. It is usually worse with diffuse proliferative lupus nephritis (one specific form of the disorder). As with SLE, the course is variable, with exacerbations (acute episodes) and remissions (symptom-free periods).

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

Over 80% of people with lupus nephritis severe enough to require dialysis or transplantation will survive for more than 5 years after treatment. Although lupus nephritis may recur in a transplanted kidney, it rarely leads to end stage renal disease. People with active lupus should not undergo transplantation.

Complications

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

Calling your health care provider
Call your health care provider if blood in the urine or swelling of the body develops.

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

Prevention
There is no known prevention for lupus nephritis.

Medical Encyclopedia

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.