Lupus nephritis

Lupus nephritis
Type IV lupus nephritis: The classic "flea-bitten" appearance of the cortical surface in the diffuse proliferative glomerulonephritides. (Courtesy of Ed Uthman, MD)]]
ICD-10	N08.5
ICD-9	583.81
MedlinePlus	000481
MeSH	D008181

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2] Ujjwal Rastogi, MBBS [3]; Raviteja Guddeti, M.B.B.S. [4]

Overview

Lupus nephritis is an inflammation of the kidney caused by systemic lupus erythematosus (SLE), a disease of the immune system. Apart from the kidneys, SLE can also damage the skin, joints, nervous system and virtually any organ or system in the body.

Classification

The World Health Organization has divided lupus nephritis into five classes based on the biopsy.

• Class I is histologically normal and does not show any evidence of disease.
• Class II is based on a finding of mesangial lupus nephritis
• Class III is focal proliferative nephritis
• Class IV is diffuse proliferative nephritis
• Class V is membranous nephritis and is characterized by extreme edema and protein loss.
• Class VI Glomerulosclerosis

Pathophysiology

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.

Differentiating from other Diseases

Diseases with similar symptoms are

• Chronic glomerulonephritis
• Polyarteritis nodosa
• Wegener granulomatosis

Natural History, Complications and Prognosis

Natural History

Lupus nephritis may damage different parts of the kidney. Class I has normal histology and does not show any evidence of disease and class V shows an extensive disease.

Complications

Possible complications include:

• Interstitial nephritis
• Nephrotic syndrome
• Membranous glomerulonephritis
• Kidney failure - acute and chronic
• End steg renal disease

Prognosis

• Prognosis depends on the specific form of lupus nephritis. Patients may have flare-ups in between symptom free intervals.
• Although lupus nephritis may return in a transplanted kidney, it rarely leads to end-stage kidney disease.

Diagnosis

Symptoms

Sufferers of lupus nephritis may or may not have symptoms of kidney disease, but it can manifest itself through:

• Weight gain
• Darker foamy urine
• swelling around the eyes, legs, ankles or fingers.

Furthermore, patients may suffer from other symptoms of lupus unrelated to kidney function. Such symptoms can include

• Arthritis - joint pains
• Fevers
• Gastro-intenstinal disturbances
• Headaches
• Fatigue
• Swollen joints

Physical Examination

Vitals

• Elevated body temperature
• high blood pressure

Eyes

• Peri-orbital puffiness can be noticed in patients with advanced disease having renal failure.

Extremities

• swelling around the legs, ankles or fingers.
• Swollen joints

Laboratory Findings

Tests that may be done include:

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

Chest X-ray

• Shows signs of fluid collection in the lungs in very severe cases.

Ultrasound

• Ultrasound scans of the kidneys

The diagnosis of lupus nephritis depends on blood tests, urinalysis, X-rays, ultrasound scans of the kidneys, and a kidney biopsy. Medicines which decrease swelling, lower blood pressure and decrease inflammation by suppressing the immune system. Patients may need to monitor intake of protein, sodium, and potassium. Patients with severe disease should restrict their sodium intake to 2 grams per day and limit fluid as well. Depending on the histology, renal function and degree of proteinuria, patients may require steroid therapy or chemotherapy regimens such as cyclophosphamide, azathioprine, mycophenolate mofetil or cyclosporine.

The medical therapy for lupus nephritis depends on the severity of the disease. For mild disease, corticosteroids are generally prescribed. More severe disease requires treatment with immunosuppressant agents. The two most commonly used agents are mycophenolate mofetil and intravenous cyclophosphamide. One recent study compared these two drugs. The authors showed that patients with Class III or IV disease are more likely to benefit from mycophenolate mofetil as compared to cyclophosphamide. As a result, mycophenolate mofetil is now considered to be the first-line therapy for this disease.

External links

• Lupus Nephritis Clinical Research Study
• London Lupus Centre - Treatment, Diagnosis, Research
• Lupus Foundation of America, Inc.
• Lupus Research Institute
• S.L.E. Lupus Foundation
• Lupus International