Source: Mayo Clinic
Lupus nephritis is a type of kidney inflammation. It's a common complication in people who have systemic lupus erythematosus — more commonly known as lupus.
Lupus is an autoimmune disease in which your immune system produces proteins called autoantibodies that attack your own tissues and organs.
Lupus nephritis occurs when lupus autoantibodies affect structures in your kidneys that filter out waste. This causes kidney inflammation and may lead to blood in the urine (hematuria), protein in the urine (proteinuria), high blood pressure, impaired kidney function or even kidney failure.
Diagnosing lupus is difficult because signs and symptoms vary considerably from person to person. Signs and symptoms of lupus may vary over time and overlap with those of many other disorders.
No one test can diagnose lupus. The combination of blood and urine tests, signs and symptoms, and physical examination findings leads to the diagnosis.
Blood and urine tests may include:
- Complete blood count. This test measures the number of red blood cells, white blood cells and platelets as well as the amount of hemoglobin, a protein in red blood cells. Results may indicate you have anemia, which commonly occurs in lupus. A low white blood cell or platelet count may occur in lupus as well.
- Erythrocyte sedimentation rate. This blood test determines the rate at which red blood cells settle to the bottom of a tube in an hour. A faster than normal rate may indicate a systemic disease, such as lupus. The sedimentation rate isn't specific for any one disease. It may be elevated if you have lupus, an infection, another inflammatory condition or cancer.
- Kidney and liver assessment. Blood tests can assess how well your kidneys and liver are functioning. Lupus can affect these organs. Urinalysis. An examination of a sample of your urine may show an increased protein level or red blood cells in the urine, which may occur if lupus has affected your kidneys.
- Antinuclear antibody (ANA) test.A positive test for the presence of these antibodies — produced by your immune system — indicates a stimulated immune system. While most people with lupus have a positive ANA test, most people with a positive ANA do not have lupus. If you test positive for ANA, your doctor may advise more-specific antibody testing.
If your doctor suspects that lupus is affecting your lungs or heart, he or she may suggest:
- Chest X-ray. An image of your chest may reveal abnormal shadows that suggest fluid or inflammation in your lungs.
- Echocardiogram. This test uses sound waves to produce real-time images of your beating heart. It can check for problems with your valves and other portions of your heart.
Lupus can harm your kidneys in many different ways, and treatments can vary, depending on the type of damage that occurs. In some cases, it's necessary to test a small sample of kidney tissue to determine what the best treatment might be. The sample can be obtained with a needle or through a small incision.
Skin biopsy is sometimes performed to confirm a diagnosis of lupus affecting the skin.
Treatment for lupus depends on your signs and symptoms. Determining whether your signs and symptoms should be treated and what medications to use requires a careful discussion of the benefits and risks with your doctor.
As your signs and symptoms flare and subside, you and your doctor may find that you'll need to change medications or dosages. The medications most commonly used to control lupus include:
- Nonsteroidal anti-inflammatory drugs (NSAIDs). Over-the-counter NSAIDs, such as naproxen sodium (Aleve) and ibuprofen (Advil, Motrin IB, others), may be used to treat pain, swelling and fever associated with lupus. Stronger NSAIDs are available by prescription. Side effects of NSAIDs include stomach bleeding, kidney problems and an increased risk of heart problems.
- Antimalarial drugs. Medications commonly used to treat malaria, such as hydroxychloroquine (Plaquenil), affect the immune system and can help decrease the risk of lupus flares. Side effects can include stomach upset and, very rarely, damage to the retina of the eye. Regular eye exams are recommended when taking these medications.
- Corticosteroids. Prednisone and other types of corticosteroids can counter the inflammation of lupus. High doses of steroids such as methylprednisolone (A-Methapred, Medrol) are often used to control serious disease that involves the kidneys and brain. Side effects include weight gain, easy bruising, thinning bones (osteoporosis), high blood pressure, diabetes and increased risk of infection. The risk of side effects increases with higher doses and longer term therapy.
- Immunosuppressants. Drugs that suppress the immune system may be helpful in serious cases of lupus. Examples include azathioprine (Imuran, Azasan), mycophenolate mofetil (CellCept) and methotrexate (Trexall). Potential side effects may include an increased risk of infection, liver damage, decreased fertility and an increased risk of cancer.
- Biologics. A different type of medication, belimumab (Benlysta) administered intravenously, also reduces lupus symptoms in some people. Side effects include nausea, diarrhea and infections. Rarely, worsening of depression can occur.
- Rituximab (Rituxan) can be beneficial in cases of resistant lupus. Side effects include allergic reaction to the intravenous infusion and infections.
Lifestyle and home remedies
Take steps to care for your body if you have lupus. Simple measures can help you prevent lupus flares and, should they occur, better cope with the signs and symptoms you experience. Try to:
- See your doctor regularly. Having regular checkups instead of only seeing your doctor when your symptoms worsen may help your doctor prevent flare-ups, and can be useful in addressing routine health concerns, such as stress, diet and exercise that can be helpful in preventing lupus complications.
- Be sun smart. Because ultraviolet light can trigger a flare, wear protective clothing — such as a hat, long-sleeved shirt and long pants — and use sunscreens with a sun protection factor (SPF) of at least 55 every time you go outside.
- Get regular exercise. Exercise can help keep your bones strong, reduce your risk of heart attack and promote general well-being.
- Don't smoke. Smoking increases your risk of cardiovascular disease and can worsen the effects of lupus on your heart and blood vessels.
- Eat a healthy diet. A healthy diet emphasizes fruits, vegetables and whole grains. Sometimes you may have dietary restrictions, especially if you have high blood pressure, kidney damage or gastrointestinal problems.
- Ask your doctor if you need vitamin D and calcium supplements. There is some evidence to suggest that people with lupus may benefit from supplemental vitamin D. A 1,200- to 1,500-milligram calcium supplement taken daily may help keep your bones healthy.