Kidney Involvement
Lupus is an autoimmune disease that can affect almost any part
of your body, most often your joints, skin, kidneys, heart, lungs, blood, or
brain. Your two kidneys are part of your renal system, which also includes two
ureters, the bladder, and the urethra.
As the primary organs of the renal system, your kidneys are responsible for:
Lupus Nephritis
Inflammation of the nephrons, the structures within the
kidneys that filter the blood, is called glomerulonephritis, or nephritis.
Lupus nephritis is the term used when lupus causes inflammation in your
kidneys, making them unable to properly remove waste from your blood or control
the amount of fluids in your body. Abnormal levels of waste can build up in the
blood, and edema (swelling) can develop. Left untreated, nephritis can lead to
scarring and permanent damage to the kidneys and possibly end-stage renal
disease (ESRD). People with ESRD need regular filtering of their body’s waste
done by a machine (dialysis) or a kidney transplant so that at least one kidney
is working properly.
Lupus nephritis most often develops within the first five
years after the symptoms of lupus start, and usually affects people between the
ages of 20 and 40. It is estimated that as many as 40 percent of all people
with lupus, and as many as two-thirds of all children with lupus, will develop
kidney complications that require medical evaluation and treatment. Because
there are so few symptoms of kidney disease, significant damage to your kidneys
can happen before you are diagnosed with lupus.
In the early stages of lupus nephritis, there are very few
signs that anything is wrong. Often the first symptoms of lupus nephritis are
weight gain and puffiness in your feet, ankles, legs, hands, and/or eyelids.
This swelling often becomes worse throughout the day. Also, your urine may be
foamy or frothy, or have a red color. Often the first signs of lupus nephritis
show up in clinical laboratory tests on the urine. That is why testing your
urine is so important.
Nephrologists are the physicians who treat the renal system.
The tests they will use to diagnose lupus nephritis are: collection of urine,
usually over a 24-hour period; blood tests; and often, a kidney
biopsy.
Symptoms of Lupus Nephritis
Urinalysis
Because your body’s waste matter is processed by your kidneys,
testing a sample of your urine can show any problems with the way your kidneys
are functioning. The most common tests look for cell casts (fragments of cells
normally found in the blood, or fragments of the tubules of the kidneys) and
proteinuria (protein being spilled into your body because your kidneys are not
filtering the waste properly).
Blood Tests
Certain blood tests can provide information about kidney
damage and how well your body is filtering waste. The creatinine blood test is
usually ordered along with a blood urea nitrogen (BUN) test to assess kidney
function. A combination of blood and urine creatinine levels may be used to
calculate a creatinine clearance. This measures how effectively your kidneys
are filtering small molecules like creatinine out of your blood. Serum
creatinine measurements (along with your age, weight, and gender) are used to
calculate the estimated glo-merular filtration rate (EGFR), which is used as a
screening test for evidence of kidney damage.
Kidney Biopsy
A kidney biopsy is done in a hospital. While you lie on your
stomach your nephrologist will insert a very thin, long needle through the skin
of your back and remove a tiny piece of tissue from one of your kidneys. The
tissue will be examined under a microscope to determine how much inflammation
or scarring is present.
Treatments
Even though lupus nephritis is among the more serious
complications of lupus, there are effective treatments. Prednisone and other
corticosteroids are generally prescribed to stop the inflammation.
Immunosuppressive drugs may also be used (with or in place of steroid
treatments), such as cyclophosphamide (Cytoxan®), azathioprine (Imuran®),
cyclosporin A, and mycophenolate mofetil (CellCept®). Medications developed for
other illnesses are also being studied as treatments for lupus nephritis,
including rituximab (Rituxan®), and eculizuimab (Soliris™).
Most people who develop lupus nephritis will live a normal
lifespan as long as they continue to receive proper treatment.
Other Lupus-Related Kidney Disorders
Not all kidney problems in people with lupus are due to lupus
nephritis.
All of these complications can be treated, so if you develop
any new symptoms, contact your doctor promptly.
This information comes from the Lupus Foundation of America.
of your body, most often your joints, skin, kidneys, heart, lungs, blood, or
brain. Your two kidneys are part of your renal system, which also includes two
ureters, the bladder, and the urethra.
As the primary organs of the renal system, your kidneys are responsible for:
- maintaining the correct amount and type of body fluids
- getting rid of waste products and toxic substances
- regulating the hormones (chemical messengers) that help control blood
pressure and blood volume
Lupus Nephritis
Inflammation of the nephrons, the structures within the
kidneys that filter the blood, is called glomerulonephritis, or nephritis.
Lupus nephritis is the term used when lupus causes inflammation in your
kidneys, making them unable to properly remove waste from your blood or control
the amount of fluids in your body. Abnormal levels of waste can build up in the
blood, and edema (swelling) can develop. Left untreated, nephritis can lead to
scarring and permanent damage to the kidneys and possibly end-stage renal
disease (ESRD). People with ESRD need regular filtering of their body’s waste
done by a machine (dialysis) or a kidney transplant so that at least one kidney
is working properly.
Lupus nephritis most often develops within the first five
years after the symptoms of lupus start, and usually affects people between the
ages of 20 and 40. It is estimated that as many as 40 percent of all people
with lupus, and as many as two-thirds of all children with lupus, will develop
kidney complications that require medical evaluation and treatment. Because
there are so few symptoms of kidney disease, significant damage to your kidneys
can happen before you are diagnosed with lupus.
In the early stages of lupus nephritis, there are very few
signs that anything is wrong. Often the first symptoms of lupus nephritis are
weight gain and puffiness in your feet, ankles, legs, hands, and/or eyelids.
This swelling often becomes worse throughout the day. Also, your urine may be
foamy or frothy, or have a red color. Often the first signs of lupus nephritis
show up in clinical laboratory tests on the urine. That is why testing your
urine is so important.
Nephrologists are the physicians who treat the renal system.
The tests they will use to diagnose lupus nephritis are: collection of urine,
usually over a 24-hour period; blood tests; and often, a kidney
biopsy.
Symptoms of Lupus Nephritis
- Sudden and unexplained swelling, especially in the
extremities (feet, ankles, legs, fingers, arms) or the eyes. - Blood in the urine.
- Elevated blood pressure.
- Foamy appearance in urine.
- Increased urination, especially at night.
Urinalysis
Because your body’s waste matter is processed by your kidneys,
testing a sample of your urine can show any problems with the way your kidneys
are functioning. The most common tests look for cell casts (fragments of cells
normally found in the blood, or fragments of the tubules of the kidneys) and
proteinuria (protein being spilled into your body because your kidneys are not
filtering the waste properly).
Blood Tests
Certain blood tests can provide information about kidney
damage and how well your body is filtering waste. The creatinine blood test is
usually ordered along with a blood urea nitrogen (BUN) test to assess kidney
function. A combination of blood and urine creatinine levels may be used to
calculate a creatinine clearance. This measures how effectively your kidneys
are filtering small molecules like creatinine out of your blood. Serum
creatinine measurements (along with your age, weight, and gender) are used to
calculate the estimated glo-merular filtration rate (EGFR), which is used as a
screening test for evidence of kidney damage.
Kidney Biopsy
A kidney biopsy is done in a hospital. While you lie on your
stomach your nephrologist will insert a very thin, long needle through the skin
of your back and remove a tiny piece of tissue from one of your kidneys. The
tissue will be examined under a microscope to determine how much inflammation
or scarring is present.
Treatments
Even though lupus nephritis is among the more serious
complications of lupus, there are effective treatments. Prednisone and other
corticosteroids are generally prescribed to stop the inflammation.
Immunosuppressive drugs may also be used (with or in place of steroid
treatments), such as cyclophosphamide (Cytoxan®), azathioprine (Imuran®),
cyclosporin A, and mycophenolate mofetil (CellCept®). Medications developed for
other illnesses are also being studied as treatments for lupus nephritis,
including rituximab (Rituxan®), and eculizuimab (Soliris™).
Most people who develop lupus nephritis will live a normal
lifespan as long as they continue to receive proper treatment.
Other Lupus-Related Kidney Disorders
Not all kidney problems in people with lupus are due to lupus
nephritis.
- Infections of the urinary tract, causing frequent urination
or burning when urinating, are quite common. - Fluid retention or even loss of kidney function can be a side
effect of non-steroidal anti-inflammatory drugs (NSAIDs) and medications such
as aspirin. - Interstitial nephritis, which is inflammation of the
connective tissue inside the glomerulus, can be a side effect of
anti-inflammatory medications or antibiotics. - Thrombosis and vasculitis, two blood-related lupus symptoms,
can damage the kidneys and may even cause kidney failure. - Lupus cystitis, which is inflammation of the lining of the
bladder, may cause frequent urination and is associated with abdominal
discomfort, including vomiting and weight loss. - Medications used to treat lupus may cause signs or symptoms
of kidney disease that can be confused with lupus nephritis.
All of these complications can be treated, so if you develop
any new symptoms, contact your doctor promptly.
This information comes from the Lupus Foundation of America.