Lupus, formally known as systemic lupus erythematosus (SLE), is a chronic autoimmune disease where the body’s immune system mistakenly attacks its own healthy tissues and organs. This leads to widespread inflammation. It can affect various body systems. Individuals with lupus often experience periods of increased disease activity, called flares, and times of remission where symptoms lessen or disappear.
What Is Lupus Nephritis
Lupus nephritis is inflammation of the kidneys caused by systemic lupus erythematosus (SLE). In this condition, the immune system produces autoantibodies that incorrectly target kidney structures. These autoantibodies, along with other immune components, form immune complexes that deposit within the glomeruli, the kidneys’ tiny filtering units. The accumulation of these immune complexes triggers an inflammatory response, damaging the filters and surrounding kidney tissue. This inflammation impairs the kidneys’ ability to effectively filter waste products from the blood and regulate fluid balance, potentially leading to a decline in kidney function.
Symptoms of Kidney Involvement
When lupus affects the kidneys, several signs and symptoms can appear. Swelling (edema) often occurs in the legs, ankles, or around the eyes due to fluid retention. Foamy or bubbly urine suggesting excessive protein in the urine (proteinuria). Urine may also appear dark or reddish, indicating blood (hematuria).
Unexplained weight gain can result from fluid accumulation. High blood pressure is another common symptom, which the kidneys help regulate.
The Diagnostic Process
Diagnosing lupus nephritis involves tests to evaluate kidney function and identify the extent of kidney involvement. Urine tests detect abnormalities like elevated protein and red blood cells. Blood tests also measure waste products like creatinine and urea nitrogen, which accumulate when kidney function is impaired. These tests also estimate the glomerular filtration rate (eGFR), indicating kidney filtering efficiency.
A kidney biopsy is the definitive diagnostic tool. A small tissue sample is extracted from the kidney using a needle, allowing pathologists to examine it under a microscope. This provides information about inflammation, glomerular damage, and lupus nephritis classification, which guides treatment.
Treatment Approaches for Lupus Nephritis
Treatment for lupus nephritis aims to reduce inflammation, suppress the immune system, and prevent further damage to the kidneys. Corticosteroids, such as prednisone, are often prescribed to decrease inflammation. Immunosuppressants are also used to temper the immune system’s attack on the kidneys; common examples include mycophenolate mofetil, cyclophosphamide, and azathioprine.
These medications work by inhibiting the proliferation and function of immune cells responsible for the autoimmune response. Newer targeted therapies, such as calcineurin inhibitors like voclosporin and tacrolimus, or biologics like belimumab, may also be used. These agents offer more specific ways to modulate the immune system, often in combination with other immunosuppressants.
Treatment also involves managing complications. Angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) are prescribed to control high blood pressure and reduce protein leakage into the urine. Diuretics help eliminate excess fluid, reducing swelling. The specific combination and dosage of medications are tailored to the individual patient, considering the severity of their condition and their response to therapy.
Managing the Condition and Patient Outlook
Managing lupus nephritis is a long-term endeavor that requires continuous monitoring and adherence to a care plan. Regular follow-up appointments with healthcare providers are necessary to assess kidney function, monitor medication effectiveness, and adjust treatments. Lifestyle modifications also support managing the condition. Dietary changes, such as reducing sodium intake, are often recommended to help control blood pressure and minimize fluid retention.
In some cases, limiting protein intake may also be advised to reduce the workload on the kidneys. Lupus nephritis is a chronic condition, meaning it requires ongoing management throughout a person’s life. However, with advancements in modern treatments, many individuals can prevent severe kidney damage and maintain good kidney function for extended periods.
Despite these positive outcomes, there remains a potential for progression to chronic kidney disease (CKD) or, in some instances, end-stage kidney failure. Should kidney function significantly decline, interventions such as dialysis, which filters the blood artificially, or a kidney transplant, may become necessary. The goal of ongoing management and early, aggressive treatment is to minimize these risks and preserve kidney health, allowing individuals to lead full and active lives.