Lupus and the Urinary System

posted in Lupus Encyclopedia: The Book on July 16, 2024 by

Updated January 5, 2025

Excerpt from Chapter 12 of “The Lupus Encyclopedia”

“Monitoring the urinary system, particularly the kidneys, is important in SLE. This is because the start of nephritis (kidney inflammation) is usually asymptomatic (you feel fine even though there is active inflammation). Nephritis varies by ethnicity. It occurs in 25% to 40% of Caucasian SLE patients and in around 50% of African American, Asian, Pacific Islander, and Hispanic SLE patients. Afro-Caribbean SLE patients develop nephritis close to 80% of the time. Other factors also increase the risk of this serious complication.”
The Lupus Encyclopedia (2nd ed.), p. 239

The Urinary System and Lupus

The urinary system consists of the kidneys, ureters, bladder, and urethra. Its primary function is to filter waste products from the blood and excrete them as urine. Lupus can cause inflammation in various parts of this system, most commonly affecting the kidneys, leading to a condition known as lupus nephritis. According to “The Lupus Encyclopedia,” monitoring the urinary system, particularly the kidneys, is crucial in SLE.

Symptoms of Lupus Nephritis

Lupus nephritis can manifest in various ways, often silently progressing until significant damage occurs. Common symptoms include foamy urine due to excess protein, blood in the urine, high blood pressure, swelling in the legs, ankles, or feet, and unexplained weight gain. It is essential to recognize these symptoms early and seek medical advice to prevent further complications.

Diagnosis of Lupus Nephritis

Diagnosing lupus nephritis involves a combination of blood tests, urine tests, and sometimes a kidney biopsy. Blood tests typically check for elevated levels of creatinine and urea, indicating reduced kidney function. Urine tests look for proteinuria (excess protein in the urine) and hematuria (blood in the urine) to check for lupus in the urinary system.

The most important test is looking for proteinuria, which occurs in 100% of people with lupus nephritis. We want to identify proteinuria in the earliest stages, before the patient notices any problems. If caught early, remission with treatment is much more likely.

The best way to measure proteinuria is by getting a 1st or 2nd urine sample of the day and measuring the protein to creatinine ratio (UPCR). Lupus management guidelines recommend checking a UPCR every 6 to 12 months in all SLE patients. Many lupus experts recommend checking a UPCR every 3 months in most patients. Blood tests for lupus disease activity should also be checked, including anti-dsDNA, C3, C4, EC4d, anti-C1q, complete blood cell counts, liver enzymes, and kidney function.

Knowing how to collect an accurate urine sample is important for all SLE patients.

A kidney biopsy, where a small sample of kidney tissue is examined under a microscope, should be done as soon as proteinuria is noted. Lupus management guidelines recommend that a biopsy be done on patients who have a urine protein to creatinine ratio of 500 mg/mg or higher. Lower levels of proteinuria that are associated with high anti-dsDNA, low C3, low C4, or high EC4d should also prompt considerations for a biopsy.

Risk Factors for Lupus Nephritis

Lupus nephritis varies by ethnicity. It occurs in 25% to 40% of Caucasian SLE patients and in around 50% of African American, Asian, Pacific Islander, and Hispanic SLE patients. Afro-Caribbean SLE patients develop nephritis close to 80% of the time. Other factors that increase the risk of this serious complication include genetic predisposition, high disease activity, certain autoantibodies (like anti-Smith, anti-dsDNA, and anti-C1q), and other labs like high EC4d or low C3 or C4. It is essential for patients and healthcare providers to be aware of these risk factors to manage the disease effectively.

Treatment and Management of Lupus and the Urinary System

Treating lupus nephritis typically involves medications to reduce inflammation and suppress the immune system. Common treatments include corticosteroids, immunosuppressive drugs like cyclophosphamide or mycophenolate mofetil, and biologics such as rituximab.

2024 lupus nephritis management guidelines recommend that all patients should be on hydroxychloroquine. For the most severe types of lupus nephritis (proliferative nephritis), initial therapy should include belimumab (Benlysta) or a calcineurin inhibitor (CNI, like Lupkynis or tacrolimus). Doctor’s should prescribe these along with mycophenolate or cyclophosphamide and steroids. When doctors use this approach (called triple immunosuppressant therapy), the chances for complete remission and avoidance of end stage kidney disease are much higher compared to when Benlysta or a CNI are not initially included into therapy.

Alongside medication, lifestyle changes can play a crucial role in managing lupus nephritis. Maintaining a healthy diet, reducing salt intake, staying hydrated, and managing blood pressure are vital steps in preventing further kidney damage.

New Management Guidelines for Lupus Nephritis!

In 2024, the American College of Rheumatology announced new fantastic guidelines on how to better treat lupus nephritis. The recommendations are excellent. I give some highlights in this video below:

Monitoring and Follow-Up

Regular monitoring and follow-up with a healthcare provider are essential for managing lupus nephritis. Patients should have routine blood and urine tests to check kidney function and detect any signs of worsening inflammation. Early detection and prompt treatment of flares can help preserve kidney function and improve long-term outcomes.

Lifestyle and Support

Living with lupus and managing lupus nephritis can be challenging, but support is available. Patients can benefit from joining support groups, seeking counseling, and working closely with their healthcare team. Education about the disease and its management empowers patients to take an active role in their care.

Lupus significantly impacts the urinary system, particularly the kidneys, leading to lupus nephritis. Early recognition of symptoms, timely diagnosis, and effective management are crucial to preserving kidney function. It can help in improving the quality of life for lupus patients. By understanding the risks and taking proactive steps, individuals with lupus can better manage their condition. Taking proper action reduces the likelihood of severe complications. Regular monitoring, medication adherence, lifestyle modifications, and support from healthcare providers and communities are key components in the successful management of lupus nephritis.

For more in-depth information on Lupus and the Urinary System:

Read chapter 12 of The Lupus Encyclopedia, edition 2

Look up your symptoms, conditions, and medications in the Index of The Lupus Encyclopedia

If you enjoy the information from The Lupus Encyclopedia, please click the “SUPPORT” button at the top of the page to learn how you can help.

What are your comments and opinions?

If you have lupus, what has your experience been? What do you recommend for other patients?

Do you have any questions to ask Dr. Thomas?

Please click on “Leave a Comment” above to comment.

Please support “The Lupus Encyclopedia” blog post page

Click on “SUPPORT” at the top of the page to learn how you can support “The Lupus Encyclopedia“

No comment yet, add your voice below!

EMPOWERING PATIENTS

Lupus and the Urinary System

Excerpt from Chapter 12 of “The Lupus Encyclopedia”