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รltima actualizaciรณn: 8/25/2023
Aรฑos publicados: 1988, 1989, 1996, 1998, 2000, 2005, 2019, 2023
NORD gratefully acknowledges Lawrence Slapcoff, MD, and Daniel C. Cattran, MD, Division of Nephrology, Department of Medicine, University Health Network, University of Toronto, for assistance in the preparation of this report.
Summary
IgA nephropathy is a kidney disease in which IgA, a protein meant to defend the body against foreign invaders, accumulates in the kidneys and damages them. This impairs their filtering function. As a result, the kidneys begin to let substances such as blood and protein leak into the urine.
This condition most often occurs in Caucasian and Asian males. It usually appears when people are in their teens to late 30โs but can occur at any age. Many cases resolve over time. However, in a subset of patients, the disease may not resolve and thus can lead to end-stage renal disease (ESRD) after 20-25 years. Rarely the condition can progress much more rapidly leading to renal failure within a few years, if not treated.
People who have this condition most often present with one or recurrent episodes of having blood in their urine (visible hematuria). These episodes usually occur during or right after an upper respiratory tract infection such as a cold, sore throat or a gastrointestinal infection.
Treatment includes drugs that aim to slow progression of the disease and others that aim to reduce inflammation. The choice of treatment is made based on a variety of factors including blood pressure, the amount of protein in the urine and the estimated kidney function.
Introduction
The kidneys are two fist sized organs located in the back under the rib cage that serve as a filter for blood. They remove excess fluid and waste as urine, while reabsorbing the proper amount of water and other chemicals that the body needs to function. The name IgA nephropathy comes from the fact that that the protein depositing in the kidney has the characteristics of a normal circulating immunoglobulin protein designated IgA. In the disease, the normal protein is changed somewhat causing it to deposit in the filters of the kidney and it to leak blood and or protein. It is also named Bergerโs disease as it was first described by Berger and Hinglais in 1968.
Patients with IgA nephropathy often present with:
โข red colored urine (visible hematuria)
โข pain in the sides of their back (flank pain)
โข swelling in the ankles
โข high blood pressure
When these symptoms are present during or directly after a respiratory infection such as a sore throat or a cold, there is a higher likelihood that the person has IgA nephropathy.
Some patients who have either the rapidly progressive type of IgA nephropathy or chronic asymptomatic disease may present with symptoms of end-stage renal disease (ESRD):
โข high blood pressure
โข little or no urination
โข edema
โข feeling tired
โข drowsiness
โข generalized itching or numbness
โข dry skin
โข headaches
โข weight loss
โข appetite loss
โข nausea
โข vomiting
โข sleep problems
โข trouble concentrating
โข darkened skin
โข muscle cramps
As mentioned above, the kidneys serve as filters for the blood. Each kidney consists of about 1 million โmini-filtersโ called nephrons.
Each nephron consists of a Bowmanโs capsule and tubules. The Bowmanโs capsule contains many important structures such as the glomerulus, which is a series of tiny blood vessels where the initial filtration takes place. Once the fluid has been filtered by the glomerulus, it travels along the tubules, where chemicals and water are either added or removed from the filtered fluid based on the bodyโs needs. Once the fluid has passed through the tubules, it leaves the body as urine.
For an unknown reason, patients with IgA nephropathy create abnormal IgA proteins that the body recognizes as foreign. As a result, the body attacks them, which leads to the formation of clusters of proteins called immune complexes. These immune complexes are what are deposited in the kidneys and causes damage. Due to this phenomenon, IgA nephropathy can be considered an autoimmune disease.
The IgA protein immune complexes specifically deposit in the central area of the glomerulus in the mesangial area. Once these immune complexes are deposited, the glomerulus (filter) become inflamed and damaged. As a result, their filtering function is damaged allowing substances such as red blood cells and proteins to pass through the damaged filter into the urine.
When patients have respiratory infections such as a cough or sore throat, IgA immune complexes are higher in circulation. Therefore, many of them end up depositing in the kidneys and this is when patients with IgA nephropathy typically present with symptoms such as hematuria (blood in the urine). Some patients may also experience episodes of IgA nephropathy when they have gastrointestinal infections such as in stomach flu or even after exercise.
There is evidence to suggest that genetic factors play a role in this disease. It has been suggested that IgA nephropathy is a complex polygenic disease meaning that there are many genes and environmental factors that contribute to an individual developing the condition.
In North America and Europe, males are two times more likely to get the disease, while in Asia, females are just as likely as males to be affected. In terms of ethnicity, Asians are much more likely than Caucasians who are, in turn, much more likely than black population to get IgA nephropathy. This disease most often presents between teenage years to late 30โs but can present at any age.
IgA nephropathy might be suspected when a patient has bloody (red) or dark urine following a respiratory tract illness such as a sore throat or a cold.
Although a doctor may have a high index of suspicion that their patient has IgA nephropathy based on history, physical exam, urine tests and blood tests, the only way to truly diagnose IgA nephropathy is through a kidney biopsy.
A kidney biopsy is when a small needle is inserted into a personโs kidney in order to take a small sample of tissue. This tissue is then examined under a microscope to look for certain characteristic markers of the disease.
Clinical Testing and Work-Up
Aside from the kidney biopsy, patients should expect to have regular blood and urine tests. For patients with mild disease (normal blood pressure, low amount of protein in urine), they can expect to have tests done every 6-12 months. Patients who have more severe forms of the disease can expect more regular monitoring.
Treatment
Unfortunately, there is not yet a cure for IgA nephropathy. However, many cases resolve on their own.
Treatment for this condition falls under two main categories:
Non-immunosuppressive drugs โ Those aimed at preventing progression of the disease.
Immunosuppressive drugs โ Those aimed at reducing inflammation.
The non-immunosuppressive drugs used are angiotensin converting enzyme inhibitors (ACE inhibitors) and angiotensin receptor blockers (ARBs). They help prevent progression of the disease through reducing the amount of protein that filters through the damaged glomerulus and enters the urine and by lowering blood pressure.
In 2021, budesonide (Tarpeyo) was approved by the U.S. Food and Drug Administration (FDA) to reduce urine protein level in adults with primary IgA nephropathy who are at risk of rapid disease progression.
In 2023, sparsentan (Filspari) a drug that combines an endothelin type A receptor antagonist with an angiotensin II type I receptor antagonist, was approved by the FDA for the treatment of IgA patients at high risk of progression.
Although still not FDA approved, there have been several articles showing the benefits of use of SGLT2 inhibitors in the treatment of patients with IgA nephropathy at high risk of progression.
The immunosuppressive drugs used most often are corticosteroids. They reduce inflammation by limiting the inflammatory response.
In summary treatment for IgA nephropathy falls under two categories:
Non-immunosuppressive
โข ACE inhibitors
โข ARBs
โข Sparsentan (combined Enothelin and ARB antagonist)
โข SGLT2 inhibitors
Immunosuppressive
โข corticosteroids (such as prednisone)
โข cyclophosphamide
Some patients may also be prescribed a statin, which is a cholesterol lowering drug given to lower the risk of developing cardiovascular disease.
Prevention
Diet and Nutrition
Although researchers have not found that diet and nutrition play a role in causing or preventing the disease, health care providers may recommend the following dietary changes to patients who have the condition to maximize their renal health:
โข limit dietary sodium
โข eating a diet low in saturated fat and cholesterol
Fish Oil โ The efficacy of fish oil in the treatment of IgA nephropathy has not yet been determined. There have been studies showing that taking fish oil supplements may provide very modest benefits.
Tonsillectomy โ Studies have shown tonsillectomies, even in patients without inflamed/infected tonsils, may provide significant benefit for patients with IgA nephropathy but more research must be done.
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Toll-free: (800) 411-1222
TTY: (866) 411-1010
Email: [email protected]
Some current clinical trials also are posted on the following page on the NORD website:
https://rarediseases.org/for-patients-and-families/information-resources/info-clinical-trials-and-research-studies/
For information about clinical trials sponsored by private sources, in the main, contact:
www.centerwatch.com
For more information about clinical trials conducted in Europe, contact:
https://www.clinicaltrialsregister.eu/
JOURNAL ARTICLES
Wheeler DC, Toto RD, Stefรกnsson BV, Jongs N, Chertow GM, Greene T, Hou FF, McMurray JJV, Pecoits-Filho R, Correa-Rotter R, Rossing P, Sjรถstrรถm CD, Umanath K, Langkilde AM, Heerspink HJL; DAPA-CKD Trial Committees and Investigators. A pre-specified analysis of the DAPA-CKD trial demonstrates the effects of dapagliflozin on major adverse kidney events in patients with IgA nephropathy. Kidney Int. 2021 Jul;100(1):215-224. doi: 10.1016/j.kint.2021.03.033. Epub 2021 Apr 18. PMID: 33878338.
Liu LL, Wang LN, Jiang Y, et al. Tonsillectomy for IgA nephropathy: a meta-analysis. Am J Kidney Dis. 2015;65(1):80-87. doi:10.1053/j.ajkd.2014.06.036 Wyatt RJ, Julian BA. IgA nephropathy. New England Journal of Medicine. 2013;368(25):2402โ2414.
Reid S, Cawthon PM, Craig JC, Samuels JA, Molony DA, Strippoli GF. Non-immunosuppressive treatment for IgA nephropathy. Cochrane Database Syst Rev. 2011;(3):CD003962. Published 2011 Mar 16. doi:10.1002/14651858.CD003962.pub2
INTERNET
Cattran DC and Appel GB. Treatment and prognosis of IgA nephropathy. UpToDate. Updated Jul 28, 2023. https://www.uptodate.com/contents/treatment-and-prognosis-of-iga-nephropathy.Accessed Aug 24, 2023.
IgA Nephropathy (Bergerโs Disease). Mayo Clinic. Published June 09, 2023. https://www.mayoclinic.org/diseases-conditions/iga-nephropathy/symptoms-causes/syc-20352268. Accessed Aug 24, 2023.
IgA Nephropathy. National Institute of Diabetes and Digestive and Kidney Diseases. Last Reviewed September 2022.https://www.niddk.nih.gov/health-information/kidney-disease/iga-nephropathy. Accessed Aug 24, 2023.
Cheung CK and Barratt J. Pathogenesis of IgA nephropathy. UpToDate. Updated Nov 28, 2022.https://www.uptodate.com/contents/clinical-presentation-and-diagnosis-of-iga-nephropathy. Accessed Aug 24, 2023.
Cheung CK and Barratt J. Clinical presentation and diagnosis of IgA nephropathy. UpToDate. Updated Nov 28, 2022. https://www.uptodate.com/contents/clinical-presentation-and-diagnosis-of-iga-nephropathy. Accessed Aug 24, 2023.
Salim SA. IgA Nephropathy. Medscape. Dec 24, 2021. https://emedicine.medscape.com/article/239927-overview. Accessed Aug 24, 2023.
Latif W. IgA Nephropathy. Medline. Review Date Review Date 7/27/2021. www.nlm.nih.gov/medlineplus/ency/article/000466.htm. Accessed Aug 24, 2023.
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Orphanet has a summary about this condition that may include information on the diagnosis, care, and treatment as well as other resources. Some of the information and resources are available in languages other than English. The summary may include medical terms, so we encourage you to share and discuss this information with your doctor. Orphanet is the French National Institute for Health and Medical Research and the Health Programme of the European Union.
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