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Home , Chronic kidney disease, Glomerulosclerosis, Kidney disease, Kidney failure, Nephrotic syndrome

Glomerular

National and Urologic Diseases Information Clearinghouse

Many diseases affect kidney function by Blood enters the kidneys through arteries attacking the glomeruli, the tiny units that branch inside the kidneys into tiny ­within the kidney where blood is cleaned. clusters of looping blood vessels. Each Glomerular diseases include many cluster is called a , which comes conditions with a variety of genetic and from the Greek word meaning filter. The environmental causes, but they fall into two plural form of the word is glomeruli. There major categories: are approximately 1 million glomeruli, or filters, in each kidney. The glomerulus is • (gloh-MEHR- attached to the opening of a small fluid- yoo-loh-nef-RY-tis) describes the collecting tube called a tubule. Blood is of the membrane tissue filtered in the glomerulus, and extra fluid in the kidney that serves as a filter, and wastes pass into the tubule and become separating wastes and extra fluid from . Eventually, the urine drains from the blood. the kidneys into the bladder through larger • (gloh-MEHR- tubes called ureters. yoo-loh-skleh-ROH-sis) describes the scarring or hardening of the tiny blood vessels within the kidney. Filtered blood Blood with Although glomerulonephritis and wastes glomerulosclerosis have different causes, they can both lead to .

What are the kidneys and what do they do? The two kidneys are bean-shaped organs located just below the rib cage, one on each side of the spine. Every day, the two Glomerulus kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of Wastes (urine) urine, composed of wastes and extra fluid. to the bladder

In the (left), tiny blood vessels intertwine with fluid-collecting tubes. Each kidney contains Tubule about 1 million Nephron . Each glomerulus-and-tubule unit is called What are the symptoms of a nephron. Each kidney is composed of about 1 million nephrons. In healthy glomerular ? nephrons, the glomerular membrane that The of glomerular separates the from the tubule ­disease include allows waste products and extra to • : large amounts of pass into the tubule while keeping blood in the urine cells and protein in the bloodstream. • : blood in the urine How do glomerular diseases • reduced glomerular filtration rate: interfere with kidney inefficient filtering of wastes from the function? blood Glomerular diseases damage the glomeruli, • : low blood protein letting protein and sometimes red blood cells leak into the urine. Sometimes a • : swelling in parts of the body glomerular disease also interferes with One or more of these symptoms can be the the clearance of waste products by the first sign of . But how would kidney, so they begin to build up in the you know, for example, whether you have blood. Furthermore, loss of blood proteins ? Before seeing a doctor, you like in the urine can result in a may not. But some of these symptoms have fall in their level in the bloodstream. In signs, or visible manifestations: normal blood, albumin acts like a sponge, drawing extra fluid from the body into the • Proteinuria may cause foamy urine. bloodstream, where it remains until the kidneys remove it. But when albumin leaks • Blood may cause the urine to be pink into the urine, the blood loses its capacity or cola-colored. to absorb extra fluid from the body. Fluid can accumulate outside the circulatory • Edema may be obvious in hands and system in the face, hands, feet, or ankles ankles, especially at the end of the day, and cause swelling. or around the eyes when awakening in the morning, for example.

2 Glomerular Diseases How is glomerular disease What causes glomerular diagnosed? disease? Patients with glomerular disease have A number of different diseases can result significant amounts of protein in the urine, in glomerular disease. It may be the direct which may be referred to as “nephrotic result of an or a toxic to the range” if levels are very high. Red blood kidneys, or it may result from a disease cells in the urine are a frequent finding that affects the entire body, like or as well, particularly in some forms of . Many different kinds of diseases can glomerular disease. Urinalysis provides cause swelling or scarring of the nephron or information about kidney damage by glomerulus. Sometimes glomerular disease indicating levels of protein and red blood is idiopathic, meaning that it occurs without cells in the urine. Blood tests measure the an apparent associated disease. levels of waste products such as and to determine whether the The categories presented below can filtering capacity of the kidneys is impaired. overlap: that is, a disease might belong If these lab tests indicate kidney damage, to two or more of the categories. For the doctor may recommend ultrasound example, is a form or an x ray to see whether the shape or of glomerular disease that can be placed size of the kidneys is abnormal. These in two categories: systemic diseases, since tests are called renal imaging. But since diabetes itself is a systemic disease, and glomerular disease causes problems at the sclerotic diseases, because the specific cellular level, the doctor will probably also damage done to the kidneys is associated recommend a kidney biopsy—a procedure with scarring. in which a needle is used to extract small pieces of tissue for examination with Autoimmune Diseases different types of microscopes, each of When the body’s immune system functions which shows a different aspect of the tissue. properly, it creates protein-like substances A biopsy may be helpful in confirming called and immunoglobulins glomerular disease and identifying the to protect the body against invading cause. organisms. In an , the immune system creates autoantibodies, which are antibodies or immunoglobulins that attack the body itself. Autoimmune diseases may be systemic and affect many parts of the body, or they may affect only specific organs or regions.

3 Glomerular Diseases Systemic lupus erythematosus (SLE) IgA nephropathy is a form of glomerular affects many parts of the body: primarily disease that results when immunoglobulin the skin and joints, but also the kidneys. A (IgA) forms deposits in the glomeruli, Because women are more likely to develop where it creates inflammation. IgA SLE than men, some researchers believe nephropathy was not recognized as a cause that a sex-linked genetic factor may play of glomerular disease until the late 1960s, a part in making a person susceptible, when sophisticated biopsy techniques were although viral infection has also been developed that could identify IgA deposits ­implicated as a triggering factor. Lupus in kidney tissue. is the name given to the kidney disease caused by SLE, and it occurs when The most common symptom of IgA autoantibodies form or are deposited nephropathy is blood in the urine, but in the glomeruli, causing inflammation. it is often a silent disease that may go ­Ultimately, the inflammation may create ­undetected for many years. The silent that keep the kidneys from functioning nature of the disease makes it difficult to properly. Conventional treatment for determine how many people are in the includes a combination of ­early stages of IgA nephropathy, when two , , a cytotoxic ­specific medical tests are the only way agent that suppresses the immune system, to detect it. This disease is estimated to and prednisolone, a be the most common cause of primary used to reduce inflammation. A newer glomerulonephritis—that is, glomerular immunosuppressant, mychophenolate disease not caused by a systemic disease mofetil (MMF), has been used instead of like lupus or diabetes mellitus. It appears cyclophosphamide. Preliminary studies to affect men more than women. Although indicate that MMF may be as effective IgA nephropathy is found in all age groups, as cyclophosphamide and has milder side young people rarely display signs of kidney effects. failure because the disease usually takes several years to progress to the stage where Goodpasture’s syndrome involves an it causes detectable complications. autoantibody that specifically targets the kidneys and the lungs. Often, the No treatment is recommended for early first indication that patients have the or mild cases of IgA nephropathy when autoantibody is when they cough up the patient has normal and blood. But lung damage in Goodpasture’s less than 1 gram of protein in a 24-hour syndrome is usually superficial compared urine output. When proteinuria exceeds 1 with progressive and permanent damage gram/day, treatment is aimed at protecting to the kidneys. Goodpasture’s syndrome is kidney function by reducing proteinuria a rare condition that affects mostly young and controlling blood pressure. Blood men but also occurs in women, children, pressure medicines—angiotensin- and older adults. Treatments include converting enzyme inhibitors (ACE immunosuppressive drugs and a blood- inhibitors) or angiotensin receptor blockers cleaning called plasmapheresis that (ARBs)—that block a called removes the autoantibodies. angiotensin are most effective at achieving those two goals simultaneously.

4 Glomerular Diseases Hereditary Nephritis— urine and elevated levels of creatinine and urea nitrogen in the blood, thus indicating reduced kidney function. High blood The primary indicator of Alport syndrome pressure frequently accompanies reduced is a family history of chronic glomerular ­kidney function in this disease. disease, although it may also involve hearing or vision impairment. This PSGN is most common in children syndrome affects both men and women, between the ages of 3 and 7, although it but men are more likely to experience can strike at any age, and it most often and sensory loss. affects boys. It lasts only a brief time and Men with Alport syndrome usually first usually allows the kidneys to recover. In show evidence of renal insufficiency a few cases, however, kidney damage while in their twenties and reach total may be permanent, requiring or kidney failure by age 40. Women rarely transplantation to replace renal function. have significant renal impairment, and hearing loss may be so slight that it can be Bacterial , infection of the detected only through testing with special ­tissues inside the heart, is also associated equipment. Usually men can pass the with subsequent glomerular disease. disease only to their daughters. Women Researchers are not sure whether the can transmit the disease to either their renal lesions that form after a heart sons or their daughters. Treatment focuses infection are caused entirely by the immune on controlling blood pressure to maintain response or whether some other disease kidney function. mechanism contributes to kidney damage. Treating the heart infection is the most Infection-related Glomerular effective way of minimizing kidney damage. Disease Endocarditis sometimes produces chronic kidney disease (CKD). Glomerular disease sometimes develops rapidly after an infection in other parts HIV, the virus that leads to AIDS, can of the body. post-streptococcal also cause glomerular disease. Between glomerulonephritis (PSGN) can occur 5 and 10 percent of people with HIV after an episode of strep throat or, in experience kidney failure, even before rare cases, impetigo (a skin infection). developing full-blown AIDS. HIV- The Streptococcus bacteria do not attack associated nephropathy usually begins the kidney directly, but an infection with heavy proteinuria and progresses may stimulate the immune system to rapidly (within a year of detection) to total overproduce antibodies, which are kidney failure. Researchers are looking circulated in the blood and finally deposited for that can slow down or reverse in the glomeruli, causing damage. PSGN this rapid deterioration of renal function, can bring on sudden symptoms of swelling but some possible solutions involving (edema), reduced urine output (), immunosuppression are risky because of and blood in the urine (hematuria). Tests the patients’ already compromised immune will show large amounts of protein in the system.

5 Glomerular Diseases Sclerotic Diseases to one part of the glomerulus and to a Glomerulosclerosis is scarring (sclerosis) minority of glomeruli in the affected of the glomeruli. In several sclerotic region. FSGS may result from a ­conditions, a systemic disease like lupus or systemic disorder or it may develop as an diabetes is responsible. Glomerulosclerosis idiopathic kidney disease, without a known is caused by the activation of glomerular cause. Proteinuria is the most common cells to produce material. This may symptom of FSGS, but, since proteinuria be stimulated by molecules called growth is associated with several other kidney factors, which may be made by glomerular conditions, the doctor cannot diagnose cells themselves or may be brought to the FSGS on the basis of proteinuria alone. glomerulus by the circulating blood that Biopsy may confirm the presence of enters the glomerular filter. glomerular scarring if the tissue is taken from the affected section of the kidney. Diabetic nephropathy is the leading cause But finding the affected section is a matter of glomerular disease and of total kidney of chance, especially early in the disease failure in the United States. Kidney disease process, when lesions may be scattered. is one of several problems caused by elevated levels of blood , the central Confirming a diagnosis of FSGS may feature of diabetes. In addition to scarring require repeat kidney biopsies. Arriving the kidney, elevated glucose levels appear at a diagnosis of idiopathic FSGS requires to increase the speed of blood flow into the identification of focal scarring and the the kidney, putting a strain on the filtering elimination of possible systemic causes glomeruli and raising blood pressure. such as diabetes or an immune response to infection. Since idiopathic FSGS is, by Diabetic nephropathy usually takes many definition, of unknown cause, it is difficult years to develop. People with diabetes to treat. No universal remedy has been can slow down damage to their kidneys by found, and most patients with FSGS controlling their blood glucose through progress to total kidney failure over 5 to healthy eating with moderate protein 20 years. Some patients with an aggressive intake, physical activity, and medications. form of FSGS reach total kidney failure People with diabetes should also be careful in 2 to 3 years. Treatments involving to keep their blood pressure at a level or other immunosuppressive drugs below 140/90 mm Hg, if possible. Blood appear to help some patients by decreasing pressure medications called ACE inhibitors proteinuria and improving kidney function. and ARBs are particularly effective at But these treatments are beneficial to only ­minimizing kidney damage and are now a minority of those in whom they are tried, frequently prescribed to control blood and some patients experience even poorer ­pressure in patients with diabetes and in kidney function as a result. ACE inhibitors patients with many forms of kidney disease. and ARBs may also be used in FSGS to decrease proteinuria. Treatment should Focal segmental glomerulosclerosis focus on controlling blood pressure and (FSGS) describes scarring in scattered blood levels, factors that may regions of the kidney, typically limited contribute to kidney scarring.

6 Glomerular Diseases Other Glomerular Diseases is frequently required. Some patients Membranous nephropathy, also called benefit from steroids, but this treatment membranous , is the second does not work for everyone. Additional most common cause of the nephrotic immunosuppressive medications are ­syndrome (proteinuria, edema, high helpful for some patients with progressive ­cholesterol) in U.S. adults after diabetic disease. nephropathy. Diagnosis of membranous (MCD) is the nephropathy requires a kidney biopsy, ­diagnosis given when a patient has the which reveals unusual deposits of and the kidney biopsy immunoglobulin G and complement C3, reveals little or no change to the structure substances created by the body’s immune of glomeruli or surrounding tissues when system. Fully 75 percent of cases are examined by a light microscope. Tiny drops idiopathic, which means that the cause of of a fatty substance called a lipid may be the disease is unknown. The remaining present, but no scarring has taken place 25 percent of cases are the result of other within the kidney. MCD may occur at any diseases like systemic lupus erythematosus, age, but it is most common in childhood. A B or C infection, or some forms small percentage of patients with idiopathic of . Drug therapies involving nephrotic syndrome do not respond to , gold, or have therapy. For these patients, the also been associated with membranous doctor may recommend a low- nephropathy. About 20 to 40 percent of and prescribe a to control edema. patients with membranous nephropathy The doctor may recommend the use of progress, usually over decades, to total nonsteroidal anti-inflammatory drugs kidney failure, but most patients experience to reduce proteinuria. ACE inhibitors either complete remission or continued and ARBs have also been used to reduce symptoms without progressive kidney proteinuria in patients with steroid-resistant failure. Doctors disagree about how MCD. These patients may respond to aggressively to treat this condition, since ­larger doses of steroids, more prolonged about 20 percent of patients recover use of steroids, or steroids in combination without treatment. ACE inhibitors with immunosuppressant drugs, such and ARBs are generally used to reduce as , cyclophosphamide, or proteinuria. Additional medication to cyclosporine. ­control high blood pressure and edema

7 Glomerular Diseases What are renal failure and Chronic Kidney Disease end-stage renal disease? Most forms of glomerular disease develop Renal failure is any acute or chronic loss gradually, often causing no symptoms for of kidney function and is the term used many years. CKD is the slow, gradual loss when some kidney function remains. Total of kidney function. Some forms of CKD kidney failure, sometimes called end-stage can be controlled or slowed down. For renal disease (ESRD), indicates permanent example, diabetic nephropathy can be loss of kidney function. Depending on the delayed by tightly controlling blood glucose form of glomerular disease, renal function levels and using ACE inhibitors and ARBs may be lost in a matter of days or weeks or to reduce proteinuria and control blood may deteriorate slowly and gradually over pressure. But CKD cannot be cured. the course of decades. Partial loss of renal function means that some portion of the patient’s nephrons Acute Renal Failure have been scarred, and scarred nephrons cannot be repaired. In many cases, CKD A few forms of glomerular disease cause leads to total kidney failure. very rapid deterioration of kidney function. For example, PSGN can cause severe Total Kidney Failure ­symptoms (hematuria, proteinuria, edema) within 2 to 3 weeks after a sore throat or To stay alive, a patient with total kidney skin infection develops. The patient may failure must go on dialysis— temporarily require dialysis to replace or —or receive a new renal function. This rapid loss of kidney kidney through transplantation. Patients function is called acute renal failure (ARF). with CKD who are approaching total Although ARF can be life-threatening kidney failure should learn as much about while it lasts, kidney function usually their treatment options as possible so they returns after the cause of the kidney failure can make an informed decision when the has been treated. In many patients, ARF is time comes. With the help of dialysis or not associated with any permanent damage. transplantation, many people continue to However, some patients may recover from lead full, productive lives after reaching ARF and subsequently develop CKD. total kidney failure.

8 Glomerular Diseases Points to Remember • The kidneys filter waste and extra fluid The Nephrotic Syndrome from the blood. • The nephrotic syndrome is a condition marked by very high levels • The filtering process takes place in the of protein in the urine; low levels nephron, where microscopic blood vessel of protein in the blood; swelling, filters, called glomeruli, are attached to especially around the eyes, feet, and fluid-collecting tubules. hands; and high cholesterol. • A number of different disease • The nephrotic syndrome is a set of ­processes can damage the symptoms, not a disease in itself. glomeruli and thereby cause kidney It can occur with many diseases, so failure. Glomerulonephritis and prevention relies on controlling the glomerulosclerosis are broad terms diseases that cause it. that include many forms of ­damage to the glomeruli. • Treatment of the nephrotic syndrome focuses on identifying and treating • Some forms of kidney failure can be the underlying cause, if possible, slowed down, but scarred glomeruli and reducing high cholesterol, blood can never be repaired. pressure, and protein in the urine • Treatment for the early stages of kidney through diet, medication, or both. failure depends on the disease causing • The nephrotic syndrome may go the damage. away once the underlying cause, • Early signs of kidney failure include if known, is treated. However, often blood or protein in the urine and a kidney disease is the underlying swelling in the hands, feet, abdomen, cause and cannot be cured. In these or face. Kidney failure may be silent cases, the kidneys may gradually for many years. lose their ability to filter wastes and excess water from the blood. If kidney failure occurs, the patient will need to be on dialysis or have a kidney transplant.

9 Glomerular Diseases Definitions sclerotic (skleh-ROT-ik) disease: A disease in which tissues become Signs and Symptoms of hardened or scarred. Glomerulonephritis systemic (sis-TEM-ik) disease: A disease edema (eh-DEE-muh): Swelling caused by that affects multiple parts of the the accumulation of fluid in cells and body, often as a result of substances tissues. In kidney failure, fluid may circulating in the blood. ­collect in the feet, hands, abdomen, or face. Treatments and Procedures hematuria (HEE-muh-TOOR-ee-uh): biopsy (BY-op-see): A procedure in which Blood in the urine. Blood may turn the a needle is used to obtain small pieces urine pink or cola-colored. of tissue from an organ for examination under different types of microscopes, hypoproteinemia (HY-po-PRO-teen-EE- each of which shows a different aspect mee-uh): Reduced levels of protein in of the tissue. the blood. dialysis (dy-AL-ih-sis): A medical proteinuria (PRO-tee-NOOR-ee-uh): treatment that removes wastes and Large amounts of protein in the urine. extra ­fluid from the blood after the (yoo-REE-mee-uh): Accumulation kidneys have stopped working. of urea and other wastes in the blood. immunosuppressant (im-YOON-oh-suh- These wastes, which become toxic in PRESS-unt): A medicine given to large amounts, are normally eliminated block the body’s immune system. through . plasmapheresis (PLAZ-muh-fer-EE-sis): Diseases and Conditions A medical treatment in which the blood autoimmune (AW-toh-ih-MYOON) is treated outside the body to remove disease: A disease in which the body’s harmful antibodies, and then returned own disease-fighting cells attack the to the patient. body itself. Kidney Parts and Organic (HY-per-TEN-shun): High Substances blood pressure, a condition that can (AN-tee-BOD-ee): A molecule cause kidney damage or be caused by that protects the body against disease kidney ­disease. by attacking foreign tissues or idiopathic (id-ee-o-PATH-ik) disease: A organisms. Antibodies are also called disease that occurs without a known immunoglobulins. cause. (AN-tih-jen): A substance that nephrotoxic (NEF-ro-TOKS-ik): Damaging triggers a response from the body’s to the kidneys. immune system.

10 Glomerular Diseases autoantibody (AW-toh-AN-tee-bod-ee): An For More Information antibody that attacks the body itself. American Association of Kidney Patients creatinine (kree-AT-ih-nin): A waste 2701 North Rocky Point Drive, Suite 150 product in the blood that results from Tampa, FL 33607 the normal breakdown of muscle. Phone: 1–800–749–2257 or 813–636–8100 Healthy kidneys filter creatinine from Fax: 813–636–8122 the blood. Email: [email protected] Internet: www.aakp.org glomerulus (gloh-MEHR-yoo-lus): The American Kidney Fund tiny cluster of looping blood vessels in 11921 Rockville Pike, Suite 300 the nephron, where wastes are filtered Rockville, MD 20852 from the blood. Phone: 1–800–638–8299 lipid (LIP-id): One of several fatty Internet: www.kidneyfund.org substances used in cells. Excess lipids Medical Education Institute, Inc. in the blood may result in harmful 414 D’Onofrio Drive, Suite 200 deposits in blood vessels. Madison, WI 53719 nephron (NEF-rahn): One of a million Phone: 1–800–468–7777 or 608–833–8033 tiny filtering units in each kidney. Fax: 608–833–8366 Each nephron is made up of both a Internet: www.meiresearch.org glomerulus and a fluid-collecting tubule www.lifeoptions.org that processes extra water and wastes. www.kidneyschool.org www.homedialysis.org protein (PRO-teen): A substance found National Kidney Foundation in food and used by the body to grow, repair tissue, and fight disease. 30 East 33rd Street New York, NY 10016–5337 urea (yoo-REE-uh): A waste material Phone: 1–800–622–9010 or 212–889–2210 found in blood after protein has been Fax: 212–689–9261 broken down. Healthy kidneys remove Internet: www.kidney.org urea from the blood. Damaged kidneys The NephCure Foundation may allow urea to accumulate in the blood, thus causing uremia. 15 Waterloo Avenue Berwyn, PA 19312 Phone: 1–866–NephCure (1–866–637–4287) Email: [email protected] Internet: www.nephcure.org

11 Glomerular Diseases National Kidney and Urologic Diseases Information Clearinghouse 3 Information Way Bethesda, MD 20892–3580 Phone: 1–800–891–5390 Fax: 703–738–4929 Email: [email protected] Internet: www.kidney.niddk.nih.gov The National Kidney and Urologic Diseases Information ­Clearinghouse (NKUDIC) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The NIDDK is part of the National Institutes of Health under the U.S. Department of Health and Human Services. Established in 1987, the Clearinghouse provides information about diseases of the kidneys and urologic ­system to ­people with kidney and urologic ­disorders and to their families, health care professionals, and the public. The NKUDIC answers inquiries, develops and distributes publications, and works closely with professional and patient organi­zations and Government agencies to coordinate resources about kidney and urologic diseases. Publications produced by the Clearinghouse are carefully reviewed by both NIDDK, scientists and outside experts.

This publication is not copyrighted. The Clearinghouse encourages users of this publication to duplicate and distribute as many copies as desired. This publication is available at www.kidney.niddk.nih.gov.

NIH Publication No. 14–4358 February 2014

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