Glomerulonephritis can be caused by various disorders, such as infections, an inherited genetic disorder, or autoimmune disorders.
Diagnosis is based on tests of blood and urine and sometimes imaging tests, a biopsy of the kidneys, or both.
People often need to restrict salt and protein intake and take diuretics or antibiotics until kidney function improves.
(See also Overview of Kidney Filtering Disorders Overview of Kidney Filtering Disorders Each kidney contains about 1 million filtering units (glomeruli). The glomeruli are made up of many microscopic clusters of tiny blood vessels (capillaries) with small pores. These blood vessels... read more .)
Glomerulonephritis can be
Acute: Develops over a short time
Chronic: Develops and progresses slowly
In 1% of children and 10% of adults who have acute glomerulonephritis, it evolves into rapidly progressive glomerulonephritis, in which most of the glomeruli are destroyed, resulting in kidney failure Overview of Kidney Failure This chapter includes a new section on COVID-19 and acute kidney injury (AKI). Kidney failure is the inability of the kidneys to adequately filter metabolic waste products from the blood. Kidney... read more .
Glomerulonephritis can be
Primary, originating in the kidneys
Secondary, caused by a vast array of disorders
The disorders that cause secondary glomerulonephritis may affect parts of the body other than the kidneys.
Acute glomerulonephritis most often occurs as a complication of a throat or skin infection with streptococcus (for example, strep throat), a type of bacteria. Acute glomerulonephritis that occurs after a streptococcal infection Streptococcal Infections Streptococcal infections are caused by any one of several species of Streptococcus. These gram-positive, sphere-shaped (coccal) bacteria (see figure How Bacteria Shape Up) cause many... read more (poststreptococcal glomerulonephritis) typically develops in children between the ages of 2 and 10 after recovery from the infection. Infections with other types of bacteria, such as staphylococcus and pneumococcus, viral infections, such as chickenpox Chickenpox Chickenpox is a highly contagious viral infection with the varicella-zoster virus that causes a characteristic itchy rash, consisting of small, raised, blistered, or crusted spots. Chickenpox... read more , and parasitic infections, such as malaria Malaria Malaria is infection of red blood cells with one of five species of Plasmodium, a protozoan. Malaria causes fever, chills, sweating, a general feeling of illness (malaise), and sometimes... read more , can also result in acute glomerulonephritis. Acute glomerulonephritis that results from any of these infections is called postinfectious glomerulonephritis.
Acute glomerulonephritis may also be caused by noninfectious disorders, including membranoproliferative glomerulonephritis, immunoglobulin A (IgA) nephropathy, immunoglobulin A–associated vasculitis Immunoglobulin A–Associated Vasculitis Immunoglobulin A–associated vasculitis (formerly called Henoch-Schönlein purpura) is inflammation of mainly small blood vessels that most often occurs in children. A rash of reddish purple bumps... read more , systemic lupus erythematosus Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus is a chronic autoimmune inflammatory connective tissue disorder that can involve joints, kidneys, skin, mucous membranes, and blood vessel walls. Problems in the... read more (lupus), cryoglobulinemia Cryoglobulinemia Conditions that cause an abnormal protein or an abnormal amount of certain normal proteins in the blood can cause blood vessels to become fragile. When these fragile blood vessels break, people... read more , Goodpasture syndrome Goodpasture Syndrome Goodpasture syndrome is an uncommon autoimmune disorder in which bleeding into the lungs and progressive kidney failure occur. People usually have difficulty breathing and may cough up blood... read more , and granulomatosis with polyangiitis Granulomatosis with Polyangiitis Granulomatosis with polyangiitis often begins with inflammation of small- and medium-sized blood vessels and tissues in the nose, sinuses, throat, lungs, or kidneys. The cause is unknown. The... read more . Acute glomerulonephritis that develops into rapidly progressive glomerulonephritis most often results from conditions that involve an abnormal immune reaction.
Often, chronic glomerulonephritis seems to result from some of the same conditions that cause acute glomerulonephritis, such as IgA nephropathy or membranoproliferative glomerulonephritis. Sometimes, acute glomerulonephritis does not resolve and instead becomes long lasting (chronic). Occasionally, chronic glomerulonephritis is caused by hereditary nephritis Alport Syndrome Alport syndrome is a hereditary (genetic) disorder that results in glomerulonephritis in which kidney function is poor, blood is present in the urine, and deafness and eye abnormalities sometimes... read more , an inherited genetic disorder. In many people with chronic glomerulonephritis, the cause cannot be identified.
About half of the people with acute glomerulonephritis have no symptoms. If symptoms do occur, the first to appear are tissue swelling (edema) due to fluid retention, low urine volume, and production of urine that is dark because it contains blood. Edema may first appear as puffiness of the face and eyelids but later is prominent in the legs. Blood pressure increases (see The Body's Control of Blood Pressure The Body's Control of Blood Pressure High blood pressure (hypertension) is persistently high pressure in the arteries. Often no cause for high blood pressure can be identified, but sometimes it occurs as a result of an underlying... read more ) as kidney function becomes impaired. Some people become drowsy or confused. In older people, nonspecific symptoms, such as nausea and a general feeling of illness (malaise), are more common.
When rapidly progressive glomerulonephritis develops, weakness, fatigue, and fever are the most frequent early symptoms. Loss of appetite, nausea, vomiting, abdominal pain, and joint pain are also common. About 50% of people have a flu-like illness in the month before kidney failure develops. These people have edema and usually produce very little urine. High blood pressure is uncommon and rarely severe when it does occur.
Because chronic glomerulonephritis usually causes only very mild or subtle symptoms, it goes undetected for a long time in most people. Edema may occur. High blood pressure High Blood Pressure High blood pressure (hypertension) is persistently high pressure in the arteries. Often no cause for high blood pressure can be identified, but sometimes it occurs as a result of an underlying... read more is common. The disease may progress to kidney failure, which can cause itchiness, decreased appetite, nausea, vomiting, fatigue, and difficulty breathing.
Doctors investigate the possibility of acute glomerulonephritis in people who develop symptoms that suggest the disorder. They also investigate the possibility in people whose laboratory test results (which may be done to evaluate nonspecific symptoms or as part of a routine medical evaluation) indicate kidney dysfunction or blood in the urine. Laboratory tests show variable amounts of protein and blood cells in the urine and often kidney dysfunction, as shown by a high concentration of urea and creatinine (waste products) in the blood.
In people with rapidly progressive glomerulonephritis, casts (clumps of red blood cells or white blood cells) are often visible in a urine sample that is examined under a microscope. Blood tests usually detect anemia Overview of Anemia Anemia is a condition in which the number of red blood cells is low. Red blood cells contain hemoglobin, a protein that enables them to carry oxygen from the lungs and deliver it to all parts... read more .
When doctors suspect glomerulonephritis, a biopsy of a kidney Tissue and Cell Sampling Site-specific biopsies and cell sampling are also used in the evaluation of people with suspected kidney and urinary tract disorders. (See also Overview of the Urinary Tract.) A kidney biopsy... read more is usually done to confirm the diagnosis, help determine the cause, and determine the amount of scarring and potential for reversibility. Kidney biopsy is done by inserting a needle in one of the kidneys under ultrasound or computed tomography (CT) guidance to obtain a small amount of kidney tissue. Although kidney biopsy is an invasive procedure and occasionally can cause complications, it is usually safe.
Chronic glomerulonephritis develops gradually, and therefore, a doctor may not be able to tell exactly when it began. It may be discovered when a urine test, done as part of a medical examination, reveals the presence of protein and blood cells in the urine in a person who is feeling well, has normal kidney function, and has no symptoms. Doctors usually do an imaging test of the kidneys, such as ultrasonography or CT.
A kidney biopsy is the most reliable way to distinguish chronic glomerulonephritis from other kidney disorders. A biopsy, however, is rarely done in advanced stages. In these cases, the kidneys are shrunken and scarred, and the chance of obtaining specific information about the cause is small. Doctors suspect that the kidneys are shrunken and scarred if kidney function has been poor for a long time and the kidneys appear abnormally small on an imaging test.
Determining the cause of glomerulonephritis
Additional tests are sometimes helpful for identifying the cause. For example, in the diagnosis of postinfectious glomerulonephritis, a throat culture may provide evidence of streptococcal infection. Blood levels of antibodies against streptococci may be higher than normal or progressively increase over several weeks. Acute glomerulonephritis that follows an infection other than strep throat is usually easier to diagnose because its symptoms often begin while the infection is still obvious. Cultures and blood tests that help identify the organisms that cause these other types of infections are sometimes needed to confirm the diagnosis.
When doctors suspect an autoimmune cause for glomerulonephritis, they do blood tests for antibodies directed against some of the body's own tissues (called autoantibodies) and tests that assess the complement system, a system of proteins involved in the body's immune system.
Acute poststreptococcal glomerulonephritis resolves completely in most cases, especially in children. About 1% of children and 10% of adults develop chronic kidney disease Chronic Kidney Disease Chronic kidney disease is a slowly progressive (months to years) decline in the kidneys’ ability to filter metabolic waste products from the blood. Major causes are diabetes and high blood pressure... read more .
The prognosis for people with rapidly progressive glomerulonephritis depends on the severity of glomerular scarring and whether the underlying disease, such as infection, can be cured. In some people who are treated early (within days to weeks), kidney function is preserved and dialysis is not needed. However, because the early symptoms can be subtle and vague, most people who have rapidly progressive glomerulonephritis are not aware of the underlying disease and do not seek medical care until kidney failure develops.
If treatment occurs late, the person is more likely to develop chronic kidney disease Chronic Kidney Disease Chronic kidney disease is a slowly progressive (months to years) decline in the kidneys’ ability to filter metabolic waste products from the blood. Major causes are diabetes and high blood pressure... read more with kidney failure. Because kidney failure tends to develop before people notice it, 80 to 90% of people who have rapidly progressive glomerulonephritis become dependent upon dialysis Dialysis Dialysis is an artificial process for removing waste products and excess fluids from the body, a process that is needed when the kidneys are not functioning properly. There are a number of reasons... read more . The prognosis also depends on the cause, the person's age, and any other diseases the person might have. When the cause is unknown or the person is older, the prognosis is worse.
In some children and adults who do not recover completely from acute glomerulonephritis, other types of kidney disorders develop, such as asymptomatic proteinuria and hematuria syndrome Asymptomatic Proteinuria and Hematuria Syndrome Asymptomatic proteinuria and hematuria syndrome is the result of diseases of glomeruli (clusters of microscopic blood vessels in the kidneys that have small pores through which blood is filtered)... read more or nephrotic syndrome Nephrotic Syndrome Nephrotic syndrome is a disorder of the glomeruli (clusters of microscopic blood vessels in the kidneys that have small pores through which blood is filtered) in which excessive amounts of protein... read more . Other people with acute glomerulonephritis, especially older adults, often develop chronic glomerulonephritis.
Treating the causative disorder
For rapidly progressive glomerulonephritis, suppression of the immune system
For chronic glomerulonephritis, an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin II receptor blocker (ARB) and reducing dietary sodium
No specific treatment is available in most cases of acute glomerulonephritis. The disorder causing glomerulonephritis is treated when possible. Following a diet that is low in protein and sodium may be necessary until kidney function recovers. Diuretics may be prescribed to help the kidneys excrete excess sodium and water. High blood pressure needs to be treated.
When a bacterial infection is suspected as the cause of acute glomerulonephritis, antibiotics are usually ineffective because the nephritis begins 1 to 6 weeks (average, 2 weeks) after the infection, which has, by then, usually resolved. However, if a bacterial infection is still present when acute glomerulonephritis is discovered, antibiotic therapy is started. Antimalarial drugs may be beneficial if glomerulonephritis is caused by malaria.
Some autoimmune disorders that cause glomerulonephritis are treated with corticosteroids, drugs that suppress the immune system, or both.
Rapidly progressive glomerulonephritis
For rapidly progressive glomerulonephritis, drugs to suppress the immune system are started promptly. High doses of corticosteroids are usually given intravenously for about a week, followed by a variable period of time when they are taken by mouth. Cyclophosphamide, an immunosuppressant, may also be given. In addition, plasma exchange is sometimes used to remove antibodies from the blood. The sooner treatment occurs, the less likely are kidney failure and the need for dialysis. Kidney transplantation Kidney Transplantation Kidney transplantation is the removal of a healthy kidney from a living or recently deceased person and then its transfer into a person with end-stage kidney failure. (See also Overview of Transplantation... read more is sometimes considered for people who develop chronic kidney disease with kidney failure, but rapidly progressive glomerulonephritis may recur in the transplanted kidney.
Taking either an ACE inhibitor or an ARB often slows progression of chronic glomerulonephritis and tends to reduce blood pressure and the excretion of protein in the urine. Reducing blood pressure and sodium intake are considered beneficial. Restricting the amount of protein in the diet is modestly helpful in reducing the rate of kidney deterioration. End-stage kidney failure can be treated with dialysis Dialysis Dialysis is an artificial process for removing waste products and excess fluids from the body, a process that is needed when the kidneys are not functioning properly. There are a number of reasons... read more or a kidney transplant Kidney Transplantation Kidney transplantation is the removal of a healthy kidney from a living or recently deceased person and then its transfer into a person with end-stage kidney failure. (See also Overview of Transplantation... read more .
The following are some English-language resources that may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
American Kidney Fund, Glomerulonephritis: General information on glomerulonephritis, including answers to frequently asked questions
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Glomerular Diseases: General information on glomerular diseases, including the roles of glomeruli in normal kidney function, chronic kidney disease, and nephrotic syndrome