Glomerulonephritis means the glomeruli, the tiny filters in your kidneys that clean your blood, are inflamed. It can start suddenly or develop slowly over years, and it often causes no symptoms until a urine or blood test picks it up. Some forms clear up once the cause is treated, while others need long-term care to protect your kidneys.
Key Takeaways
- Glomerulonephritis is inflammation of the kidneys’ filters, which can let blood and protein leak into your urine.
- It can be acute (sudden), chronic (slow, over years) or rapidly progressive, with kidney function lost over days to weeks.
- Causes include IgA nephropathy, lupus, infections such as strep throat and ANCA vasculitis, though sometimes no cause is found.
- Urine and blood tests raise the question, and a kidney biopsy is often needed to confirm the type.
- Treatment depends on the cause and may include blood pressure medicines, medicines that calm the immune system and eating less salt.
What Do the Glomeruli Do, and What Happens When They Are Inflamed?
Glomeruli are tiny filtering units made of very small blood vessels. They work like a kitchen strainer: as blood moves through, waste and extra water pass out to become urine, while protein and blood cells stay in your blood.
In glomerulonephritis, the filters become inflamed and can scar. Damaged filters may leak blood and protein into your urine and may not remove waste and extra fluid as well as they should. It is one of two main groups of glomerular disease. The other, glomerulosclerosis, is scarring from hardened blood vessels. Our guide to different types of kidney disease shows where it fits.
What Is the Difference Between Acute and Chronic Glomerulonephritis?
Acute glomerulonephritis starts suddenly and can get better when the cause is treated, so early treatment matters. Chronic glomerulonephritis develops quietly over years and can lead to kidney failure, though treatment can help keep it from getting worse. Rapidly progressive glomerulonephritis causes loss of kidney function over days to weeks. One form can turn into another: some people have an acute attack and a chronic condition years later.
Doctors also describe the pattern they see. A nephritic pattern means red blood cells from damaged filters show up in the urine, sometimes with high blood pressure, less urine and a rise in creatinine, a waste product in the blood. Nephrotic syndrome is different: large amounts of protein leak into the urine, causing low protein in the blood, swelling and high cholesterol. Some diseases, including lupus nephritis, can show features of both.
What Causes Glomerulonephritis?
Many cases happen when the immune system, which normally fights germs, damages the glomeruli. Common types include:
- IgA nephropathy: clumps of an antibody called immunoglobulin A build up in the glomeruli and cause inflammation. About 1 in 10 kidney biopsies in the U.S. show it, and signs sometimes first appear after a cold or sore throat.
- Lupus nephritis: kidney inflammation caused by lupus, an autoimmune disease. As many as 5 in 10 adults with lupus will have kidney disease.
- Post-infectious glomerulonephritis: the immune system attacks the kidneys while fighting an infection, most often strep. It mainly affects children, usually 1 to 2 weeks after strep throat or a few weeks after a strep skin infection.
- ANCA vasculitis: rare autoimmune diseases that inflame small blood vessels in the kidneys, lungs, sinuses and other organs.
Other causes include anti-GBM (Goodpasture) disease, which can also affect the lungs, infections such as hepatitis C, some medicines, and rare inherited conditions such as Alport syndrome. Sometimes no cause is found.
What Are the Signs of Glomerulonephritis?
Many people have no warning signs, and the disease is often found during tests for something else. When signs appear, they can include:
- pink, red, brown or cola-colored urine from blood (often the blood is only seen under a microscope)
- foamy or bubbly urine from protein
- swelling in your face, around your eyes, or in your ankles and legs
- high blood pressure
- making less urine than usual
- feeling more tired than usual or having trouble concentrating
Some causes bring other symptoms, such as joint pain, fever and a rash with lupus, or a stuffy or bloody nose with ANCA vasculitis. Dark urine can also come from some medicines and food coloring, so ask a clinician if you are not sure of the cause.
How Is Glomerulonephritis Diagnosed?
Urine tests check for blood and measure how much protein is leaking. Blood tests check creatinine and eGFR to show how well your kidneys filter, and antibody tests can point to causes such as lupus or ANCA vasculitis. An ultrasound or CT scan may show the size and shape of your kidneys. Read more about kidney function test results and protein in the urine.
A kidney biopsy is often needed to confirm glomerulonephritis, though it is rarely needed for typical post-infectious cases in children. A small piece of kidney tissue is removed with a needle and examined under special microscopes to show the type, how much damage there is and which treatment may help. Learn what happens during a kidney biopsy.
How Is Glomerulonephritis Treated?
Treatment depends on the type and cause, and the goal is to stop or slow further damage. Your care team may use:
- Blood pressure medicines, often an ACE inhibitor or ARB, which can also reduce protein in the urine.
- Diuretics (water pills) to remove extra fluid and ease swelling.
- Medicines that calm the immune system, such as corticosteroids like prednisone or other immunosuppressants, for types such as lupus nephritis and ANCA vasculitis. Plasma exchange, which filters harmful antibodies from the blood, is used in some severe cases.
- Treatment of the cause, such as antibiotics for an infection. Very mild post-infectious cases may need nothing more than eating less salt.
- Less salt, with meals planned alongside a registered dietitian.
Newer medicines are available for some types, including IgA nephropathy and lupus. Medicines that calm the immune system raise your risk of infection, so ask about vaccines. Never start, stop or change a medicine, including over-the-counter medicines and supplements, without talking to your doctor or pharmacist.
What Is the Outlook, and Why Does Follow-Up Matter?
The outlook depends on the type. Some mild cases go away without treatment. Most children with post-infectious glomerulonephritis recover fully, while adults are more likely to be left with some loss of kidney function. IgA nephropathy often does not get worse over time, but in some people it leads to kidney failure. Lupus nephritis often responds well to treatment, and early treatment matters in ANCA vasculitis because untreated disease can cause serious kidney damage.
Follow-up matters because glomerulonephritis can go away and come back, and an acute case can become chronic. After post-infectious glomerulonephritis, small amounts of blood may stay in the urine for months. Regular urine and blood tests show whether protein levels and eGFR are holding steady, often before you would notice any change.
When Should You Get Care?
Call 911 or go to the nearest emergency room if you have trouble breathing, chest pain, confusion, a seizure, or very little or no urine. Some forms of glomerulonephritis can cause kidney failure quickly, which needs treatment right away.
Make an appointment soon if you notice:
- pink, red, brown or cola-colored urine
- foamy urine that keeps happening
- new swelling in your face, around your eyes or in your legs
- making less urine than usual
- any of these after a recent strep throat or skin infection, or if you have lupus
Frequently Asked Questions
Is Glomerulonephritis the Same as a Kidney Infection?
No. It is inflammation of the kidneys’ filters, usually caused by the immune system. Even post-infectious glomerulonephritis comes from the immune system reacting to an infection elsewhere, such as strep throat.
Does Glomerulonephritis Always Lead to Kidney Failure?
No. It may go away once the cause is treated, or it may come and go. Less often, it does not respond to treatment and leads to kidney failure, which is treated with dialysis or a kidney transplant.
Can Glomerulonephritis Run in Families?
Some types can. Having a family member with glomerular disease raises your risk, and a few causes, such as Alport syndrome, are inherited.
Is There a Special Diet for Glomerulonephritis?
Food has not been shown to cause or prevent it. If you have it, you may be asked to limit salt and sometimes cholesterol or fluids, and a registered dietitian can help.
Do I Need a Referral to See a Nephrologist?
In most cases, you need a referral from your primary care doctor to see a nephrologist, but it may depend on your insurance plan.
Talk to ANC About Glomerulonephritis
Glomerulonephritis is one of the conditions ANC treats. If a urine test has shown blood or protein, or you have been told you have glomerulonephritis, Contact ANC or call 651-772-6251, Monday to Friday, 8:30 AM to 4 PM.
Sources
- National Kidney Foundation: Glomerulonephritis
- NIDDK: Glomerular Disease
- Cleveland Clinic: Glomerulonephritis (GN)
- NIDDK: IgA Nephropathy
- National Kidney Foundation: ANCA-Associated Vasculitis (AAV)
Medical Disclaimer
This article is for general educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your specific care and treatment options.
