Glomerulonephritis is damage to the tiny filters inside your kidneys (the glomeruli).
It is often caused by your immune system attacking healthy body tissue.
In most cases glomerulonephritis does not cause any noticeable symptoms and is often diagnosed when blood or urine tests are carried out for another reason.
Having blood in your urine does not mean that you definitely have glomerulonephritis, but you should see your doctor so the cause can be investigated.
Why does glomerulonephritis happen?
Commonly, glomerulonephritis is the result of a problem with the immune system, which causes it to attack healthy tissue in the kidneys. However, there are many cases where the exact cause is unknown.
Conditions that can cause problems with the immune system include vasculitis and a type of lupus called systemic lupus erythematosus.
Glomerulonephritis is sometimes short-lived (acute), but more often it lasts for a long time (chronic).
Read more about the causes of glomerulonephritis.
How is glomerulonephritis treated?
The recommended treatment will depend on the cause and severity of your condition. Mild cases may not need any treatment.
Treatment can be as simple as making changes to your diet, such as eating less salt to reduce the strain on your kidneys.
Medications to lower blood pressure, such as angiotensin converting enzyme (ACE) inhibitors, are commonly prescribed for glomerulonephritis because they help protect the kidneys.
If the condition is caused by a problem with your immune system, medications called immunosuppressants may be used.
In most cases glomerulonephritis does not cause any obvious symptoms.
There may be small amounts of blood or protein in your urine, but these are often not visible and may only become apparent after a sample of your urine has been tested.
In severe cases of glomerulonephritis, you may actually see blood in your urine. This is known as visible haematuria. Your urine may also be frothy if it contains a large amount of protein.
You should see your doctor if you notice blood in your urine. There are many conditions besides glomerulonephritis that can cause visible haematuria and your doctor can investigate the cause.
Many people with glomerulonephritis also have high blood pressure.
If a lot of protein leaks into your urine, the amount of protein in your blood can decrease. This is called nephrotic syndrome and it causes fluid to build up in your body (oedema), because the proteins in your blood normally help keep fluid in the blood vessels.
The build-up of fluid often develops in your legs and lower back, although it can also affect your abdomen, face, hands or lungs. In some cases, these areas may swell.
Depending on your type of glomerulonephritis, other parts of your body can also be affected and may result in symptoms such as:
- joint pain
- breathing problems
It is very rare to get kidney pain with glomerulonephritis. If you have pain on the left or right side of your back that feels like it comes from your kidneys, it is more likely to have another cause, such as:
- a kidney infection – this usually occurs when a bacterial infection spreads from your bladder into one of your kidneys
- kidney stones – stone-like lumps that can develop in one or both of your kidneys
As kidney pain can have several causes, it is important to see your doctor for the correct diagnosis.
Glomerulonephritis is often caused by a problem with your immune system, although it is not always clear why this happens.
Immune system problem
The job of your immune system is to recognise infections and use antibodies to get rid of them. However, in some cases of glomerulonephritis, the immune system mistakes some normal parts of the body for organisms that cause infections.
This can cause the immune system to attack healthy body tissue, including the tissue in the kidneys. It is not clear exactly what causes this problem with the immune system. Sometimes it is part of a condition such as systemic lupus erythematosus (SLE) or vasculitis.
The types of glomerulonephritis caused by problems with the immune system include:
- ANCA vasculitis – where antibodies cause damage to blood vessels in different parts of the body, including the kidneys
- IgA nephropathy (immunoglobulin A nephropathy), also known as Berger disease – where a build-up of an antibody called immunoglobulin A damages the kidneys
- membranous nephropathy – where the membranes of the glomeruli thicken
- lupus nephritis – where glomerulonephritis is part of systemic lupus erythematosus (SLE). Lupus nephritis can be diagnosed when SLE is first recognised or it can occur in someone already known to have lupus
- anti-glomerular basement membrane disease, also known as Goodpasture’s disease – a very rare condition where antibodies attack the membranes of the glomeruli
The terms crescentic glomerulonephritis and necrotizing glomerulonephritis are used to identify cases where inflammation is very severe. Crescentic and necrotizing glomerulonephritis can have various causes but often they are due to ANCA vasculitis, IgA nephropathy or lupus nephritis.
Although it is not certain, the immune system may also play a role in causing other types of glomerulonephritis, such as:
- minimal change disease – where the glomeruli are damaged but the damage can only be seen with a special high-power microscope (this type is more common in children but can also occur in adults)
- focal and segmental glomerulosclerosis – where there is inflammation and scarring of the glomeruli
Occasionally these conditions are due to faulty genes that directly affect cells in the glomeruli.
Complication of infections
In some cases, the immune system abnormalities are triggered by an infection, such as:
- HIV – a virus that attacks the body’s immune system
- hepatitis B and hepatitis C – viral infections of the liver
- endocarditis (infection of the heart valves)
Most people who develop glomerulonephritis do not have a family member with the condition. However, certain types of glomerulonephritis can run in families. For example, Alport syndrome – which causes damage to the blood vessels in the kidneys – can be inherited.
If you are diagnosed with a type of glomerulonephritis that runs in families, your doctor can advise you about the chances of someone else in your family being affected. They may recommend screening, which can identify people who may be at increased risk of developing the condition.
As the symptoms of glomerulonephritis are not always obvious, it is often only diagnosed after a routine medical check-up or tests for another condition.
In most cases, blood and urine tests offer a good indication of kidney problems.
A blood test can measure your creatinine level. Creatinine is a substance produced by your muscles and is present in your bloodstream. The kidneys usually remove creatinine from the blood.
If your kidneys are not working normally, the creatinine level in your blood will rise, which can be detected during a blood test.
The creatinine result is converted into a value called the 'estimated glomerular filtration rate' (eGFR) to determine kidney function.
Your urine can be tested in two ways:
- Your doctor or another healthcare professional can dip special strips into a sample of your urine. This is called the dipstick technique, and the strip changes colour if there is any blood or protein in your urine.
- A sample of your urine is sent to a laboratory to more accurately measure how much protein it contains or to look for blood cells.
The results of blood and urine tests may be combined to decide whether you need to see a specialist for further investigations.
Specialist blood tests
Several specialist blood tests may be carried out to look for causes of glomerulonephritis. These include:
- tests to look for systemic lupus erythematosus, such as an anti-nuclear antibody test – see diagnosing lupus for more information
- the anti-neutrophil cytoplasmic antibody (ANCA) blood test, used to diagnose vasculitis (inflammation of the blood vessels)
- tests to look for specific infections such as hepatitis B or hepatitis C
- the anti-glomerular basement membrane blood test, used to diagnose Goodpasture’s disease (when antibodies attack the membranes of the glomeruli)
If your kidney problem needs to be investigated further, you may need to have an ultrasound scan of your kidney.
An ultrasound scan uses high-frequency sound waves to create an image of your kidneys which will be looked at by a specialist. The specialist will be able to check the size of your kidneys, make sure there are no blockages and look for anything else that might explain why they are not working as they should.
If you need a kidney biopsy (see below), you will need a kidney ultrasound scan first.
If glomerulonephritis is suspected, a procedure to remove a small sample of kidney tissue may be recommended. This is called a biopsy.
A kidney biopsy is usually carried out using local anaesthetic to numb the area. An ultrasound machine will be used to locate your kidneys and a small needle will be used to take a sample. The test carries a small risk of bleeding so you will need to remain in hospital for a while on the day of the procedure, or sometimes overnight.
The tissue sample will then be examined under a microscope in a laboratory to confirm a diagnosis of glomerulonephritis, find out how serious the condition is, and determine the most appropriate course of treatment. Read more about treating glomerulonephritis.
Treatment for glomerulonephritis largely depends on the cause of your condition and the symptoms you have.
In mild cases, treatment is not always necessary. If treatment is needed it will usually be carried out by a kidney specialist (a nephrologist or renal medicine consultant).
Treatment for glomerulonephritis is usually effective, although complications of glomerulonephritis can sometimes develop.
Your doctor or dietitian will give you relevant advice about diet.
You may be advised to:
- reduce your intake of food that contains a high amount of salt
- reduce your intake of food or drinks that contain a high amount of potassium
- reduce your intake of fluid
These measures can help control your blood pressure and ensure the amount of fluid in your body is regulated.
You may also be advised about protein in your diet and eating a diet low in saturated fats to help lower your cholesterol.
You will be regularly reviewed to ensure your blood contains the right levels of potassium, sodium chloride and other salts.
Smoking may make kidney disease caused by glomerulonephritis worse more quickly. It also increases the risk of complications such as heart disease and stroke which are already more common in people with glomerulonephritis.
Therefore, if you have glomerulonephritis and you smoke, stopping smoking can offer important health benefits.
Severe cases of glomerulonephritis caused by problems with the immune system are sometimes treated with types of medicine known as immunosuppressants. These medicines reduce the activity of your immune system.
Suppressing your immune system can be an effective way of treating glomerulonephritis, but it also increases your risk of infections and can cause other side effects.
Therefore, treatment with immunosuppressant medicines will be adjusted to the level needed to treat your condition and will be carefully monitored.
Corticosteroids are medicines containing steroids, a type of hormone. Hormones are powerful chemicals that have a wide range of effects on the body.
Corticosteroids are used to reduce inflammation (swelling) and suppress your immune system. Prednisolone is a common corticosteroid you might be prescribed.
Once your kidneys have started to recover, your dose of corticosteroid medicine will usually be lowered. You may continue to take a small dose, or this treatment may be stopped altogether.
Cyclophosphamide is used in very high doses to treat some cancers, but it is also an established treatment, in much lower doses, for glomerulonephritis.
Other medicines to help control your immune system include mycophenolate mofetil, azathioprine, rituximab, ciclosporin and tacrolimus.
If your condition is thought to be linked to a viral infection, it may be treated with antiviral medication.
Sometimes, individual symptoms can be treated. For example, swelling caused by a build-up of fluid may be treated with a type of medication called a diuretic.
Treating high blood pressure
Glomerulonephritis often leads to high blood pressure, which can cause further kidney damage and other health problems.
Your blood pressure will be carefully monitored by the healthcare professionals treating you, and you may need to take medicines, such as angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARB), which lower blood pressure and help reduce the amount of protein that leaks into your urine.
Often, people who have high blood pressure and kidney disease need to take several medicines to control their blood pressure.
As these medications can help protect the kidneys, it is common to be prescribed these medications even if your blood pressure is not particularly high.
Read more about treating high blood pressure.
Treating high cholesterol
High cholesterol levels are common in people with glomerulonephritis.
Your doctor may recommend treatment with medication to reduce cholesterol and help protect you against complications such as heart and vascular disease. Statins are the most frequently used medication.
Read more about treating high cholesterol.
Plasma is a clear, yellowish fluid that is part of the blood. It contains proteins, such as the antibodies that can cause your kidneys to become inflamed. Plasma exchange is a procedure that involves removing some of the plasma from your blood.
During plasma exchange, you are connected to a machine that gradually removes some of your blood. The plasma is separated from the blood cells and removed. A plasma substitute is then added to the blood before it is put back into your body.
Plasma exchange may be used in certain circumstances if your condition is particularly severe (usually if you have a type of glomerulonephritis called ANCA vasculitis). Evidence suggests it may reduce the risk of end-stage kidney failure, where the kidneys have permanently failed.
Read more about how plasma products are used.
Treating chronic kidney disease or kidney failure
In severe cases that cannot be improved with other treatments, you may require:
Further problems can sometimes develop as a result of glomerulonephritis.
High blood pressure
High blood pressure (hypertension) is a common complication of glomerulonephritis. This is because your kidneys help regulate your blood pressure.
Many people with glomerulonephritis are prescribed medication to help lower their blood pressure. If this type of medication is recommended for you, it is important to take it as prescribed to protect your kidneys from further damage. It will also help reduce your risk of developing other conditions caused by high blood pressure.
If it is not treated properly, long-term high blood pressure increases your risk of developing:
- heart disease
- a stroke
- problems with the circulation to your legs, such as peripheral arterial disease (PAD)
- further worsening of your kidney function
High cholesterol is another complication of glomerulonephritis.
Many people with glomerulonephritis are prescribed medications to help lower their cholesterol. If this type of medication is recommended for you, it is important to take it as prescribed to reduce your risk of developing other conditions caused by high cholesterol.
Similarly to high blood pressure, high cholesterol can in the long term increase your risk of developing:
- heart disease
- a stroke
- problems with the circulation to your legs, such as peripheral arterial disease (PAD)
Blood clots (thrombosis)
People with glomerulonephritis can be at increased risk of developing blood clots (thrombosis](yourmd:/condition/thrombosis/introduction)), including [deep vein thrombosis (DVT) of the leg. Thrombosis can cause painful swelling in one leg or sometimes chest pain and breathing problems. Your doctor will advise you about medication that may help to protect you against thrombosis or treat thrombosis if it occurs.
Effects on other internal organs
Glomerulonephritis directly affects the kidneys, but other parts of your body may also be affected. This is most common in cases where glomerulonephritis is part of a condition such as vasculitis or lupus, or due to an infection.
If this is the case, the effects can range from a spotty red rash over your legs to painful swollen joints or adverse effects on your lungs and liver.
Discuss any symptoms you have with your doctor or kidney specialist to determine whether they could be related to glomerulonephritis.
Chronic kidney disease and kidney failure
Some people with glomerulonephritis are left with permanent damage to the kidneys and develop chronic kidney disease (CKD). CKD often leads to reduced kidney function, and in a small proportion of people, the kidneys fail completely.