Glomerulonephritis is damage to the tiny filters inside your kidneys (the glomeruli). It's often caused by your immune system attacking healthy body tissue.

Glomerulonephritis doesn't usually cause any noticeable symptoms. It's more likely to be diagnosed when blood or urine tests are carried out for another reason.

Although mild cases of glomerulonephritis can be treated effectively, for some people the condition can lead to long-term kidney problems.

This topic covers:

Symptoms

When to get medical advice

Causes

Treatment

Complications

Symptoms of glomerulonephritis

In severe cases of glomerulonephritis, you may see blood in your urine. However, this is usually noticed when a urine sample is tested.

Your urine may be frothy if it contains a large amount of protein.

If a lot of protein leaks into your urine, swelling of the legs or other parts of the body (oedema) can also develop. This is known as nephrotic syndrome.

Depending on your type of glomerulonephritis, other parts of your body can be affected and cause symptoms such as:

• rashes
• joint pain
• breathing problems
• tiredness

Many people with glomerulonephritis also have high blood pressure.

When to get medical advice

See your GP if you notice blood in your urine. This doesn't always mean you have glomerulonephritis, but the cause should be investigated.

If your GP suspects glomerulonephritis, they'll usually arrange:

• a blood test – to measure your creatinine level; if your kidneys aren't working normally, the creatinine level in your blood rises and estimated glomerular filtration rate (eGDR) falls
• a urine test – to check for blood or protein in your urine, either by dipping special strips into a sample of your urine or sending the sample to a laboratory for further testing

If glomerulonephritis is confirmed, further blood tests may be needed to help determine the cause.

If your kidney problem needs to be investigated further, it may be recommended that you have:

• an ultrasound scan – this is to check the size of your kidneys, make sure there are no blockages, and look for any other problems
• a biopsy – this is to remove a small sample of kidney tissue, carried out using local anaesthetic to numb the area; an ultrasound machine locates your kidneys and a small needle is used to take a sample

Causes of glomerulonephritis

Glomerulonephritis is often caused by a problem with your immune system. It's not clear exactly why this happens, although sometimes it's part of a condition such as systemic lupus erythematosus (SLE) or vasculitis.

In some cases, the immune system abnormalities are triggered by an infection, such as:

• HIV 
• hepatitis B and hepatitis C – viral infections of the liver
• infection of the heart valves (endocarditis)

In most cases, glomerulonephritis doesn't run in families.

If you're diagnosed with an inherited type of glomerulonephritis, 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.

Treating glomerulonephritis

Treatment for glomerulonephritis depends 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.

Medication to lower blood pressure, such as angiotensin-converting enzyme (ACE) inhibitors, is commonly prescribed because they help protect the kidneys.

If the condition is caused by a problem with your immune system, medication called immunosuppressants may be used.

Read about treating glomerulonephritis.

Complications of glomerulonephritis

Although treatment for glomerulonephritis is effective in many cases, further problems can sometimes develop.

These include: 

• high blood pressure
• high cholesterol 
• blood clots – including deep vein thrombosis (DVT) or a pulmonary embolism
• damage to other organs
• chronic kidney disease
• kidney failure

If you're diagnosed with glomerulonephritis, your doctor may prescribe medication to help lower your blood pressure, lower your cholesterol or protect against blood clots.

Treatment for glomerulonephritis depends on the cause of your condition and your symptoms.

In mild cases, treatment isn't always necessary. If treatment is needed, it's usually carried out by a kidney specialist.

Dietary changes

In mild cases, your GP or dietitian will give you relevant advice about diet. You may be advised to reduce your intake of:

• foods that contain a high amount of salt
• foods or drinks that contain a high amount of potassium
• fluid

This should help control your blood pressure and ensure the amount of fluid in your body is regulated.

You should have a regular review to ensure your blood contains the right levels of potassium, sodium chloride and other salts.

Stopping smoking

Smoking may make kidney disease caused by glomerulonephritis worse more quickly.

It also increases the risk of complications like heart disease and stroke, which are already more common in people with glomerulonephritis.

Find out more about stopping smoking.

Immunosuppressants

Severe cases of glomerulonephritis, caused by problems with the immune system, are sometimes treated with types of medicine known as immunosuppressants. These medicines suppress your immune system.

Suppressing your immune system can be effective, but it also increases your risk of infections and can cause other side effects.

If you're offered treatment with immunosuppressant medicines, they'll be adjusted to the level needed to treat your condition and will be carefully monitored.

Corticosteroids

You may be put on a course of medicines containing steroids (corticosteroids), such as Prednisolone.

Corticosteroids are used to reduce swelling and suppress your immune system.

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

Cyclophosphamide is an immunosuppressant used in very high doses to treat some cancers. It's also an established treatment, in much lower doses, for glomerulonephritis.

Other immunosuppressants

Other medicines to help control your immune system include:

• mycophenolate mofetil
• azathioprine
• rituximab
• ciclosporin
• tacrolimus

Other medicines

If your condition is thought to be linked to a viral infection, it may be treated with antiviral medication.

Individual symptoms can sometimes 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.

You may need to take medicines that lower blood pressure and help reduce the amount of protein that leaks into your urine, such as:

• angiotensin-converting enzyme (ACE) inhibitors
• angiotensin receptor blockers (ARB)

Often, people who have high blood pressure and kidney disease need to take several medicines to control their blood pressure.

These medications are commonly prescribed, even if your blood pressure is not particularly high, as they can help protect the kidneys.

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 exchange

Plasma is a fluid that is part of the blood. It contains proteins, such as antibodies that can cause your kidneys to become inflamed.

Plasma exchange involves removing some of the plasma from your blood.

During the procedure, you're 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's 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 or anti-glomerular basement membrane disease.

Read more about how plasma products are used.

Treating chronic kidney disease or kidney failure

In severe cases that can't be improved with other treatments, you may require:

• kidney dialysis – a treatment that takes over part of the kidney's job and removes waste products from your body 
• a kidney transplant – where a healthy kidney from a donor is surgically implanted to replace your own kidney

Find your local kidney unit.

Vaccinations

People with glomerulonephritis can be more prone to infections, particularly if:

• you have nephrotic syndrome
• you develop chronic kidney disease

It's usually a good idea to help protect yourself against infection by having a seasonal flu jab and a pneumonia jab.