The kidneys are a vital part of the body. Their main job is to remove waste products from the blood, which are passed out of the body in urine. There are about a million tiny filters in each kidney called glomeruli. If these filtering units get inflamed (swollen) for some reason (see causes) this is called glomerulonephritis. It means the kidneys are unable to work properly. Salt and excess fluid can build up, leading to complications such as high blood pressure and possibly kidney failure.
There are several types of glomerulonephritis; some are more serious and long-term than others. Glomerulonephritis may be short-lived (acute) and need minimal treatment. It may be present for many years without causing trouble, or it can develop into a long-term (chronic) condition.
Glomerulonephritis often follows an infection such as an infection of the throat (pharyngitis).
There are other conditions that cause glomerulonephritis and swelling in the kidneys such as infection, tumour growth, or disease within the kidney from long-term use of NSAIDs (non-steroidal anti-inflammatory drugs) such as aspirin.
Glomerulonephritis is more common in men than women. It often affects children and young people.
There are several types of glomerulonephritis. If it has been caused by an infection, the early symptoms may include a sore throat. Inflammation in the kidneys may not be obvious at first. Symptoms of kidney damage can come on suddenly or appear up to three weeks after infection.
As a result of damage to the kidneys, glomerulonephritis can cause:
a puffy face,
loss of appetite and
In addition, there may be small amounts of blood in the urine and it may be cloudy. The normal urine output for an adult is between 0.8 and 2.5 litres per day. This can vary according to a number of factors such as how much you exercise and how hot or cold you are. In severe cases of glomerulonephritis, some people find that they do not urinate at all for 2-3 days. Once they are able to urinate again, there may still be blood and protein in the urine.
Some people get pain in the kidneys (in the upper back, behind the ribs). Kidney pain may be due to a kidney infection or kidney stones and not glomerulonephritis, so it is important to see your GP for correct diagnosis.
Glomerulonephritis is usually caused by changes in the body’s immune system. This is a complicated process involving antigens and antibodies. Antigens are foreign substances in the body such as proteins and toxins. Antibodies circulate in the blood and their job is to get rid of antigens. If these antigens and antibodies gather in the kidneys for any reason it can cause an inflammatory reaction (swelling). This reaction may just affect the kidney or may cause problems in other parts of the body.
Anyone who already has a chronic (long-term) autoimmune condition, such as lupus is at risk of developing glomerulonephritis. An autoimmune condition means that the body attacks its own cells accidentally.
Commonly, acute glomerulonephritis is linked to streptococci bacteria (beta haemolytic). This is referred to as acute post streptococcal glomerulonephritis (ASGN) and can follow a throat or skin infection.
Glomerulonephritis is also recognised as a serious complication of some other infections including AIDS/HIV, Hepatitis B, Hepatitis C, TB and syphilis. For this reason, injecting drug users are particularly at risk of developing glomerulonephritis.
Glomerulonephritis is a complication of many other diseases, including:
cancer and leukaemia,
Goodpasture’s syndrome (an autoimmune disorder that affects the lungs and kidneys),
liver disease, and
sickle cell disease.
It is also recognised as a side effect of long-term use of certain drugs. Such drugs include, non-steroidal anti-inflammatory drugs (eg ibuprofen), gold injections (used in the treatment of rheumatoid arthritis), lithium (used in the treatment of depression) and penicillamine (used in the treatment of arthritis). Your GP should monitor your kidney function with renal tests if you are taking medicines that affect the function of the kidney.
Often there are no symptoms at all. Sometimes glomerulonephritis is only diagnosed following a routine medical check-up, or during tests related to having high blood pressure, feeling tired or being pregnant. If you already have kidney disease, your doctor may want to test for glomerulonephritis.
If you have glomerulonephritis, a urine test will show up blood and protein in the urine. A range of tests will be carried out to assess how well your kidneys are working (renal function tests).
These will include blood samples to find out levels of sodium, chloride, potassium and urea. Tests may show that you are producing less urine than usual overall.
If glomerulonephritis is suspected, the doctor may take a throat swab (scraping some cells from the back of your throat) a sample of to confirm the diagnosis.
Some varieties of glomerulonephritis are more serious than others. Your doctor may remove and examine a small sample of kidney tissue (a biopsy) to see how serious the glomerulonephritis is. This is usually done using local anaesthetic and a small needle. The test carries a small risk of bleeding.
Treating the original infection:
Streptococci bacteria are usually destroyed with antibiotics such as penicillin. Other infections may require other types of antibiotics and/or anti-viral drugs.
If you have glomerulonephritis the doctor treating you will focus on treating the cause as well as the condition. You may be advised to drink less fluid (restrict your fluid intake) and to avoid certain drinks such as alcohol and drinks with a lot of sodium chloride (salt) and/or potassium in them. Your diet should be controlled carefully. Your GP or dietician will give you advice on eating protein and controlling your intake of potassium and salt. Your blood chemistry will be regularly reviewed to ensure that levels of potassium, sodium and chloride are at the right level and that the amount of fluid in your diet is correct. Your treatment may include corticosteroids and a drug called cyclophosphamide. Other drugs used will relate to the underlying cause of the condition and the body’s response to glomerulonephritis.
Treating high blood pressure:
High blood pressure damages the kidney further and causes other health problems. Your blood pressure will be monitored by the doctor treating you and may need to take drugs such as ACE (Angiotensin Converting Enzyme) inhibitors which relax the blood vessels and reduce the workload of the heart.
Treating chronic kidney disease or kidney failure:
In cases of chronic kidney disease or kidney failure, kidney dialysis (using a machine to do the kidneys’ job of removing waste products from the body) or a kidney transplant will be needed.
Possible complications vary according to the type of glomerulonephritis but can include:
High blood pressure: This is a common complication of glomerulonephritis, because the kidneys help control the blood pressure in the body. Many people with glomerulonephritis are prescribed drugs to lower blood pressure. It is important to take these to protect the kidneys against further damage and also to reduce the risks of heart disease and stroke. If blood pressure is untreated it can lead to heart failure and fluid in the lungs (pulmonary oedema).
Disease in other internal organs: In most patients, glomerulonephritis affects only the kidneys. However, in some cases, the immune system that damages the kidneys can also affect other parts of the body, for example giving a blotchy red rash on the skin or pain in the joints. Discuss any symptoms you may have with your doctor to see if they could be related to glomerulonephritis.
If you develop a blotchy red skin rash you should see your GP immediately.
Kidney disease or kidney failure: This is rare, but glomerulonephritis can cause so much damage to the kidneys that they fail completely.
Glomerulonephritis is not generally preventable. Early detection (especially for people who have conditions linked to the disease), diagnosis and treatment are important to avoid other complications.
Streptococcal throat infections should be treated as early as possible with antibiotics, to avoid kidney damage occurring.