In many cases, the exact cause of glomerulonephritis is unknown. It is thought that the condition is often caused by the immune system, the body’s natural defence system against illness and infection.
The immune system
The job of your immune system is to recognise infections early and get rid of them. Your immune system has two main "tools" to use in the fight against infection. These are:
- proteins called antibodies
- a type of white blood cell called lymphocytes
Both antibodies and lymphocytes circulate in your blood. They stick to substances found on bacteria and viruses, helping get rid of them.
Abnormalities in the immune system
Many of the body’s own chemicals, such as proteins, can be similar to those found on organisms that cause infections, such as bacteria and viruses. Your immune system can mistake these proteins for an infection and attack the cells that carry them. This causes disease.
Glomerulonephritis can be caused by either abnormal antibodies or lymphocytes, or sometimes both. The exact cause of many types of glomerulonephritis is not known. However, in such cases, the cause is known to be related to the immune system working abnormally.
The types of glomerulonephritis that are caused by the immune system reacting against the body’s own proteins and other chemicals are:
- systemic lupus erythematosus - where the immune system attacks many of the body’s tissues and organs
- anti-glomerular basement membrane disease, also known as Goodpasture’s disease - where antibodies attack the membranes of the glomeruli
- immunoglobulin A nephropathy, also known as IgA nephropathy and Berger disease - where a build-up of an antibody called immunoglobulin A damages the kidneys
- membranous nephropathy (when not caused by medication, cancer or certain infections) - where the membranes of the glomeruli thicken, damaging the kidneys
- vasculitis, such as Wegener’s granulomatosis - where the immune system attacks the blood vessels in and around the glomeruli
Although it is not certain, the immune system may also play a role in causing:
- 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)
- focal and segmental glomerulosclerosis - where there is inflammation and scarring of the glomeruli
Complications of certain infections
It is possible to develop glomerulonephritis as a serious complication of various infections, including:
Inherited glomerulonephritis
Most people who develop glomerulonephritis do not have a family member with the condition. However, certain types of glomerulonephritis can run in families.
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.
Long-term medication use
While certain medicines can affect the function of the kidneys in various ways, they are rarely the cause of glomerulonephritis.
If you are taking medicines that affect your kidney function, your GP or hospital specialist will monitor this with tests (see Glomerulonephritis - diagnosis).
Other causes of glomerulonephritis
Glomerulonephritis can sometimes occur if the glomeruli are damaged by another condition, including:
Antibodies
Antibodies are proteins that are produced by the body to neutralise or destroy disease-carrying organisms and toxins.
Immune system
The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.
Inflammation
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.
Kidneys
Kidneys are a pair of bean-shaped organs located at the back of the abdomen, which remove waste and extra fluid from the blood and pass them out of the body as urine.
Lymphatic system
The lymphatic system is made up of a network of channels and glands distributed throughout the body. It helps fight infection and drain excess fluid from tissue.
