Glomerulonephritis

Glomerulonephritis, also called GN or nephritis, is a disease of the kidneys in which the glomeruli, the tiny filters in the kidneys that help to clean the blood, become inflamed or damaged. This allows protein and red blood cells that normally circulate in the bloodstream to pass into the urine.

If glomerulonephritis does not respond to treatment, the glomeruli may slowly be destroyed. The kidneys will then lose their ability to clean your blood and this will lead to kidney failure.

What causes glomerulonephritis?

Glomerulonephritis has many different causes. In the majority of cases, the cause is unknown. However, the number of known causes has increased in recent years. It has been recognized for some time that certain infections, drugs, and - in rare cases - even cancer can lead to GN. More recently, it has been discovered that many different abnormalities in the genes of the body can also lead to the development of glomerulonephritis.

However, GN is not commonly inherited (passed on genetically from parent to child). The majority of cases of glomerulonephritis are sporadic; this means the disease arises spontaneously.

There is some evidence that GN may be caused or made worse by a problem in the body's immune system. This system protects the body against invasion by foreign materials such as viruses and bacteria. However, if the immune system is not working properly, it may damage the kidneys. The immune system may mistakenly attack the kidneys' filters (glomeruli) and cause them to become inflamed.

Types of glomerulonephritis

There are many types of glomerulonephritis. These may be grouped as primary and secondary. In primary GN, only the kidneys are affected. In secondary GN, the kidneys are damaged as part of a more generalized disease that can affect other parts of the body.

The exact diagnosis can be made by a test called a kidney biopsy. This is a medical procedure in which a very tiny tissue sample from one kidney is removed using a special needle. This tissue sample is examined to determine the pattern of kidney damage, and to give more information about the type of GN. A kidney biopsy is not required for every patient. Your kidney specialist will carry out certain tests so the right decision is made in regards to whether one is needed in your case.

Warning signs of glomerulonephritis

The presence of glomerulonephritis is difficult to detect. In the early stages, you may have no symptoms of the disease. A test to measure the protein and red blood cells in your urine will confirm whether or not you have GN.

As the disease progresses, the following warning signs may appear:

  • high blood pressure
  • excessive foaming of the urine
  • change in the colour of the urine (to red or dark brown)
  • puffiness of the eyes, hands and feet
  • nausea and vomiting
  • difficulty breathing
  • headaches

Treatment for glomerulonephritis

In mild cases, your kidneys may recover on their own. Even if the disease is more advanced, it may be slowed by lowering your blood pressure with medication and by making changes to your diet. Your kidney specialist may recommend other specific treatments as well. In rare cases, you may need temporary dialysis treatments (to clean your blood) until your kidneys recover or respond to treatment.

However, in some cases when the damage is progressive and severe, the kidneys become unable to perform their usual functions adequately, and eventually you may need regular dialysis treatments or a kidney transplant.

Screening for glomerulonephritis

You should visit your doctor regularly and have your urine tested for blood and protein. A simple test can be performed using a strip of paper dipped into the urine and analyzed right away. If a kidney problem is found, follow your doctor's advice. This will include taking any necessary medication for the treatment of GN, as well as for high blood pressure.

You should also check with your doctor before taking any over-the-counter medications. This is important because some of these, such as pain relief medications, may be harmful to your kidneys especially if they are already damaged.


With acknowledgement to Dr. Daniel Cattran, FRCPC, FACP, senior staff nephrologist at Toronto General Hospital, University Health Network in Ontario, for his assistance in reviewing this information.

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