Children's Hospital Colorado

Glomerulonephritis (GN)

What is glomerulonephritis?

Glomerulonephritis is a condition in which the kidney filters become inflamed, causing blood to leak into urine. In acute cases, blood in the urine is visible to the naked eye.

Glomerulonephritis can occur in various forms, including infections and viruses:

  • Strep, or other infection-related glomerulonephritis
  • Membranoproliferative glomerulonephritis, a chronic (lifelong) condition.

Blood in urine may also indicate a different condition called IgA nephropathy. A kidney disease specialist for children (nephrologist) will perform lab work to determine a diagnosis.

What causes glomerulonephritis?

In some cases, the cause of this inflammation is not entirely known. Other times, it can be due to strep, other infections or viruses.

After a strep infection has been cleared out by the body’s immune system, some children’s kidney filters (glomeruli) react in the clean up process performed by the kidney. This is known as post-step glomerulonephritis. In 85% of uncomplicated cases of post-strep glomerulonephritis, there is total kidney recovery.

Other types of glomerulonephritis, including membranoproliferative glomerulonephritis, have no explained cause. IgA nephropathy also has no known cause, and can look like acute glomerulonephritis because of the blood seen in the urine. In cases of IgA nephropathy, a child can have several episodes of blood in the urine over time, without any prior infection. Like acute glomerulonephritis, kidney function recovers in 85% of cases.

Other nephritis diseases

There are other diseases that can involve the kidney filters and cause glomerulonephritis. Glomerulonephritis can be seen in diseases such as Systemic Lupus Erythematosus (SLE) and Henoch-Schonlein Purpura (HSP) that affect other parts of the body. Proven treatments are not available for every kind of nephritis, but your nephrologist will know what treatments are best. Efforts are made to treat severe cases, because losing kidney function from kidney disease is very serious.

What are the signs and symptoms of glomerulonephritis?

Acute glomerulonephritis usually presents with obvious blood (seen by the naked eye) in the urine. You may notice that your child’s urine is a rusty brown color, like dark tea or cola. Your child may not feel sick, but if you know that your child had a sore throat or some other infection a couple of weeks before this urine color change, your child may have acute glomerulonephritis.

However, if your child has blood in the urine that comes and goes, especially at times when he or she has an ongoing cold or some type of infection, they may not have acute glomerulonephritis, but IgA nephropathy instead.

What tests are used to diagnose glomerulonephritis?

Blood and urine tests are commonly used to diagnose glomerulonephritis or IgA nephropathy. The most important blood test is the one that checks for normal kidney function. It is called creatinine and helps the doctor determine if the disease is mild or severe. A test called C3 complement is also obtained to help separate acute glomerulonephritis from IgA nephropathy.

How is Glomerulonephritis treated?

In the majority of cases (85%), no treatment is needed for the glomerulonephritis itself. Sometimes there is related high blood pressure, and that does require treatment until it improves. Often your doctor will begin treating high blood pressure in this condition with the advice of the pediatric nephrologist. Your doctor may refer you to a nephrologist, especially if the disease appears to be more severe than usual.

In severe cases putting kidney function at risk, the nephrologist has the experience to suggest treatments that have been shown to help. A biopsy is not generally needed in diagnosis and treating the first signs of acute glomerulonephritis or IgA nephropathy, but your child’s nephrologist can help you decide if a kidney biopsy might be necessary. In a biopsy, a very tiny piece of the kidney is examined under a microscope to determine an exact diagnosis and identify the degree of injury to the glomeruli to see if treatment is required.


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