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Kidney & Urinary System


Lea este articulo en EspanolThe kidneys are fist-sized organs in the back that are shaped like kidney beans. They filter blood and help remove waste products from the body. Tiny filtering units within the kidneys do this with the help of blood vessels called glomeruli. When the glomeruli become inflamed, it’s called glomerulonephritis.

Glomerulonephritis (gluh-MARE-you-low-ne-FRY-tis) causes the kidneys to stop working properly, which can cause swelling (edema) throughout the body and other symptoms. Glomerulonephritis can be acute (coming on suddenly) or chronic (developing over several years). Often, people don’t know they have glomerulonephritis until a routine urine test detects it.

Many cases of glomerulonephritis get better on their own. Those that don’t will require treatment, which usually is very effective. Untreated glomerulonephritis can lead to kidney failure or chronic kidney disease, although this is rare.

How the Kidneys Work

Kidneys work a lot like a garbage collection and disposal system. The body doesn’t use everything that we eat and drink, and this creates waste products. Some of that waste ends up in the blood, along with other waste products from chemical reactions in the body. Kidneys filter the blood and remove excess fluids and waste products by passing them out of the body as urine (pee).

The blood filtering happens in tiny structures called nephrons. Each kidney has about a million nephrons, and each nephron has one glomerulus (the singular of glomeruli), a ball of microscopic blood vessels, or capillaries. The glomerulus is the nephron’s filter, where the process of removing waste products and fluids from the blood begins.

If someone’s glomeruli aren’t doing their job properly, it can cause a number of problems for the kidneys and affect overall health.


Causes of acute glomerulonephritis include:

  • conditions that affect the immune system (such as lupus or HIV)
  • conditions that affect the blood vessels (like vasculitis or Henoch Schonlein Purpura)
  • infection with group A streptococcus (the bacteria that cause strep throat)

Doctors often know what’s causing acute glomerulonephritis, but it can be difficult to find the cause of chronic glomerulonephritis. Sometimes, doctors don’t know why people get it. In rare cases, children can inherit glomerulonephritis from their parents; this is called Alport syndrome.


With acute glomerulonephritis, symptoms come on suddenly, possibly after a skin infection or a case of strep throat. Chronic glomerulonephritis can take several years to develop and is detected through a urine test.

Early signs of glomerulonephritis include:

If the condition isn’t caught early and treated, kidney damage can occur. Symptoms of kidney damage or kidney failure include:

  • urinating more frequently
  • reduced amounts of urine
  • lack of appetite
  • nausea and vomiting
  • weight loss
  • muscle cramps at night
  • fatigue
  • pale skin
  • high blood pressure
  • headaches
  • fluid buildup in the tissues

Other conditions can cause these symptoms, so they don’t necessarily mean that the kidneys are failing. But if your child has any of these symptoms, it’s important to see a doctor right away to determine the cause.


At the doctor’s office, explain your child’s symptoms. The doctor will examine your child and may take blood and urine samples for testing. The doctor also might order a kidney ultrasound to get a better look at the kidneys. Ultrasounds use sound waves to create images of organs and other body parts.

In some cases, a biopsy may be necessary. During this procedure, a tiny sample of kidney tissue is removed and sent to a lab for testing to help determine the cause of the glomerulonephritis and check for any kidney damage.


While some cases of acute glomerulonephritis go away on their own, others require treatment. The sooner treatment begins, the less damage there may be to the kidneys.

Treatment for glomerulonephritis varies depending on a child’s age and general health, how well the kidneys are functioning, and the cause of the inflammation.

Treatment may include:

  • fluid restriction (limiting the amount of fluid your child drinks in a day)
  • a diet low in protein, salt, and potassium
  • diuretics (medicines that increase urine production)
  • medicines to lower blood pressure
  • antibiotics (if a bacterial infection is causing glomerulonephritis)
  • steroids and other drugs that suppress the immune system (if an immune system problem is causing glomerulonephritis)
  • in severe cases, kidney dialysis

Chronic glomerulonephritis is a condition that either fails to respond to treatment or keeps coming back for months or even years. In these cases, doctors may recommend lifestyle changes to minimize further damage to the kidneys and slow the progression of the disease.

Lifestyle changes that can help kids with chronic glomerulonephritis include:

  • eating a healthy diet while limiting protein, potassium, and salt intake
  • getting plenty of exercise (at least 1 hour a day for kids over age 2)
  • reducing fluid intake
  • taking calcium supplements


In most cases of acute glomerulonephritis, the damage to the glomeruli will eventually heal. The length of time it takes depends on what caused the glomerulonephritis, how long it lasted, and when treatment began.

In rare cases, glomerulonephritis can lead to kidney failure that requires dialysis or a kidney transplant. Fortunately, most kids will never need those procedures and will be able to play sports, participate in favorite activities, and lead perfectly normal lives.

Reviewed by: Robert S. Mathias, MD
Date reviewed: May 2013