Post-infectious glomerulonephritis

What is post-infectious glomerulonephritis?

"Glomerulonephritis" means inflammation of the glomeruli, and "post-infectious" means that it happens after an infection.

Kidney and glomeruli

The glomeruli are the tiny filters of the kidney. The kidneys are vital organs in our bodies. Most people have two kidneys, one on each side of the spine, just under the rib cage. They are about the size of your child's fist. They filter blood to keep it clean and help keep everyone healthy in many ways:

• They turn the body’s waste products into urine (pee).
• They control the water balance in the body.
• They control the balance of other substances in the body, such as sodium, calcium and potassium.
• They produce hormones, which are messengers that help regulate bodily functions such as blood pressure.

Kidney and glomerulus

In children, post-infectious glomerulonephritis is usually caused by inflammation that follows an infection. Glomerulonephritis most commonly happens after a streptococcus infection; it is then called post-streptococcal glomerulonephritis. Streptococcus can cause strep throat or skin infection such as scarlet fever. When children have an infection, their body’s immune system is activated and produces antibodies to fight the infection. In some children, the immune system goes awry. It attacks the glomeruli and causes inflammation.

Glomerulonephritis may also result from complications from another illness, such as systemic lupus erythematosus, type-1 diabetes or bacterial endocarditis. This is less common in children.

Signs and symptoms of glomerulonephritis

The signs and symptoms of glomerulonephritis include:

• swelling around the eyes or limbs
• dark, foamy or cola coloured pee
• decreased peeing
• fatigue
• nausea and vomiting
• headache
• difficulty breathing

Diagnosis of post-infectious glomerulonephritis

Your child will have blood and urine tests to look at the function of the kidneys as well as the balance of fluids and electrolytes. They may also have a throat swab to look for strep throat infection.

Treatment of post-infectious glomerulonephritis

At the hospital

Most children fully recover on their own. There is no medicine to treat the inflammation of the glomeruli. Your health-care team may suggest measures to help with some of the side effects, such as a low salt diet and medicines to help manage blood pressure, and a target amount of fluid to drink per day. The doctor may prescribe to your child antibiotics to take by mouth if your child’s throat swab is positive for group A Strep (a bacterial throat infection) or if they have signs and symptoms of a current bacterial infection.

Some children will need to stay in the hospital. If your child is admitted to hospital, the health-care team will carefully watch how much they are drinking and peeing, and monitor their blood pressure and weight. The health-care team will also do the blood tests again to ensure that your child’s kidneys are able to filter the blood adequately.

At home

Your child will be followed by a pediatrician or pediatric nephrologist (kidney specialist) until symptoms have completely disappeared. This may take a long time, as long as six to 12 weeks (two to four months). They will usually have repeat urine tests to check for signs of inflammation in the kidneys.

When should your child see a doctor?

Return to the emergency department if your child has:

• headache
• visual changes, such as double or blurry vision
• new or worsening swelling
• difficulty breathing
• decreased peeing
• red urine.

If you live in Ontario and you are unsure about your child’s symptoms, you can call Health811 (811 | TTY: 1-866-797-0007).