Symptoms and signs

Blood in the urine

When red blood cells leak through the kidney’s filters into the urine, this causes haematuria (blood in the urine). Sometimes you cannot see the blood, but if there is a lot, the urine may be coloured red or dark brown (like blackcurrant squash or a cola drink).

Protein in the urine

When proteins leak through the kidney’s filters into the urine, this causes proteinuria (more protein in the urine than normal). You cannot usually see the protein, but occasionally it can make the urine look frothy.

Protein is an important part of our diet and is in most foods. When we eat protein, it is digested (broken down) in the stomach and gut and taken into the blood.

Problems urinating

Some children urinate less often or pass smaller amounts.


Some children have swelling or puffiness in different parts of their body, especially around their eyes, legs and feet oedema.
The swelling happens because there is too much fluid (liquid) in the body’s soft tissues.

In PIGN, the damaged kidney filters (glomeruli) cannot filter enough water and salt out of the blood into urine. After a while, there is too much salt and water in the body, which causes the swelling.

Swelling in the tummy and breathlessness

  • A few children get a large swelling around their tummy (ascites). It happens when fluid builds up in the peritoneal cavity, which is the area around the organs in the abdomen (tummy).
  • A very small number of children feel breathless. This happens when fluid builds up around their lungs.

If your child has PIGN and a very swollen tummy or feels breathless, contact your doctor as soon as possible.

Other symptoms and signs

The below symptoms and signs are occasionally found in children with PIGN:

  • feeling tired, low energy or difficulty concentrating
  • decreased appetite (not wanting to eat)
  • nausea (feeling sick) or vomiting (being sick), or diarrhoea
  • pain in the tummy
  • headaches that keep coming back or that do not go away.
  • pain, stiffness or swelling of the joints.


Some children have more complications – health problems that happen because of the condition or its treatment. These are more rare. Your child’s healthcare team will carefully check for these, and speak with you about any treatment that your child may need.

High blood pressure

PIGN can cause hypertension, blood pressure that is too high. In some children, this causes headaches, vomiting or blurred (fuzzy) vision. Hypertension that lasts a long time can also increase the risk of getting heart diseases in adulthood.

Rapidly progressive glomerulonephritis

Occasionally, PIGN gets worse quickly – this is called rapidly progressive glomerulonephritis (RPGN) or crescentic glomerulonephritis.

If this happens, your child will need to take medicines and may need more intensive treatment, such as dialysis. Many children with RPGN will get better, but a few will need long-term dialysis and kidney transplant.

This is one cause of acute kidney injury (AKI) – when the kidneys quickly stop working as well as they should, over a short time.