Symptoms of acute kidney injury (AKI)

The symptoms in AKI are different in different children, depending on what is causing the AKI and how severe it is.

Sometimes there are no symptoms.

If your child has any of the below, he or she does not necessarily have AKI or another kidney condition.

If your child has any of the below, take him or her to your doctor as soon as possible.

Blood in the urine

Normally there is no blood in the urine – if there are any blood cells in the urine, this is called haematuria. Sometimes you cannot see the blood, but if there is a lot, the urine may be coloured red (like blackcurrant squash) or dark brown (like a cola drink). 

Problems urinating (weeing)

Your child may urinate a very small amount (this is called oliguria) or not at all (anuria).

Oedema (swelling)

Oedema is swelling or puffiness in different parts of the body – in children, the swelling is often seen around the eyes and on the legs and feet. 

This happens in some children who have AKI that is caused by glomerulonephritis, which is a group of conditions affecting the kidney filters, the glomeruli. In some types of glomerulonephritis, the damaged glomeruli are not able to filter enough salt and water out of the bloodstream into the urine. After a while, there is too much salt and water in the body, which causes the swelling.

Other symptoms and signs of AKI

Some children may:

  • feel tired, have low energy or have difficulty concentrating
  • get out of breath easily
  • feel nauseous (sick) or vomit (be sick), or have diarrhoea
  • feel very thirsty
  • get dizzy
  • gain weight.

Some children may not eat enough food, and some babies may not feed properly. 

In serious cases, some children have a seizure (also called a fit or convulsion).

Complications of AKI

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

AKI can cause hypertension, blood pressure that is too high. Your doctor or nurse can check your child’s blood pressure. In some children, this leads to headaches, vomiting or blurred (fuzzy) vision. Hypertension that lasts a long time can also increase the risk of getting heart disease in adulthood.

Children with hypertension will need to control their blood pressure so it is in healthy range. They may need to reduce the amount of salt they eat, or make other changes to their diet. Some children take medicines to help control their blood pressure.

Too much fluid in the body

When the kidneys stop working in AKI, this can cause too much fluid (water) in the body – this is called fluid overload.

Rarely, fluid can build up in the lungs, which may cause breathlessness – this is called pulmonary oedema.

Other, rare complications

  • Some children get an infection in their blood – this is called septicaemia
  • We need the right amounts of important chemicals – such as potassium – in our bodies. When the kidneys stop working, this can cause too much potassium in the body – this is called hyperkalaemia.
  • Damaged kidneys can also cause acid to build up in the body – this is called acidosis. This may cause rapid breathing.