Urinary tract infections

This page from Great Ormond Street Hospital (GOSH) is about urinary tract infections in young people with abnormal urinary tracts. A urinary tract infection (UTI) is an infection of one of the various parts of your urinary system.

The urinary system consists of the kidneys, ureters, the bladder and urethra. The kidneys filter the blood to remove waste products and produce urine.

The urine flows from the kidneys down through the ureters to the bladder, where It’s stored until we go to the toilet. It passes through another tube called the urethra to the outside when urinating (peeing).


Some children are born with a problem with the urinary tract. There can be different malformations, such as posterior urethral valves, hydronephrosis and hydroureters or severe vesico-ureteric reflux.

All of these malformations have one thing in common: they stop urine flowing normally. It can be slow because of an obstruction or narrowing of the ureter, for instance. There can also be ‘residual urine’, which means that the bladder doesn’t empty properly when peeing, leaving some urine behind.

If children have a problem with their urinary tract, they are at a greater risk of having urinary tract infections.

A UTI will have more impact on children if they have a known problem.

Types of UTI

There are three types of UTI:

Acute pyelonephritis

Pyelonephritis means ‘kidney infection’.  It’s very important to diagnose and treat pyelonephritis quickly because it can cause kidney damage. The main sign of a kidney infection is a very high temperature. The child may also have symptoms of feeling generally unwell, such as vomiting, drowsiness or pain affecting the stomach or sides.

If the child develops an unexplained fever or any of these symptoms, they should see a doctor and make sure that their urine is tested for infection.

If the child has an infection, the doctor should prescribe a course of antibiotics to treat the infection. Children should always ensure that thet finish the course of antibiotics, even if they feel better. If they don’t complete the course of antibiotics, this could allow the infection to come back and possibly not respond so well to antibiotics the next time.

Acute cystitis

This means ‘inflammation of the bladder’. The child may experience pain in the stomach and discomfort when peeing. Their urine might have blood in it, and might be a reddish or pinkish colour.

Generally, if children have a bladder infection they won’t have as high a temperature as a kidney infection, but might still feel unwell. The infection needs treatment to take away the pain and although it doesn’t cause kidney damage, if it isn't treated it can lead to a type of kidney infection called pyelonephritis.

Asymptomatic bacteriuria (ABU)

This means that bacteria are growing in the child's urine, which might make their urine smelly or cloudy, but they’re not producing any other symptoms. People with normal urinary tracts sometimes get ABU, but it’s more common in people with any kind of problem with the urinary tract.

It’s not dangerous as it doesn’t have any symptoms and doesn’t lead to kidney damage. It’s also very difficult to treat. Even if antibiotics treat the bacteria, it will often come back after a few days. Antibiotics are only used when there are symptoms.


The most important thing to reduce the chances of getting an infection is to create a good flow of urine. A few things children can do to help themselves are:

  • Drink plenty of fluids.
  • Pee regularly.
  • Avoid constipation (for example, by having enough fibre in their diet).
  • Wash regularly with water or a mild soap and always wipe from front to back when going to the toilet. 
Sometimes, if a child doesn't empty his or her bladder properly, a catheter (thin, plastic tube) will be inserted into the bladder through the urethra to drain away the urine (urethral catheterisation).

Sometimes, if the child us still having repeated infections, it may be suggested that theytake long-term antibiotics for prevention.

In some situations when the urinary tract is abnormal, surgery might be recommended. This tends to be specific to each person and all options can be discussed with a doctor or nurse.

Last review date:
July 2014