Urinary Tract Infection

Urinary Tract Infection

A urinary tract infection is an infection in the wee (urine). It is a common cause of fever in young children. 


Key points to remember about urinary tract infections

  • a urinary tract infection (UTI) is an infection in the urine (wee)
  • UTIs are common in children
  • UTIs can cause children to have high temperatures and become unwell
  • sometimes UTIs can make children seriously ill, especially babies and young children - see your doctor or after-hours medical centre urgently if that happens
  • babies under 12 months need investigation after a UTI to see if there is anything wrong with their urinary tract

What is the urinary tract and how does it normally work?

The urinary tract is the kidneys, ureters, bladder, and urethra.

The kidneys filter and remove waste and water from the blood to produce urine. The urine travels from the kidneys down 2 narrow tubes called the ureters. The urine is then stored in the bladder.

When your child does a wee, urine flows out of the body through the urethra, a tube at the bottom of the bladder. The opening of the urethra is at the end of the penis in boys and in front of the vagina in girls.

Front view of the urinary tract

Diagram showing front view of the urinary tract

Side view of the female urinary tract

Diagram showing side view of the female urinary tract

Side view of the male urinary tract

Diagram showing side view of the male urinary tract

What is a UTI?

A UTI (urinary tract infection) is an infection in the urine (wee). It usually starts in the bladder and sometimes affects the kidneys.

What causes a UTI?

A UTI usually develops when germs (bacteria) from the poo, which are on the skin, get into the urethra and into the bladder. This can happen to any baby or child and is not due to poor hygiene.

What puts my child at risk of getting a UTI?

UTIs are common. They are most common in babies under the age of 12 months but can affect children of any age.

There are some conditions which put babies and children at higher risk of UTIs:

  • constipation
  • an abnormality of the urinary tract
  • neurological conditions where the bladder doesn't empty properly

What are the signs and symptoms of a UTI?

Symptoms in children

Children with a UTI may have the following symptoms:

  • pain on doing a wee
  • wanting to wee frequently (but not much wee coming out)
  • pain in the lower part of the tummy
  • pain in one side of the lower back
  • smelly wee
  • cloudy wee
  • blood in the wee
  • vomiting
  • fever
  • feeling generally unwell often with loss of appetite
  • bedwetting, if previously dry
  • wetting during the day when previously dry

Symptoms in babies and young children

Babies and young children can't tell you about their discomfort when doing a wee and you may not notice them going more frequently. Signs of a UTI in babies and young children can include:

  • fever (with no obvious cause such as a rash or cough)
  • irritability
  • poor feeding
  • vomiting
  • being very tired and lacking energy (lethargic)
  • poor weight gain
  • jaundice in newborn babies which continues for more than 2 weeks

Signs of more serious infection in young babies and children

Sometimes a simple UTI can become more serious in young babies or children when the infection spreads to involve the kidneys, or spreads into the blood stream. If this happens, see your family doctor or after-hours medical centre urgently. Signs of this can include:

  • high fever
  • not feeding
  • tummy pain
  • repeated vomiting
  • shivering
  • drowsiness

How is a UTI diagnosed?

Testing your child's urine is the only way to know for sure if they have a UTI. Your family doctor can arrange a urine test for your child.

What is the treatment for a UTI?

Antibiotics are the main treatment for UTIs. Treatment is usually for 3 to 7 days. This depends on several factors, including how unwell your child is and whether they have underlying kidney problems.

Encouraging your child to drink more fluid may help. You can give pain relief (paracetamol) if your child is in discomfort. You must follow the dosage instructions on the bottle. It is dangerous to give more than the recommended dose.

The following babies and children with a UTI usually need to go to hospital for intravenous antibiotics (given directly into a vein):

  • young babies under 3 months of age
  • children who are very unwell

Your child's symptoms should start to improve after 48 hours of antibiotic treatment.

What other tests may be needed?

If your baby has had a UTI and is under 12 months of age, they may need further tests.

Renal ultrasound scan

The most common investigation is a renal ultrasound. This is to find out if there are any blockages and to check if the kidneys are normal in shape, size and position.

Other investigations

A small number of babies and children may need an MCU (micturating cysto-urethrogram) or a nuclear medicine scan.

A specialist at the hospital needs to request these tests.

When should I seek help for my child's UTI?

When to see your family doctor

You should see your family doctor if:

  • you think your baby or child has a UTI
  • your baby or child with a UTI is not improving after 48 hours of treatment (they may need a different antibiotic)

When to see your family doctor or after-hours medical centre urgently

You should see your family doctor or after-hours medical centre urgently if your baby or child:

  • has a high fever
  • is not feeding
  • has tummy pain
  • has repeated vomiting
  • is shivering
  • is drowsy
  • is under 3 months of age

When to dial 111

Dial 111 within New Zealand for urgent medical help if you are very concerned about your child. Use the appropriate emergency number in other countries.

What can I do to help prevent UTIs in my child?

Suggestions that may help some children

Parents often want to know what they can do to prevent UTIs. Not all UTIs can be prevented, but here are some suggestions that may help some children:

  • treat any constipation (children who have constipation are at higher risk of developing a UTI)
  • encourage your child to go to the toilet regularly when they feel the need (children who hold on a long time are more at risk of UTIs)
  • encourage your child to sit properly on the toilet with their feet on a stool so that they empty their bladder completely
  • make sure your child drinks plenty of water with meals, and during hot weather
  • teach girls to wipe their bottoms from front to back rather than back to front (to reduce the spread of germs from the bowel to the opening of the urethra)

There is a suggestion in studies of UTI in boys that circumcision might slightly reduce the incidence of UTI. But the benefit is small. Most specialists would not recommend circumcision for this reason unless there are repeated UTIs which are causing major health problems.

Avoiding things that may irritate your child's bottom

Try to avoid anything that may cause irritation to your child's bottom:

  • avoid giving your child bubble baths, especially if they have sensitive skin
  • wash your child's hair in the shower rather than in the bath so they don't sit in soapy water
  • check for threadworms, which are very common in children, and consider treating your child every 6 months
  • encourage girls to wear cotton underwear

Graphics of the urinary tract have been reproduced from NKUDIC (the National Kidney and Urologic Diseases Information Clearinghouse), United States. (These images are in the public domain; reproduction permitted).
Website: https://www.niddk.nih.gov

This page last reviewed 02 December 2019.

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