Urinary tract infection – children: Overview, Causes

Definition

A urinary tract infection (UTI) is a bacterial infection of the urinary tract. This article discusses UTIs in children.

The urinary tract includes the:

• Bladder
• Kidneys
• Ureters — the tubes that take urine from each kidney to the bladder
• Urethra — the tube that empties urine from the bladder to the outside

See also:

• Catheter-associated UTI
• Urinary tract infection – adults

Overview, Causes, & Risk Factors

Urinary tract infections (UTIs) can occur when bacteria find their way into the bladder or the kidneys. These bacteria are normally found on the skin around the anus or sometimes around the vagina.

Normally, there are no bacteria in the urinary tract itself. However, certain things can make it easier for bacteria to enter or stay in the urinary tract. These include:

• A problem in the urinary tract, called vesicoureteral reflux, which is usually present at birth. This condition allows urine to flow back up into the ureters and kidneys
• Brain or nervous system illnesses (such as myelomeningocele, spinal cord injury, hyrocephalus) that make it harder to completely empty the bladder
• Bubble baths or tight fitting clothes (girls)
• Changes or birth defects in the structure of the urinary tract
• Not urinating (peeing) often enough during the day
• Wiping from back (near the anus) to front after going to the bathroom. In girls, this can bring bacteria to the opening where the urine comes out

UTIs are more common in girls, especially around age 3 when they first begin toilet training. In boys who are not circumcised, the risk for UTIs is slightly higher before the first birthday.

Pictures & Images

The female and male urinary tracts are relatively the same except for the length of the urethra.

One method of examining bladder function is by injecting dye that is visible on X-rays through a tube (catheter) to fill the bladder. X-rays are taken while the bladder is full and while the patient is urinating (voiding) to determine if fluid is forced out of the bladder through the urethra (normal) or up through the ureters into the kidney (vesicoureteral reflux). This study is usually done with the patient lying on an X-ray table.

When the ureters enter the bladder, they travel through the wall of the bladder for a distance in such a way that they create a tunnel so that a flap-like valve is created inside the bladder. This valve prevents urine from backing-up into the ureters and kidneys.

In some children, the valves may be abnormal or the ureters in the bladder may not travel long enough in the bladder wall, which can cause�vesicoureteral reflux. Vesicoureteral reflux is a condition that allows urine to go back up into the ureters and kidneys causing repeated urinary tract infections. The reflux of urine exposes the ureters and kidney to infection from bacteria and high-pressure, which is generated by the bladder during urination.� If left untreated, urinary infections can cause kidney damage and renal scarring with the loss of potential growth of the kidney and high blood pressure later in life.

Vesicoureteral reflux is treated with antibiotics, and in severe cases surgically.

• Urinary tract infection – children: Overview, Causes

• Urinary tract infection – children: Symptoms & Signs, Diagnosis & Tests

• Urinary tract infection – children: Treatment

Review Date : 10/6/2009
Reviewed By : David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.