Definition of Urinary tract infection - children:

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
• Kidney infection
• Urinary tract infection - adults

Causes, incidence, and risk factors:

Most urinary tract infections (UTIs) occur in the lower urinary tract, which includes the bladder and urethra. In most cases, bacteria infects the area, and leads to inflammation.

In boys, UTIs are most common before the first birthday. In young girls, UTIs are most common around age 3, around the time they begin toilet training.

UTIs in children may be caused by problems in the urinary tract, including vesicoureteral reflux -- a problem with a valve in the bladder that allows urine to back up into the ureters and kidneys.

The following increase a child's chance of developing a UTI:

• Constipation
• Enlarged bladder
• Family history of vesicoureteral reflux or kidney disease
• Fever that keeps returning and has no clear cause
• Growth (mass) in the abdomen
• High blood pressure
• History of UTI
• Myelomeningocele or other defect of the spine
• Poor growth
• Poor urine flow
• Problems urinating (dysfunctional voiding)
• Structural problem in the urinary tract