Normal urine is sterile and has no bacteria in it. But bacteria cover the skin and are found in large numbers in the rectal area and in stools. Bacteria may, at times, travel up the urethra into the bladder. When this happens, the bacteria multiply and, unless the body gets rid of the bacteria, may cause infection.
There are 2 basic types of UTIs: bladder infection and kidney infection. When the infection is in the bladder, it can cause swelling and pain of the bladder. This is called cystitis.
If the bacteria travel up from the bladder through the ureters and reach and infect the kidneys, the kidney infection is called pyelonephritis. Kidney infections are more serious than bladder infections, and can harm the kidney, especially in young children.
Many children who get urinary tract infections have normal kidneys and bladders, but abnormalities should be found as early as possible in life to help protect the kidneys. Two common abnormalities are:
Urine normally flows from the kidney down the ureters and into the bladder. This one-way flow is usually maintained because of a "flap-valve" where the ureter joins the bladder. With vesicoureteral reflux, the urine flows backwards from the bladder up the ureters to the kidneys. This urine may carry bacteria from the bladder up to the kidneys and cause a more serious kidney infection (pyelonephritis).
Urine flow may get blocked at many places in the urinary tract. These blockages are mostly caused by abnormal narrow areas in the urinary tract that prevent normal flow of urine out of the body.
Can UTIs be Prevented in Children?
If your child has a normal urinary tract, certain habits can help prevent UTIs. Draining the bladder often is one of the body’s best defenses against UTIs. Drinking more fluids will increase urine flow to flush infection out of the body. Some children are more prone to getting UTIs, and low dose antibiotics can help. Treatment of constipation also helps.
In babies and small children, changing diapers more often can help prevent UTIs. When children start toilet training, it is important to teach them good bathroom habits. After each bowel movement, girls should wipe from front to rear — not rear to front. This keeps germs from spreading from the anus to the urethra. Children should also avoid “holding it in” if they need to urinate and can reach a bathroom. Urine sitting in the bladder too long gives bacteria a good place to grow.