A urinary tract infection (UTI) is a bacterial infection of any part of the urinary tract, which includes the kidneys and bladder. UTI’s usually affect just the bladder, but can also extend up into the kidneys, which is a more severe infection.
Unlike other areas of the body (like the skin and mouth - which are usually colonized with bacteria), the urinary tract should be sterile. In other words, it is not normal to find bacteria in the urine. When bacteria are found in the urine, especially in association with specific symptoms (such as frequent and/or painful urination), a UTI is diagnosed and requires antibiotic therapy.
UTI’s are very common in children, affecting 8.4% of girls and 1.7% of boys by the age of 7. Children with UTI’s may have a variety of symptoms, including: fever, frequent and/or painful urination, and new onset incontinence or urgency (having to rush to get to the bathroom on time).
What Causes UTI’s?
All UTI’s are caused by bacteria outside of the bladder traveling into the bladder via the urethra (tube you urinate out of) in large enough numbers to attach to the bladder wall and begin to multiply. It is important to remember that all of us have bacteria growing in the area right around the opening of the urethra, but most of us do not get UTI’s. There are several reasons for this. First of all, boys have a longer urethra than girls, which provides some protection against UTI’s just because the bacteria have to travel a longer distance to get into the bladder. It is also easier for boys than girls to keep the area around their urethra clean and dry and free of irritation, which may also contribute to a higher rate of UTI in girls.
Another risk factor for UTI’s is antibiotic therapy for other illnesses. The reason antibiotic therapy for other illnesses can cause UTI’s can be explained as follows. When we are healthy, we have helpful bacteria living on the skin in the area around the urethra, which are not likely to cause UTI’s, and their presence keeps away the more dangerous bacteria (usually located in the colon), because they leave no room for the other bacteria to grow. When a child is treated for an infection with antibiotics (such as an ear infection), the antibiotics often wipe out the beneficial bacteria around the urethra as well, allowing the more dangerous bacteria to grow into the area, and often into the bladder. That is why many efforts to prevent UTI’s in children are focused on maintaining or replacing helpful bacteria.
Brenner Children's Hospital sees the biggest risk factor for UTI’s in children as “voiding dysfunction”. When children are toilet trained, they learn to hold their urine and/or stools, and since they are just kids and have other things on their minds (playing, television, etc.) they often put off urinating and/or passing bowel movements to the last possible moment. This problem, which we'll call “holding”, is very frustrating for parents and can cause a number of problems for the child.
The results of this abnormal behavior usually include daytime wetting, having to rush to the bathroom to get there on time, and constipation. These children may develop an unstable or hyperactive bladder, and often curtsey or squat to hold in their urine or stool. The high pressures that develop in the bladder due to this behavior are dangerous to the health of the kidneys and bladder. The constipation that develops from holding makes the children have hard stools that are painful to pass, reinforcing the bad behavior.
The reason this “holding” can cause UTI’s is because one of the body's defense mechanism against infections is the regular flow of the urine out of the bladder, which prevents the bacteria living around the urethra from gaining access to the urinary tract. However, if a child continually fights the urge to void, delaying bladder emptying, there is less of this urine flow to prevent bacteria from accessing the urethra. Also, when you have a strong urge to void, the bladder has already prepared itself to empty, opening the bladder neck and allowing urine into the urethra. If a child fights the urge to empty, clamping down on their urethra, the urine is directed back into the bladder as the urge subsides, allowing the bacteria that reside in the urethra access into the bladder.
It is important to remember that some children may also have an anatomic problem in their urinary tract that makes them more susceptible to UTI’s (such as reflux or obstruction), so any child with a history of a UTI needs an evaluation by a pediatric urologist.
UTI Prevention and Treatment
Active UTI’s are treated with antibiotics for 3-10 days, depending on the severity. Some children need to stay on a low, prophylactic dose of antibiotics for a short while to break the cycle of frequently recurring infections.
Children with voiding dysfunction may require medicines to relax their bladder (so they have less urgency, and can make it to the bathroom on time) or medicines to relax their bladder neck (so they empty their bladder to completion when they do void). Brenner Children's recommends all children with recurrent infections should be placed on a timed schedule of emptying their bladder every 2 hours while awake.
If there is a congenital, anatomic abnormality causing the infections, then this anomaly can often be repaired with surgery.