Overview, Causes, & Risk Factors
Urinary tract infection (UTI) is the term for an infection that begins in the kidney, bladder, or urethra.
What is going on in the body?
The kidneys filter and remove waste products and water from the body, and produce urine. Urine travels from the kidneys through two narrow tubes called ureters down to the bladder, where it is stored. When the bladder becomes full, it empties the urine through the urethra to the outside of the body. The urethra is a small tube at the bottom of the bladder. The opening of the urethra is at the tip of the penis in boys and in front of the vagina in girls. The urinary tract is normally free of germs. When bacteria do get in, they can infect and inflame the urethra, bladder, ureters, or kidneys.
What are the causes and risks of the condition?
UTIs are usually caused by bacteria that enter the urinary tract through the urethra and bladder. The bacteria can come from the skin around the genital area and anus. Some children may be prone to UTIs, just as some are prone to colds or ear infections.
Sometimes UTIs are a sign of an abnormality in the urinary tract. Normally, urine flows from the kidneys down the ureters and into the bladder. If the urine flow is blocked, the urinary tract can get infected. This kind of obstruction can be caused by kidney stones or by a narrow urethra or ureters.
UTIs can also occur if the urine flows up the ureters as well as down. This is usually caused by an abnormality in the way the ureters are inserted into the bladder. The condition is called vesicoureteral reflux.
Girls are more likely to get UTIs because they have shorter urethras than boys. Boys that are uncircumcised may also be at risk for UTIs.
Symptoms & Signs
What are the signs and symptoms of the condition?
The symptoms of urinary tact infections can vary with a child's age. Babies and very young children can't tell anyone where the discomfort is. They may have:
a high fever, usually more than 101 degrees F
sometimes, a low-grade fever, under 100 degrees F
loss of appetite
nausea and vomiting
signs of just not feeling well
urine in the diaper that smells
Older children's symptoms may include:
pain in the abdomen or pelvis
pain under the side of the rib cage, or flank pain
pain in the lower back
crying or complaining of pain or burning with urination
urine that looks cloudy or smells
small amounts of urine, just a few drops at a time
leaking urine into the underwear
urinating more frequently than usual
blood in the urine, or a pink tinge to the urine
Diagnosis & Tests
How is the condition diagnosed?
After doing a physical examination on the child and listening to the history of symptoms, the healthcare provider will order tests on the child's urine. Different methods are used to collect the urine, depending on the child's age. Urine must be collected in as sterile, or bacteria-free, a manner as possible.
Children who are toilet-trained are asked to urinate into a sterile container after cleaning themselves. In younger children, it may be necessary to pass a small tube, or catheter, into the urethra to get a sterile urine sample. Sometimes, a needle is inserted directly into the bladder through the skin of the lower abdomen to get a sample.
On occasion, a collection bag is used in children who are not yet toilet-trained. The collection bag is placed over the genital area until the child urinates.
A urinalysis is first done on the urine. This test checks for abnormal blood cells and for bacteria in the urine. After a urinalysis, a urine culture may also be done. This test can identify the specific type of bacteria causing the infection. The urine is left on a special dish to allow the bacteria to multiply. The larger number of bacteria makes it easier to identify them. Different antibiotics can be used on the bacteria to figure out which one works best. This helps the healthcare provider choose the best medication to treat that particular infection.
Prevention & Expectations
What can be done to prevent the condition?
There are several ways to decrease the spread of bacteria in the urinary tract. Girls should be taught to wipe from front to back, especially after a bowel movement. Children should drink plenty of fluids during the day, especially water. This helps to wash out the kidneys and bladder. Children should empty their bladders at least once every 3 to 4 hours. It may also help to avoid bubble baths and tight-fitting clothes.
What are the long-term effects of the condition?
Unless UTIs are treated promptly, serious long-term kidney damage can result. The damage may include scarring, poor function and growth of the kidneys, and high blood pressure.
What are the risks to others?
UTIs are not contagious and pose no risks to others.
Treatment & Monitoring
What are the treatments for the condition?
Antibiotics are given to treat urinary tract infections. A child may begin to feel better soon after starting the antibiotic. But it is very important to finish taking the full course of antibiotics. If kidney abnormalities are found, further treatment may be needed.
Some children have to be admitted to the hospital for treatment. This is needed if a child is extremely ill, or is unable to keep down liquids or take antibiotics. Very young children may need to be admitted for intravenous antibiotics. Sometimes an older child does not get better on antibiotics by mouth and will also need an intravenous antibiotic.
What are the side effects of the treatments?
Side effects of antibiotics include stomach upset and allergic reactions, such as rash and difficulty breathing.
What happens after treatment for the condition?
Further testing will be needed in children with a UTI if the child:
is a boy
is less than 1 year old
is a girl with a kidney infection
is a girl in whom the antibiotics do not work as well as expected
has multiple UTIs
Several different tests may be done:
A kidney and bladder ultrasound uses sound waves to look for certain abnormalities in the kidneys.
A voiding cystourethrogram (VCUG) shows the urethra and bladder while the bladder fills and empties. A liquid is put into the bladder through a catheter or tube inserted through the urethra. An x-ray shows the liquid traveling through the bladder and urethra. This test can reveal abnormalities of the inside of the urethra and bladder. It can also tell if there is any vesicoureteral reflux, with urine traveling the wrong direction up the urinary tract.
An intravenous pyelogram is a way to examine the whole urinary tract. A liquid is injected through an IV, a tube inserted into a vein. Then an x-ray follows the liquid as it flows through the urinary tract system. This test may reveal obstructions.
A nuclear scan uses radioactive materials injected into a vein. An image is made that shows how well the kidneys work, how the kidneys are shaped, and how urine drains from the kidneys. These scans usually do not expose a child to any more radiation than an x-ray.
How is the condition monitored?
Children with UTIs are monitored to make sure the treatment has worked. Untreated UTIs can lead to very serious kidney damage. It's very important to let the healthcare provider know if symptoms continue or come back.