Urinary tract infection (UTI) is the term for an infection that begins in the kidney, bladder, or urethra.
The kidneys filter and remove waste products and water from the body, producing 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 free of bacteria most of the time, but when they do get in, they can infect and inflame the urethra, bladder, ureters, or kidneys.
The symptoms of urinary tract infections can vary with a child's age. Babies and very young children cannot tell anyone where the discomfort is. They may have: a fever, usually, but not always, more than 101 degrees Firritabilityloss of appetitenausea and vomitingsigns of just not feeling wellurine in the diaper that smells unusualpoor weight gain
Older children's symptoms may include: pain in the abdomen or pelvispain under the side of the rib cage, or flank painpain in the lower backcrying or complaining of pain or burning with urinationurine that looks cloudy or smellssmall amounts of urine, just a few drops at a timeleaking urine into the underwearurinating more frequently than usualblood in the urine, or a pink tinge to the urine
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. Although boys that are uncircumcised may also be at risk for UTIs, a UTI in a boy calls for a thorough examination and evaluation.
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.
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 under the microscope. After a urinalysis, a urine culture may also be done. This test can identify the specific type of bacteria causing the infection. This will take 1-3 days to complete. 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.
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.
UTIs are not contagious and pose no risks to others.
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.
Side effects of antibiotics include stomach upset and allergic reactions, such as rash and difficulty breathing.
Further testing will be needed in children with a UTI if the child: is a boyis less than 1 year oldis a girl with a kidney infectionis a girl in whom the antibiotics do not work as well as expectedhas 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.
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.
Mayo Clinic Family Health Book, Larson, 1996.
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Nelson's Essentials of Pediatrics, Behrman and Kliegman, 1994, p. 608-10.