Published: May 28, 2008
Updated: May 28, 2008
It is not uncommon for a young child to have a urinary tract infection (UTI). Parents frequently ask me how much of a problem this will be for their child in the future.
In this article, Delbert Wigfall, MD, discusses UTIs -- their causes, treatments, and possible consequences.
-- Dennis Clements MD, PhD, MPH
Urinary tract infections (UTI) can affect up to 1 percent of boys and 3 percent of girls in the first decade of their lives.
However, some groups are more at risk to have UTIs than others. Risk factors for UTI include:
Children on immunosuppressive medication or prolonged antibiotics and sexually active female adolescents are also at higher risk.
Physicians worry about urinary tract infections because when left undiagnosed, they can result in kidney damage and/or dysfunction.
It can be difficult to diagnose a urinary tract infection because the symptoms are often non-specific.
In infants, the symptoms may include prolonged fever, vomiting, irritability, reduced responsiveness or activity, and poor feeding.
When the child is verbal, he or she may complain of abdominal or loin pain, but more often describe a feeling of needing to urinate frequently (urgency and frequency) and pain on urination (dysuria).
Symptoms in older children often include unexplained fever, abdominal pain, incontinence or bedwetting in the previously toilet-trained child, and malodorous or cloudy urine.
So, when do you need to worry about possible urinary tract infections and what are long-term concerns?
Infants and children who have unexplained fevers of 100.4 degrees F (38 degrees C) or higher for more than 24-48 hours, or who have symptoms and signs suggestive of a UTI, should have a urine sample obtained to look for infection. The urine should be sterile if possible.
In older and cooperative children, a urine specimen can be obtained by collecting the urine in a sterile container after cleaning the perineum or penis and during the middle of a voiding (urinating) episode. If it is not possible to obtain a urine sample in this way (because of age or illness of the child), a sterile urine sample can be obtained by catheterization of the bladder via the urethra.
Occasionally in a severely ill child a sample is obtained by aspiration of the bladder using a needle placed in the suprapubic region (the lowest part of the abdomen -- directly over the bladder). The urine should be processed immediately after collection for optimal results.
Once obtained, the urine is examined chemically and microscopically, and cultured to look for bacteria. The chemical tests include a “dipstick” evaluation, which tests for the presence of products that might accompany a UTI (such as blood or protein) and products of the infection itself. The dipstick will also test for the products of bacteria and white blood cells.
Many, but not all, bacteria produce chemicals in the urine called nitrites, and the accompanying white blood cells that are sent there by the body to fight the infection generate products called leukocyte esterase. This can turn a test on the urine dipstick to positive and suggest that an infection is present.
Microscopically, the urine is evaluated for the presence of red and white blood cell and bacteria. It is not common for bacteria to be on the skin, so the presence of skin cells (squamous cells) in the urine examined microscopically makes the physician wary that the urine may not be a sterile collection. If the urine is not collected sterilely, the results may be contaminated by bacteria normally found on the skin and in the perineum. Sterile urine is preferred to know for sure whether an infection is present.
The definitive diagnosis of a UTI requires that the urine be cultured. The culture not only confirms the presence of an infection, but also guides the therapy given the range of organisms that may cause a UTI.
Some organisms common to UTI, including E. coli and Klebsiella, are readily treated using sulfa or ampicillin containing antibiotics. In sexually active adolescents the treatment may be complicated by the high prevalence of sexually transmitted pathogens including chlamydia and thus require other antibiotics.
The objectives of treating the UTI include symptomatic relief, eradication of the infection, and prevention of damage to the kidney by scarring. The choice of treatment depends on factors including age, clinical status, presence of vomiting, the pathogen itself, and its responsiveness to common antibiotics. In some cases, the child may require further testing (including radiographs) under the direction of a kidney specialist after an infection, especially if they are frequently affected by UTI, or have an unusual course or response to therapy.
Children that have radiographic procedures performed and in which structural abnormalities are found may require surgical intervention to help prevent new infections and damage to their kidneys. The ultimate goal of aggressive treatment of urinary tract infections, medical and surgical, is to eradicate infection, and to prevent the long term problems associated with untreated UTIs -- including hypertension and impaired kidney function.
-- Delbert Wigfall, MD, is a nephrology specialist in Duke's Department of Pediatrics.
-- Dennis Clements, MD, PhD, MPH, is the chief of primary care pediatrics at Duke Children's Hospital.