Patient information: Urinary tract infections in children

URINARY TRACT INFECTION OVERVIEW

The urinary system includes two kidneys (that filter urine), two ureters (that move urine from the kidneys to the bladder), the bladder (that holds urine), and the urethra (that carries urine out of the bladder) (figure 1). Bacteria (germs) do not normally live in these areas. When bacteria enter these areas and multiply, an infection can develop. These infections are called urinary tract infections (UTI).

Infections involving the kidney are the most serious because, if not treated quickly, they can permanently damage the kidneys. Damage to the kidney can lead to high blood pressure and kidney failure later in life.

Urinary tract infection in adolescents and adults is discussed separately. (See "Patient information: Bladder infections in adolescents and adults".)

URINARY TRACT INFECTION CAUSES

In healthy children, most UTIs are caused by E. coli bacteria, which are normally found in stool. These bacteria can move from the anus to the urethra and into the bladder (and sometimes up into the kidney) causing infection.

Risk factors — Some children have a higher chance of developing a UTI. The following are some risk factors for UTI:

• Young age; boys younger than one year old, and girls younger than four years of age are at highest risk
• Being uncircumcised; there is a four to 10 times higher risk of infection in uncircumcised boys. Still, most uncircumcised boys do NOT develop UTIs. (See "Patient information: Circumcision in male infants".)
• Having a bladder catheter for a prolonged period of time
• Having parts of the urinary tract that did not form correctly before birth
• Having a bladder that does not work properly.
• Having one UTI makes it more likely to have another UTI.

URINARY TRACT INFECTION SYMPTOMS

Symptoms of a urinary tract infection depend on the child's age.

Older children — Children older than two years often have:

• Pain or burning when urinating
• Frequent need to urinate
• Discomfort in the lower abdomen or sides of the back (figure 2)
• Fever (greater than 100.4ºF or 38ºC) (see "Patient information: Fever in children")

Younger children — Symptoms in children younger than two years may include one or more of the following:

• Fever, which may be the only symptoms
• Foul-smelling urine
• Vomiting or diarrhea
• Irritability or fussiness
• Poor feeding, poor weight gain

URINARY TRACT INFECTION DIAGNOSIS

Children who have signs or symptoms of UTI should be seen by a healthcare provider within 24 hours. Delaying treatment can increase the risk of damage to the kidneys.

Urine testing — A urine sample is needed to confirm the diagnosis of UTI. In young children who are not toilet trained, it is usually necessary to insert a thin sterile tube (a catheter) into the urethra and bladder to obtain a urine sample. If it is not possible to catheterize the child, the provider can insert a small needle through the lower abdomen, into the bladder, and withdraw a sample of urine; this is more likely to be necessary in newborns.

In older children who can use the toilet, the urine sample is usually obtained by cleaning the area where urine exits and then having the child urinate into a sterile container.

After obtaining the urine, a urine dipstick test is usually done in the office. If the test suggests that a UTI is present, the provider will send a urine sample to the lab for urine culture to confirm the diagnosis. The culture tells the doctor which germ is causing the infection. It also helps decide which antibiotic is best. It takes up to 48 hours for germs to grow, so the culture results are not available right away.

Based on the child's signs and symptoms and the results of the dipstick test, the healthcare provider may decide to start antibiotics before urine culture results are available.

Imaging tests — Imaging tests can help the doctor to see if the urinary system did not form correctly before birth. Abnormalities of the urinary system often cause children more likely to have UTIs. The most frequently done tests are a kidney ultrasound and a voiding cystourethrogram (VCUG). Imaging tests are generally done in younger children (less than three to five years old) or in children who have had more than one UTI.

Kidney ultrasound — Ultrasound uses sound waves to create a picture of the kidneys. During the test, gel is applied to the skin on the child's back and abdomen and a small wand-like device is pressed against the body. The test is not painful and usually takes less than 30 minutes.

Voiding cystourethrogram — A voiding cystourethrogram (VCUG) is an x-ray test that shows the outline of the child's bladder and urethra. The test can also show if urine flows from the bladder backwards into the ureters or kidneys; this is called vesicoureteral reflux (picture 1). Reflux may increase the chance that a child will have kidney infections, although further study is needed to confirm this.

This test takes about one to two hours to complete and involves putting a catheter into the child's bladder. Dye is injected into the child's bladder and x-rays are taken before and after the child urinates.

URINARY TRACT INFECTION TREATMENT

Antibiotics are used to treat UTIs. The best antibiotic depends upon the child's age, the germ that causes the UTI, and the resistance that germs have. Most children who are older than two months are given an antibiotic that is taken by mouth, in a liquid or chewable tablet.

If the child is less than two months old, or if the child is vomiting and unable to take medicine by mouth, it may be necessary for the child to be admitted to the hospital for treatment with intravenous (IV) antibiotics.

Antibiotics are usually prescribed for a total of five to 14 days. In all cases, it is important for the child to take each dose of the antibiotic on time and to finish all of the medicine.

Response to treatment — Symptoms of a UTI should begin to improve within 24 to 48 hours of antibiotic treatment. If the child does not improve or worsens, he or she should be seen again by a healthcare provider. Most children who have a UTI have no long-term damage to the urinary tract as a result of the infection.

URINARY TRACT INFECTION PREVENTION

About 8 to 30 percent (one in five to 10) of children who have a UTI develop another UTI. This usually happens within the first six months after the first infection and is more common in girls.

If the child has reflux, wet underwear (due to leakage of urine), or constipation, these problems should be evaluated and treated to prevent more UTIs. (See "Patient information: Constipation in infants and children".)

Cranberry juice has been shown to be somewhat effective in preventing recurrence of UTIs in healthy adult women [1]. However, this has not been proven in children.

Preventive antibiotics — A low daily dose of an antibiotic may be recommended for children with abnormalities of the urinary tract, and sometimes for children who have had more than one UTI (and a fever), even if there are no abnormalities of the urinary tract [2].

Repeat urine testing — It is not necessary to repeat a urine test after a child has completed antibiotic treatment, as long as the UTI symptoms have resolved.

WHEN TO SEEK HELP

The following is a list of signs and symptoms that require evaluation for a possible urinary tract infection:

• Fever — Fever may be the only symptom of urinary tract infection in infants and young children. In addition, any young child with a previous UTI who develops a fever should be evaluated for a urinary tract infection within 24 hours.
• Complaints of pain or burning with urination or frequent urination
• Back or abdominal pain

WHERE TO GET MORE INFORMATION

Your child's healthcare provider is the best source of information for questions and concerns related to your child's medical problem. Because no two people are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your child's situation.

This discussion will be updated as needed every four months on our web site (www.uptodate.com/patients). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

Some of the most pertinent include:

Patient Level Information:
Patient information: Bladder infections in adolescents and adults
Patient information: Circumcision in male infants
Patient information: Fever in children
Patient information: Constipation in infants and children

Professional Level Information:
Acute cystitis in children older than two years and adolescents
Acute management of nephrolithiasis in children
Acute management, imaging, and prognosis of urinary tract infections in children
Clinical features and diagnosis of nephrolithiasis in children
Clinical features and diagnosis of urinary tract infections in children
Epidemiology and risk factors for urinary tract infections in children
Evaluation of dysuria in children
Long-term management and prevention of urinary tract infections in children
Management of vesicoureteral reflux
Presentation, diagnosis, and clinical course of vesicoureteral reflux
Prevention of recurrent nephrolithiasis in children
Urinary tract infections in newborns
Urine collection techniques in children

A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.

• National Library of Medicine

      (www.nlm.nih.gov/medlineplus/healthtopics.html)

• The Centers for Disease Control and Prevention

      (www.cdc.gov/)

• National Institute of Diabetes and Digestive and Kidney Diseases

      (www.niddk.nih.gov)

• The American Academy of Pediatrics

      (www.aap.org)

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