Urinary Tract Infection

James K. Todd, M.D.
Professor of Pediatrics, Microbiology, and Preventive Medicine
University of Colorado School of Medicine
Denver, Colorado

What is a urinary tract infection?

A urinary tract infection, also called UTI, refers to a bacterial infection of the
bladder (“cystitis”) or the kidneys (“pyelonephritis”).

top

What causes a urinary tract infection?

A urinary tract infection is caused by bacteria that get into the bladder from the
skin surface surrounding the urethra (the opening that urine comes out of). Because
of the proximity of the urethra to the colon, organisms like E. coli are common
causes of UTI.

top

How does it cause disease?

Once the bacteria get into the bladder, they can grow in the urine, especially if
the child does not empty the bladder frequently, or if there are structural abnormalities
of the urinary tract. If the infection of the bladder is not recognized and treated,
it can move up the ureters (the tubes that connect the bladder to the kidney) and
cause an infection of the kidneys.

top

Who gets a urinary tract infections?

In the newborn period, both boys and girls get UTI. Boys seem to be at an increased
risk if they are uncircumcised with a tight foreskin. Thereafter, UTI is much more
common in girls, presumably because they have shorter urethras, leading to more
frequent bacterial contamination of the bladder. In girls, itching caused by pinworms,
sitting in bathwater for an extended time period, bubble bath, wiping from back
to front, and sexual activity increase the likelihood of such bacterial contamination,
and thereby increase the risk of UTI. In addition, the bacteria more readily cause
infection in those girls who urinate infrequently or incompletely.

top

What are the common findings?

The symptoms of a urinary tract infection are dependent upon the age of the child.
In older children and adults, the symptoms may include a fever and back pain (i.e.,
a kidney infection), or increased frequency, urgency, or burning on urination (i.e.,
a bladder infection). Younger children may have enuresis (bed or clothes wetting)
or strong smelling urine. Babies and infants often have less specific symptoms,
such as a fever, poor feeding, and/or failure to gain weight.

top

How is a urinary tract infection diagnosed?

Most importantly, a urine specimen must be analyzed to diagnose UTI. The way the
specimen is obtained is critical to interpretation. When the child is sick, it is
recommended to get a urine specimen by catheter (inserting a thin tube up the urethra
into the bladder). Especially in younger children, bag urines, or those obtained
by having the child urinate into a cup, often are contaminated, and may confuse
the correct diagnosis.

“Clean catch” urine specimens may be useful in boys and older girls who do not have
a fever, if obtained by a health professional. The urine should be analyzed immediately
or held in the refrigerator. A preliminary “urine analysis” can be performed by
dipping a special test strip into the urine; however, it also should be cultured.
These results take 24 to 48 hours. Treatment may be started based on the urine analysis.

top

How is a urinary tract infection treated?

Oral antibiotics, taken for 10 to 14 days, are very effective in the treatment of
UTI. Antibiotics can be given at home, unless the child is very young, vomiting,
and/or very sick. Once the culture result is known, antibiotics may be changed.
Fluids should be encouraged to promote urine flow.

Often, physicians will obtain imaging (e.g., x-rays, ultrasound, or scanning) of
the urinary tract in children with UTI. This imaging may help to determine which
children require a closer follow-up, or need to see the urologist (a surgeon who
specializes in diseases of the urinary tract). Most children with UTI can be cared
for very effectively by the primary physician.

top

What are the complications?

The bacteria that cause a urinary tract infection rarely enter into the bloodstream
(“sepsis”). Recurrent kidney infections may cause scarring of the kidneys. However,
these complications are more common in children who have significant structural
abnormalities of the urinary tract.

top

How can a urinary tract infection be prevented?

Preventive measures are useful to reduce the recurrence of UTI. Children should
be treated for pinworms or constipation, if determined to be present, by a primary
physician. Girls should take showers rather than baths, and be taught to wipe from
the front to the back (to decrease fecal contamination). Little girls often tend
to “hold” their urine, which should be actively discouraged. All children should
be encouraged to drink fluids frequently and to urinate every three to four hours
(an alarm watch and/or a discussion with the child’s teacher often helps).

The primary physician may suggest follow-up appointments for urine testing, or home
follow-up using urine testing strips and urine specimens collected first thing in
the morning. Any child with a positive home test (if done) or the symptoms of UTI
should see a physician. Some children (especially the very young, those with complications,
and those with recurrences) may be put on long-term antibiotic therapy to prevent
recurrent infections, but this may result in the development of more resistant organisms.

top

What research is being done?

Current research is focused on better ways to treat and prevent UTI at home. Physicians
also are trying to identify how imaging tests can better guide the management of
UTI.

top

Links to other information

For more information on urinary tract infections, visit:
National Kidney and Urologic Diseases Information Clearing House
.

top

References

Todd JK. Prevention of urinary tract infection in children. Report on Ped ID 1997;September:7(8);29-32.

Garin EH, Campos A, et al. Primary vesicoureteral reflux: review of current concepts
(in process citation). Pediatr Nephrol 1998;12(3):249-56.

Todd JK. Home follow-up of urinary tract infection. Comparison of two nonculture
techniques. Am J Dis Child 1977;131(8):860-1.

Todd JK. Office laboratory diagnosis of urinary tract infection. Pediatr Infect
Dis 1982;1:126-131.

Hoberman A, Wald ER. Urinary tract infections in young febrile children. Pediatr
Infect Dis J 1997;16(1):11-7.

Hoberman A, Wald ER, Hickey RW, Baskin M, Charron M, Majd M, Kearney DH, Reynolds
EA, Ruley J, Janosky JE. Oral versus initial intravenous therapy for urinary tract
infections in young febrile children. Pediatrics 1999;104:79-86.

Copyright 2012 James K. Todd, M.D., All Rights Reserved