Urinary Tract Infections in Children

Symptoms
Examination
Pathophysiology
Pathogens
Treatment
Evaluation (RUS, VCUG, Renal Scan)
Reflux
Prophylaxis
Surveillance
Referral

Symptoms

Have a high index of suspicion if there is...

Fever without localizing signs
Lethargy, nausea, vomiting, anorexia, or feeding problems
Failure to thrive
Dysuria, Frequency
Abdominal pain, costovertebral angle tenderness
"Strong smelling urine"
Pyuria
Family history of reflux or chronic pyelonephritis
Constipation
Eneuresis
Hypertension
Renal Failure
Neurogenic bladder (e.g., myelomeningicele)
Phimosis
Poor voiding habits (infrequent or incomplete voiding)
Perineal hygiene problems; pinworm infestation
Sexual intercourse; sexual abuse

By age:

Symptoms of UTI by age category
Newborns	Infants (age 2-5 years)	Older than 5 years
Jaundice	Diarrhea	Abdominal pain
Failure to thrive	Failure to thrive	Frequency
Fever	Fever	Fever
Vomiting	Vomiting	Vomiting
Hypothermia	Strong smelling urine	Strong smelling urine
Sepsis		Dysuria
		Urgency
		Eneuresis

Examination

For diagnosis, a good specimen is necessary: catheterized, suprapubic aspiration, or clean catch midstream urine for U/A and culture.

More than 100,000 colonies in a clean catch specimen are significant
More than 1000 colonies in a catheterized specimen.

Other items relevant to UTI exam:

Blood culture (and sometimes LP) in toxic infants
CBC, BUN, Cr if pyelonephritis is suspected
Urinalysis (U/A) for:

nitrite
leukocyte esterase
blood
pyuria

Note that a Gram stain combined with leukocyte esterase has 100% sensitivity (gets all true positives plus some false positives) and 100% negative predictive value (negative gram stain and negative leukocyte esterase rules out possibility of UTI).

Pathophysiology

Birth to 12 weeks of age	Hematogenous spread (vs. secondary bacteremia)
Older than 12 weeks of age	Ascending infection by GI pathogens

Pathogens

E. coli (most common)
Klebsiella
Proteus (produces alkaline urine)
Enterococcus
Pseudomonas
Enterobacter
Staph. saprophyticus and aureus
Group B Streptococcus

Treatment

Toxic child: IV ampicillin plus cefotaxime/ceftriaxone/gentamycin
PO: amoxacillin or TMP/SMX until sensitivities are known
Adjust antibiotics after sensitivities come back; may change to po after afebrile for 24 hours
Treat 10 days total
Review hygiene, treat constipation, d/c bubble baths
Consider circumcision

Evaluation

Usually abdominal ultrasound plus VCUG

For all males whenever they are infected
For all infants infected during the first year of life
For all females less than five with

evidence of pyelonephritis
recurrent UTIs

Ultrasound of kidneys and bladder	To detect congenital anomalies and hydronephrosis. Does not assess function.
Voiding Cystourethrogram (VCUG)	To detect reflux, posterior urethral valves. Note that an isotope VCUG has lower radiation dose, but does not define urethral or bladder wall anomalies. If the patient is stable, wait 3 weeks to do studies to allow post-infection bladder irritability and reflux to resolve.
Renal (DMSA) Scan	If you suspect pyelonephritis, or if reflux is seen on VCUG, consider a DMSA (dimercaptosuccinic acid labelled with Tc99m) scan to detect renal parenchymal changes of pyelonephritis and scarring.
Mag III Scan	To evaluate hydronephrosis without reflux (for example, UP obstruction).
Intraveous pyelogram (IVP)	Rarely used anymore.

Reflux (vesiculo-ureteral)

Present in 30-50% of children diagnosed with UTIs
Grades I-III usually resolve spontaneously within five years.
Grade IV and V: only 40% resolve spontaneously.

Prophylaxis

When recurrences occur more than four times in one year.
When reflux is present (until it resolves)
After acute UTI and until VCUG is performed
In a less than 2 year old child (for 6-12 months)

Less than 6 weeks: cephalosporin such as cephalexin (Keflex)
Less than 1 year: TMP/SMX
More than 1 year: Nitrofurantoin

TMP/SMX and Nitrofurantoin are given at 1/3 of the daily dose given at bedtime for 9-12 months.

Surveillance

For sick children (or maybe all children with UTIs) culture after 48 hours of treatment to verify that the urine is sterile.
Culture 4-7 days off treatment
Reculture at one month and then every 3 months for one year (can use a bagged specimen in circumcized males if properly collected).
Repeat the DMSA scan after 6-12 months if the first scan was abnormal.

Referral

Obstructive uropathy (posterior urethral valves, ureteropelvic junction obstruction, ureterovescicular junction obstruction, ureterocele, duplicated collecting system).
Renal scarring
Voiding problems
Anatomic abnormalities

This page adapted from a clinic seminar written by Dr. Susan DeMuth, Arlington Hospital, VA.

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Last modification: January 10, 2000