1. Pediatric Urinary Tract Infections
Dr.Fahad Gadi, MD
Pediatrics Demonstrator
King Abdulaziz University
Rabigh Medical School

2. Objectives Define Urinary Tract Infection (UTI)
List antibiotic treatment options for UTI
List the workup after a first febrile UTI
Be familiar with the rationale for using prophylactic antibiotics after the first febrile UTI

3. Pediatric UTIs and EBM
Up to 7% of girls and 2% of boys experience a symptomatic culture-proven UTI prior to 6 years of age.
Of febrile neonates, up to 7% have UTIs.
(See Fever without a source guidelines)
Most UTIs in children are from ascending bacteria
E. coli (60-80%), Proteus, Klebsiella, Enterococcus, and coag. neg. staph.

4. Epidemiology
The overall prevalence of UTI is approximately 5 percent in febrile infants but varies widely by race and sex.
Caucasian children had a two- to fourfold higher prevalence of UTI as compared to African-American children
Females have a two- to fourfold higher prevalence of UTI than do circumcised males
Caucasian females with a temperature of 39 ºC have a UTI prevalence of 16 percent

5. Approximate probability of urinary tract infection in febrile infants and young children by demographic group
Demographic group
Prevalence (pretest probability)
Odds
Circumcised boys >1 yr
<1 percent
.01 (1 in 100)
Circumcised boys <1 yr
2 percent
.02 (1 in 50)
Black girls
4 percent
.04 (1 in 25)
Uncircumcised boys <2 yr
8 percent
.09 (1 in 12)
White girls <2 yr
16 percent
.19 (1 in 5)

6. Definition of UTI on culture
Method of urine collection
Diagnostic threshold
Clean-catch in voiding girls
100,000 CFU per mL
10,000 – 100,000  repeat culture
Clean-catch in voiding boys
10,000 CFU per mL
Catheter
10,000 CFU
1,000 – 10,000  repeat culture
Suprapubic aspiration
Any colonies of GNRs
More than a few thousand GPCs

7. Symptoms Classic UTI symptoms in older children
Dysuria, frequency, urgency, small-volume voids, lower abdominal pain.
Infants with UTIs have nonspecific symptoms
Fever, irritability, vomiting, poor appetite

8. Neonatal hematuria?
Nope, it’s uric acid crystals

9. Evaluation
In children with a high likelihood of UTI, a urine culture is required.
In children with a low likelihood, a negative dipstick in a clear urine reduces the need for culture.
If the dipstick shows (+) LE and/or (+) Nitrites, send a urine culture.
The dipstick is not sufficient to diagnose UTI’s because false positives can occur.

10. Urine dipsticks
In a cohort study with an 18% baseline prevalence of UTI, negative LE and nitrates on dipstick had a negative predictive value of 96%.
NPV = True negative
_________________
True negative + false negative

11. Leukocyte Esterase and Nitrites
LE is produced from the breakdown of leukocytes. Not always indicative of infection
Vaginitis/vulvitis can lead to inflammation without infection  + LE
Nitrites are produced by bacteria that metabolize nitrates: E. coli, Klebsiella, Proteus (GNRs)
Much more predictive of UTI
GPCs do not produce nitrites

12. Blood cultures
Blood cultures are generally unnecessary in most children with UTI.
They are more frequently positive in children younger than two months whose urine grows Group B strep or Staph. Aureus.
In general, we’ll send febrile children less than two months old to the ER for emergent evaluation/labs.

13. Treatment of UTIs
The efficacy of oral regimens is as effective as parenteral regimens - this is great news for outpatient therapy 
If the child is not responding the empiric treatment within two days while awaiting culture results, repeat the urine culture and perform a renal ultrasound.

14. Antibiotic Choices
Trimethoprim-sulfamethoxizole is a good choice after two months of life
Other choices:
Amoxicillin – some resistance with E. coli
Cephalosporins: cefixime (Suprax), cefpodoxime (Vantin), cefprozil (Cefzil), loracarbef (Lorabid)
No cephalosporins cover enterococcus
Treat for 7-14 days. One day course not effective.

15. Further testing/work-up
After the UTI resolves, what type of workup should ensue?

16. Vesicoureteral Reflux and Treatment
Approximately 40% of children with febrile UTIs have VUR.
Approximately 8% of children with febrile UTIs demonstrate renal scarring when studied.
Treatment recommendations are made to stop the progression of VUR with medications/antibiotics and/or surgery.
No data/EBM demonstrate that treatment of VUR prevents renal scarring, hypertension and CKD

17. Antibiotic prophylaxis
Children with VUR are treated prophylactically with antibiotics to prevent potential renal scarring.
Nitrofurantoin or trimethoprim-sulfamethoxizole
Half the standard dose administered at bedtime
Family physicians would generally have a pediatric urologist involved to assist in making treatment decisions.

18. How long to continue Abx?
Although the evidence is not conclusive, it appears the risk of scarring diminishes with age.
Accordingly, some experts recommend cessation of prophylaxis after age 5 to 7 years, even if low-grade VUR persists.
In one study of 51 low-risk (no voiding abnormalities or renal scarring) older children (mean age 8.6 years) with grades I to IV VUR, cessation of prophylactic antibiotics resulted in no new renal scarring on annual DMSA

19. Indications to order radiologic studies
Children younger than 5 years of age with a febrile UTI
Girls younger than 3 years of age with a first UTI
Males of any age with a first UTI (PUV)
Children with recurrent UTI
Children with UTI who do not respond promptly to therapy

20. Studies to consider Renal Ultrasound
Will evaluate for perinephric abscess in patients not responding to antibiotics.
Can evaluate for hydronephrosis/hydroureter
Of note, dilation of the kidneys and ureters can easily be seen on routine anatomy scans during pregnancy.
Picking up vesicoureteral reflux while asymptomatic
Does this help or hurt? Staging of VUR, antibiotics, etc...

21. Hydronephrosis

22. Male with the findings below. Cause?

25. Studies to consider Voiding cystourethrogram – two techniques
One involves fluoroscopic contrast – more radiation but better delineation of anatomy for grading VUR
The other uses a radionuclide – less radiation and more sensitive than contrast

26. Normal VCUG

27. Vesicoureteral reflux (VUR)

28. Megaureter

29. Studies to consider
Renal scintigraphy using dimercaptosuccinic acid (DMSA)
Can detect scarring in the kidneys.
Renal cells take up the tracer.
Those cells damaged by pyelonephritis or scarring do not take up the tracer.
Management or followup of patients does not change in most cases.
Thus, not generally used for initial evaluation.

30. Scar in the superior and inferior pole of the right kidney

31. Myths Bathing in bubble baths causes UTIs
Wiping back-to-front causes UTIs
Cranberry juice helps UTIs – only proven to be of minimal benefit in adult women. No proven benefit to children

32. VUR Treatment
Children 6 years or older with unilateral grade III to IV reflux without renal scarring can be treated medically. If the reflux is bilateral and/or there is renal scarring, surgical treatment is recommended.
Children 6 years or older with grade V reflux should be treated surgically with or without evidence of renal scarring, as their reflux is unlikely to resolve spontaneously.
Surgery also should be considered if medical therapy fails either because of poor compliance, breakthrough infections on account of antibiotic resistance, or significant antibiotic side effects. Finally, consideration of patient and parent preference is important in the final decision.

33. Objectives Define Urinary Tract Infection (UTI)
>100,000 CFU in clean catch girls
>10,000 CFU clean catch guys
>10,000 catheter specimen
List antibiotic treatment options for UTI
Amoxicillin, Bactrim, Cephalosporins
List the workup after a first febrile UTI
Consider renal U/S and VCUG
Be familiar with the rationale for using prophylactic antibiotics after the first febrile UTI
Prevent renal complications/scarring/pyelonephritis