28 Ö. Aydogdu and C. Radmayr

TABLE 3.2.  Interpretation of the urine culture results in the diagnosis of UTIs in children.

Taken from EAU guidelines, update March 2009

•Urine cultures in infants and children smaller than 6 months of age, without another focus of infection, show an incidence of UTI in approximately 8% with an axillary temperature of greater than 38.3°C.20-23, 25

•As aforementioned concentration of bacteriuria in urine and thus the criteria of UTI in children mainly depend on the method of urine collection (Table 3.2). Diuresis, method of the storage and transport of the urine are also critical.

3.7  Imaging Studies

Ultrasoundscan(USG),voidingcystourethrography(VCUG), and DMSA are the three main imaging options for the investigation of UTI in children.18, 26-29 According to some recent studies imaging work-ups for children with a first uncomplicated UTI may not improve the patient management.27,28

However other studies advocate that, although only minority of children with a UTI has an underlying urological disorder, morbidity can be disruptive for diseased children. Therefore after a maximum of two UTI episodes in girls and one episode in boys, imaging studies should be undertaken.18, 27

•Use of all three renal imaging techniques is neither realistic nor practical.

•A gold standard imaging technique should be painless, non-invasive, safe, reliable enough to detect any structural

anomaly and cost-effective.There is not any present radiological technique, fulfilling all these requirements.

•Urinary USG; for the detection of congenital abnormalities, obstruction, and renal scarring.

•VCUG; for the identification of VUR.

•DMSA; for the determination of renal scarring.

3.8  Ultrasound Scan (USG)

1.Safe, rapid, cost-effective and high accuracy in identifying the anatomy and size of the renal parenchyma and collecting system.27, 29

2.Subjective and provides no information on renal function.

3.USG alone is not enough to rule out VUR. A child with high grade reflux in VCUG may have a totally normal urinary USG.27, 28

4.Bladder USG can be used to determine the post void residual urine volume.

3.9  Voiding Cystourethrography (VCUG)

1.Urine sterility is mandatory to perform VCUG.

2.It is considered to be essential in the evaluation of UTIs in children less than 1 year of age.25, 28

3.It is mandatory in the assessment of febrile UTIs in children.

4.Up to 23% of children with febrile UTI and normal USG may reveal VUR in VCUG.28

5.Disadvantages include the risk of infection, invasive and radiation exposure.27, 28

6.Fluoroscopic VCUG may be used instead of conventional VCUG in order to minimize the radiation exposure.

7.Timing of VCUG in the investigation of UTI remains controversial. In some studies it was highlighted that VCUG should be performed 4–6 weeks after the acute infection.28

8.According to some recent studiesVCUG can be performed as long as the child is free of infection.27, 28

30 Ö. Aydogdu and C. Radmayr

3.10  Dimercapto-Succinic Acid Scan (DMSA)

1.DMSA scan rightly remains the gold standard in the prediction of renal scarring. In a study its specificity and sensitivity for renal scarring were found as 100% and 80% respectively.27

2.This technique is helpful in determining functional renal mass and cortical scarring.

3.A star shaped defect in the renal parenchyma may indicate an acute episode of pyelonephritis.

4.A focal defect in the renal cortex often indicates a chronic lesion.

5.DMSA scan may help to differentiate between the good and the bad prognosis of UTIs in children.18, 27

3.11  Treatment

Management of a child with possible UTI is critical due to potential irreversible morbidities which can be avoided with proper treatment. Figure 3.1 summarizes the management of UTIs in children.

The main goal of the treatment in the acute period is to eliminate the symptoms and get rid of the bacteria. In the long term the treatment should aim firstly to preserve renal function by preventing possible renal scarring, prevent recurrent UTIs and correct underlying urological disorders.14, 16, 19

1.Antimicrobial treatment should be initiated on an empirical basis and should be adjusted according to the urine culture results.

2.The child should be reevaluated with a repeat urine culture and urinary USG if clinical improvement does not occur within two days.

3.If UTI is considered to be simple, oral rehydration and oral antibiotics on an outpatient basis may be sufficient. Oral empirical treatment with trimethoprim (TMP), cotrimoxazole (TMP plus sulphamethoxazole), cephalosporin or amoxycillin/clavulanate is recommended. The

Persistent reflux

Evaluation for urologic intervention

FIGURE 3.1.  Management of UTIs in children.

preferred oral medication may differ due to the local resistance pattern.

4.Although there can be some variations due to different regions, the resistance rates in UTIs caused by E. coli are highest for ampicillin (39–45%) and co-trimoxazole (14– 31%) and lowest for nitrofurantoin (1.8–16%) and fluoroquinolones (0.7–10%).

5.The duration of treatment in case of simple UTI should be 5–7 days.

6.If the child is not able to tolerate oral fluid intake or the response to oral antibiotics is poor, intravenous hydration and antibiotics should be administered in the hospital.

7.Preferred intravenous antibiotic in case of severe UTI should be a third generation cephalosporin. If a gram positive bacterium is suspected, it is better to use aminoglycosides (serum levels should be monitored) in combination with ampicillin or amoxycillin/clavulanate.