All pediatric patients with a well-documented urinary tract infection (UTI) require urologic evaluation.
What constitutes a well-documented UTI? One can minimize potential errors by the following:
A. OBTAINING THE SPECIMEN
1. Bag Urines
Bag urines are easy and the least invasive but also the LEAST reliable. Reliability may be improved:
- if the patient is symptomatic (e.g., fever, discomfort on voiding or blood in urine),
- if early morning urines are used (these usually have the highest counts),
- if the spun urine specimen is examined under the microscope at the time of collection in addition to being submitted for culture, and
- if the specimen is cultured immediately.
2. Clean Catch
The clean catch is reasonably accurate after the age of three years but again is also best checked by spinning a sample down and viewing it under the microscope at the time of collection. This is better than relying simply on stick testing. Lab-stick testing to diagnose a UTI is often negative when the urine is infected.
3. Catheter or Feeding Tube Collection
Catheter or better yet, FEEDING TUBE COLLECTION (with Xylocaine jelly lubrication) after cleansing the genitalia and discarding the first few drops of the catheter specimen is a more accurate method of detecting a UTI. Positive bag urines in asymptomatic patients, especially girls and uncircumcised boys, should always be rechecked to confirm a UTI before investigation.
4. Suprapubic Bladder Aspiration
Suprapubic bladder aspiration is useful and most accurate in neonates to confirm a urinary tract infection.
B. INVESTIGATING AFTER A WELL DOCUMENTED UTI
Whether male or female, only one well-documented urinary tract infection is required before proceeding with investigation. The following initial studies are recommended:
1. Renal and Pelvic Sonogram
2. VCUG (Voiding Cystourethrogram)
Ultrasound is a good screening tool to detect hydronephrosis, cysts and mass anomalies.
It is IMPORTANT to make sure that the VCUG is performed by the radiologist and not just the technician. In this way both the storage and voiding phases can be viewed under fluoroscopy, as reflux may be seen in only one of these phases and then fleetingly. In addition, examination of the lumbosacral spine may indicate neurogenic causes for voiding dysfunction. The urethra is examined in males to exclude valves. Cystoscopy is rarely, if ever, required in the evaluation of a UTI.
EXAMPLES TO AMPLIFY IMPORTANCE OF EARLY EVALUATION OF UTI
A 16 year old girl presented to the emergency room with hypertensive encephalopathy secondary to end-stage renal disease. She had had one documented UTI as an infant and her physicians were waiting for the next infection to occur before considering investigation. However, she remained “asymptomatic” until she presented with the effects of end-stage reflux nephropathy. She has since undergone a living related renal transplant.
A 12 year old boy with gross bilateral reflux and decreased renal function recently presented with his first symptom ever, an episode of gross hematuria and an infection. There had been no symptoms referable to the urinary system at any time previously and in particular no previous UTIs.
It is a myth to believe that a patient will readily become symptomatic if there is an underlying urologic problem or that if there is an underlying problem, the patient will necessarily become reinfected. It is not uncommon for patients to have gross disease yet be asymptomatic.
Early evaluation after the first well-documented infection may allow treatment in some before progression of the disease.