178. Save Your Kidneys
Diagnosis of Urinary Tract Infection
Investigations performed in children with urinary tract infections include:
1. Basic investigations in urinary tract infection
- Screening tests for UTI: Urine microscopy or dipstick tests. Further
details are discussed in Chapter 18.
- Definitive diagnostic test for UTI: Urine culture and sensitivity (Urine
CS) test for confirmation of diagnosis, identification of the specific bacteria causing infection and selection of the most appropriate
antibiotic for treatment.
- Blood tests: Hemoglobin, total and differential white cell count, blood
urea, serum creatinine, blood sugar and C reactive protein.
2. Investigations for diagnosis of risk factors of urinary tract
infection
- Radiological tests to detect underlying abnormalities: Ultrasound of
kidney and urinary bladder (KUB), X-rays of the abdomen, Voiding
Cystourethrogram (VCUG), CT scan or MRI of the abdomen and
Intravenous Urography (IVU).
- Tests to detect scarring of kidney: A dimercaptosuccinic acid
(DMSA) kidney scan is the best method for detecting kidney scarring.
DMSA scan should be done preferably 3 to 6 months after an
episode of UTI.
- Urodynamic studies to assess bladder function.
What is a voiding cystourethrogram? When and how is it
done?
- Voiding cystourethrogram or VCUG (previously known as
Micturating cystourethrogram or MCU) is a very important
diagnostic X-ray test for children with urinary tract infection and
vesicoureteral reflux (VUR). VCUG test is the gold standard for
the diagnosis of vesicoureteral reflux and its severity (grading), and
detection of abnormalities of the urinary bladder and urethra. It
should be done for every child below 2 years after the first episode
of UTI.
- VCUG should be done after treating UTI, usually after the first week
of diagnosis.
- In this test the urinary bladder is filled to its capacity with contrast
(radio opaque iodine containing dye fluid which can be seen on X-
ray films) through a catheter under strict aseptic precautions and
usually under antibiotic cover.
- A series of X-ray images are taken before and at timed intervals
during voiding. This test provides a comprehensive view of the
structure and the function of the bladder and urethra.
- VCUG can detect urine flow from the bladder backwards into the
ureters or kidneys, known as vesicoureteral reflux.
- VCUG is also used to detect the presence of a posterior urethral
valve in male infants.
Common symptoms of UTI in children are recurrent
fever, poor weight gain and urinary problems.