KIDNEY FOUNDATION FOR CHILDREN
SAVING YOUNG LIVES
LABORATORY DIAGNOSIS OF UTI
1. Routine urinalysis showing pyuria . > 5 WBCs /hpf in a centrifuged sample of urine
2. .Urine culture showing the growth of a single organism with 100,000 colonies /ml in a cleanly collected mid stream sample
WHEN TO SUSPECT UTI ?
UTI should be suspected in children with one or more of the following symptoms.
1 High fever without a focus
2. Fever with backache,abdominal or suprapubic pain
3. Fever with vomiting
4 .Dysuria,frequency,new onset nocturnal enuresis
5 .Lethargy ,malaise ,poor feeding in infants
6. Any sick neonate
7. Any child with known urological problem who has fever
UTI is the third commonest infection in children. Unlike acute gastroentiritis and pneumonias UTI is not self evident. UTI in young children may be a marker of an underlying urological probllem. Febrile UTI can scar the kidney. Repeated UTIs increase the risk of scarring. Scarred kidneys can can lead to hypertension and even chronic renal falure .Scarring secondary to vesico-ureteric reflux and UTI is an important cause of end stage renal disease in older children and young adults
DIAGNOSIS AND TREATMENT OF THE
SHOULD WE WAIT FOR THE CULTURE REPORT BEFORE TREATING UTI ?
No. Treatment should be started empirically based on clinical symptomatology and the presence of pyuria .Delay in instituting right therapy for more than 72 hours increases the risk of scarring. However, urine culture should be always sent before giving the first dose of the antibiotic
WHEN CAN ORAL ANTIBIOTICS BE SAFELY GIVEN ?
Children who are not at risk for renal damage or general sepsis.
1. Older children above 5 years of age
2. Absent or low grade fever
3. Lower urinary tract symptomatology
4. Not toxic or vomiting
5. Children on parenteral therpay who have become afebrile and urine pus cells have disappeared can be chaged to oral treatment if sensitivity on culture permits.
WHICH CHILDREN WITH UTI SHOULD RECEIVE PARENTERAL ANTIBIOTICS?
Children at high risk for renal damage or generalized sepsis should receive parenteral antibiotics
1 .Neonates and young infants
2. Children with high fever,vomiting and toxic look.
3. Children with known or suspected urological anomaly
4. Children with elevated creatinine.
COMMON ERRORS MADE IN THE DIAGNOSIS OF UTI
CHOICE OF ANTIBIOTICS
Parenteral - Third generation cephalosporins IV
Oral - According to known local prevalence
Current first line choice is usually cefixime
Duration of therapy is 10 days
MISINTERPRETATION OF PYURIA
UTI will invariably have pyuria but all pyuria is not due to UTI
.Several other causes of pyuria exist and should be considered especially when pyuria is mild,when the child is asymptomatic and urine culture is negative.
CAUSES OF PYURIA
HOW TO COLLECT THE RIGHT SAMPLE FOR URINE CULTURE
ERRORS IN URINE CULTURE
Urine culture positive with significant colony count is necessary to make a definitive diagnosis of UTI .However both false positive,false negative cultures are fairly common and occur due to errors in collecting the sample.
CAUSES OF FALSE NEGATIVE CULTURE
CAUSES OF FALSE POSITIVE CULTURE
Contaminated cultures may have mixed organisms,common skin commensals and may have growth < 100,000/ml..
WHAT SHOULD BE DONE FOR CHILDREN WITH SUSPECTED RENAL ANOMALY ?
1. The child should receive urinary prophylaxis after completion of the antibiotic course .Urinary prophylaxis should be continued till imaging studies re complete and further decisions can be taken.
2. USG kidneys,ureters and bladder in all cases
3.MCU after the infection is clear in selected children
a. children below 1 year of age
b. in older children with abnormal USG findings.
c .Children with recurrent UTI
4. DMSA scan after 4 to 6 months of the infection
WHEN TO SUSPECT AN UNDERLYING RENAL ANOMALY ?
1. Febrile UTI in a child below 1 year of age
2. Children with abnormalities on antenatal ultrasound
3 .Children especially boys with voiding complaints-poor stream of urine,interrupted stream of urine,dribbling,
4. Children with neurological problems myelomeningocoele, anorectal malformations
5.Children with recurrent UTI
6.Children with raised serum creatinine or hypertension or failure to thrive.