Introduction
      •  Urinary tract infections (UTI) is common in the pediatric 
         age  group.  Early  recognition  and  prompt  treatment  of 
         UTI are important to prevent progression of infection to 
         pyelonephritis or urosepsis and to avoid late sequelae 
         such as renal scarring or renal failure. 
      •  Infants  and  young  children  with  UTI  may  present  with 
         few specific symptoms. Older pediatric patients are more 
         likely to have symptoms and findings attributable to an 
         infection of the urinary tract. Differentiating cystitis from 
         pyelonephritis  in  the  pediatric  patient  is  not  always 
         possible, although children who appear ill or who present 
         with fever should be presumed to have pyelonephritis if 
         they have evidence of UTI. 
   Pathophysiology
 • UTI  generally  begins  in  the  bladder  due  to  ascending 
   infection from perineal contaminants, usually bowel flora 
   such  as  Escherichia  coli.  In  neonates,  infection  of  the 
   urinary  tract  is  assumed  to  be  due  to  hematogenous 
   rather  than  ascending  infection.  This  etiology  may 
   explain the nonspecific symptoms associated with UTI in 
   these patients. 
 • After the neonatal period, bacteremia is not the usual 
   cause of UTI. The bladder is the initial primary locus of 
   infection  with  ascending  disease  to  the  kidneys. 
   Bacteremia  may  then  appear  as  potential  sequelae. 
   Bacterial invasion of the bladder with overt UTI is more 
   likely  to  occur  if  urinary  stasis  or  low  flow  conditions 
   exist.  This  is  triggered  by  infrequent  or  incomplete 
   voiding, reflux, or other urinary tract abnormalities. 
    Pathophysiology/2
   •
   Even  in  the  absence  of  urinary  tract 
   abnormalities,    cystitis   may     lead     to 
   vesicoureteral reflux, and it may worsen a pre-
   existing  reflux.  Untreated  reflux  causes 
   pyelonephritis.    Chronic      or    recurrent 
   pyelonephritis  results  in  renal  damage  and 
   scarring  that  may  progress  to  chronic  renal 
   failure. 
   •
   Prevalence varies based on age and sex
    Clinical Course
    • Generalized  bacteremia  or  sepsis  may  follow 
      UTI.  Approximately  30%  of  1-  to  3-month-old 
      infants with UTI are at risk of developing sepsis. 
      The risk drops to approximately 5% in patients 
      older than 3 months.
    • If left untreated, simple cystitis may progress to 
      pyelonephritis.  More  severe  cases  have  the 
      potential for kidney damage, which may lead to 
      hypertension or renal insufficiency.
    • Approximately    5-10%    of   children   with 
      symptomatic  UTI  and  fever  develop  renal 
      scarring.
  Frequency of UTI
  • UTI is more frequent in females than males at all 
   ages with the exception of the neonatal period, 
   during which UTI may be the cause of an 
   overwhelming septic syndrome in male infants 
   younger than 2 months.
  • Uncircumcised males have a higher incidence 
   than circumcised males. Uncircumcised male 
   infants have a higher incidence of UTI than 
   female infants.