Urinary Tract Infection in Boys Less Than Five Years of Age: A General Pediatric Perspective
Hany M Nadi, Yasser A F Shalan, Hanan YA Al-Qatan , Saad Alotaibi
Department of Pediatrics, Farwania Hospital, Kuwait
Kuwait Medical Journal 2006, 38 (3): 220-225
Research appraisal
This research to examine the pattern of urinary tract infection (UTI) in boys < 5 years admitted to general pediatric wards and identifies the approach to imaging investigations. During the period from January 2002 through December 2002, 34 boys < 5 years of age were admitted to Farwania Hospital with UTI. Age at diagnosis, presenting features, urinal pathogens, acute phase reactants and imaging procedures were reviewed for these patients. All 34 patients in this study were less than one year. Fever was the most common presenting feature and was seen in 70.6% of patients. Pyuria was found in 77% , positive leukocyte esterase (LE) test in 85.7% and positive nitrite test in 45.7% of patients. Significant leukocytosis was found in 39.3%, high C-reactive protein (CRP) in 46.8% and high erythrocyte sedimentation rate (ESR) in 50% of children. Escherichia coli (E.coli) were the most common pathogen affecting 77.1% patients. Radiological investigations were recommended as follows: ultrasound scan (US) for all patients (94.2% did
conclusion
Unexplained fever in young boys should suggest UTI. Absence of fever does not exclude UTI, if other suggestive features exist particularly in the very young. UTI is commonly suggested by findings on urinalysis, on the other hand, negative urinalysis should not exclude the infection. Empiric antibiotics should cover gram-negative bacilli. Innovative strategies to ensure compliance to radiological investigations are needed.
Epidemiology
The epidemiology of UTIs in children varies with age. This age-dependent variation is of considerable clinical significance, since it defines important risk factors for UTI. The incidence of febrile UTIs is highest during infancy. In the age range from birth to 2 months, the diagnosis of acute pyelonephritis is usually made during evaluation for neonatal sepsis. The incidence of UTIs is about 4% in both male and female infants during the first year. However, most of the infections in male infants occur during the first 3 months. Numerous studies have shown that uncircumcised male infants have about 10 times as many UTIs as circumcised male infants, the infections occurring mainly during the first 3 months of life.
Winberg and colleagues suggested that the increased risk of infection is a consequence of colonization of the infant's GI tract and genitals in hospital maternity units by strains of E coli of nonmaternal origin, those to which the infant has no passive immunity. The increased risk of a UTI in the uncircumcised male infant appears to be secondary to adherence of E coli to the unkeratinized squamous mucosal surface of the prepuce. The circumcised prepuce is much less likely to harbor these potential uropathogens.
After the first year of life, the incidence of UTIs in boys drops to about 0.08%, while that in girls ranges from about 3% to 4% until 6 years. The higher incidence of UTIs in girls has been attributed to the relatively short female urethra. The incidence of first-time UTIs appears to be relatively low in children from 7 to 11 years, although good epidemiologic data to substantiate this are lacking. The annual incidence of UTIs has been given as 3 per 1000 girls and 0.2 per 1000 boys. The decreased incidence in this age group has been attributed to lengthening of the urethra in girls and the fact that most anatomic abnormalities predisposing to UTIs in boys would have been identified in earlier years.
There is an increase in the incidence of UTIs in adolescent girls, which is correlated with the frequency of vaginal intercourse. The theory underlying the hypothesis that sexual intercourse promotes UTIs is that vigorous and frequent sexual activity traumatizes the female urethra and forces bacteria into the bladder. Only a fraction of women appear to be at risk for intercourse-associated infection, presumably those already prone to UTIs. The risk is further increased with condom use. There is a 2- to 8-fold increase in risk of a first UTI with use of a lubricated condom or an unlubricated condom in combination with a spermicidal gel or cream.
Pathophysiology
Almost all UTIs are ascending in origin. Disturbance of the normal periurethral flora, which is part of the host defense against colonization by pathogenic bacteria, predisposes a person to a UTI. Bacteria of the periurethral flora also inhabit the distal urethra. Urine in the proximal urethra, urinary bladder, and other proximal sites in the urinary tract is normally sterile. Uropathogens must gain access to the urinary bladder and proliferate for infection to occur. Uropathogens in the distal urethra may gain access to the bladder because of turbulent urine flow during normal voiding or because of dysfunctional voiding. Successful urinary bladder colonization is unlikely unless bladder defense mechanisms are impaired because normal voiding usually results in an essentially complete washout of contaminating bacteria.
After birth, the periurethral area, including the distal urethra, becomes colonized with aerobic and anaerobic microorganisms that appear to function as a defense barrier against colonization by uropathogens. In early childhood, enterobacteria and enterococci are part of the normal periurethral flora. Escherichia coli is the dominant gram-negative species in young girls, whereas E coli and Proteus species predominate in boys. Children as old as about 5 years are predisposed to have UTIs, partly because of periurethral colonization by E coli, enterococci, and Proteus species. These potential uropathogens usually diminish in the first year of life and are rarely found in children older than 5 years. Studies of girls and women prone to UTI showed that periurethral colonization occurs with the specific bacterium that causes the next infection.
Hany M Nadi, Yasser A F Shalan, Hanan YA Al-Qatan , Saad Alotaibi
Department of Pediatrics, Farwania Hospital, Kuwait
Kuwait Medical Journal 2006, 38 (3): 220-225
Research appraisal
This research to examine the pattern of urinary tract infection (UTI) in boys < 5 years admitted to general pediatric wards and identifies the approach to imaging investigations. During the period from January 2002 through December 2002, 34 boys < 5 years of age were admitted to Farwania Hospital with UTI. Age at diagnosis, presenting features, urinal pathogens, acute phase reactants and imaging procedures were reviewed for these patients. All 34 patients in this study were less than one year. Fever was the most common presenting feature and was seen in 70.6% of patients. Pyuria was found in 77% , positive leukocyte esterase (LE) test in 85.7% and positive nitrite test in 45.7% of patients. Significant leukocytosis was found in 39.3%, high C-reactive protein (CRP) in 46.8% and high erythrocyte sedimentation rate (ESR) in 50% of children. Escherichia coli (E.coli) were the most common pathogen affecting 77.1% patients. Radiological investigations were recommended as follows: ultrasound scan (US) for all patients (94.2% did
conclusion
Unexplained fever in young boys should suggest UTI. Absence of fever does not exclude UTI, if other suggestive features exist particularly in the very young. UTI is commonly suggested by findings on urinalysis, on the other hand, negative urinalysis should not exclude the infection. Empiric antibiotics should cover gram-negative bacilli. Innovative strategies to ensure compliance to radiological investigations are needed.
Epidemiology
The epidemiology of UTIs in children varies with age. This age-dependent variation is of considerable clinical significance, since it defines important risk factors for UTI. The incidence of febrile UTIs is highest during infancy. In the age range from birth to 2 months, the diagnosis of acute pyelonephritis is usually made during evaluation for neonatal sepsis. The incidence of UTIs is about 4% in both male and female infants during the first year. However, most of the infections in male infants occur during the first 3 months. Numerous studies have shown that uncircumcised male infants have about 10 times as many UTIs as circumcised male infants, the infections occurring mainly during the first 3 months of life.
Winberg and colleagues suggested that the increased risk of infection is a consequence of colonization of the infant's GI tract and genitals in hospital maternity units by strains of E coli of nonmaternal origin, those to which the infant has no passive immunity. The increased risk of a UTI in the uncircumcised male infant appears to be secondary to adherence of E coli to the unkeratinized squamous mucosal surface of the prepuce. The circumcised prepuce is much less likely to harbor these potential uropathogens.
After the first year of life, the incidence of UTIs in boys drops to about 0.08%, while that in girls ranges from about 3% to 4% until 6 years. The higher incidence of UTIs in girls has been attributed to the relatively short female urethra. The incidence of first-time UTIs appears to be relatively low in children from 7 to 11 years, although good epidemiologic data to substantiate this are lacking. The annual incidence of UTIs has been given as 3 per 1000 girls and 0.2 per 1000 boys. The decreased incidence in this age group has been attributed to lengthening of the urethra in girls and the fact that most anatomic abnormalities predisposing to UTIs in boys would have been identified in earlier years.
There is an increase in the incidence of UTIs in adolescent girls, which is correlated with the frequency of vaginal intercourse. The theory underlying the hypothesis that sexual intercourse promotes UTIs is that vigorous and frequent sexual activity traumatizes the female urethra and forces bacteria into the bladder. Only a fraction of women appear to be at risk for intercourse-associated infection, presumably those already prone to UTIs. The risk is further increased with condom use. There is a 2- to 8-fold increase in risk of a first UTI with use of a lubricated condom or an unlubricated condom in combination with a spermicidal gel or cream.
Pathophysiology
Almost all UTIs are ascending in origin. Disturbance of the normal periurethral flora, which is part of the host defense against colonization by pathogenic bacteria, predisposes a person to a UTI. Bacteria of the periurethral flora also inhabit the distal urethra. Urine in the proximal urethra, urinary bladder, and other proximal sites in the urinary tract is normally sterile. Uropathogens must gain access to the urinary bladder and proliferate for infection to occur. Uropathogens in the distal urethra may gain access to the bladder because of turbulent urine flow during normal voiding or because of dysfunctional voiding. Successful urinary bladder colonization is unlikely unless bladder defense mechanisms are impaired because normal voiding usually results in an essentially complete washout of contaminating bacteria.
After birth, the periurethral area, including the distal urethra, becomes colonized with aerobic and anaerobic microorganisms that appear to function as a defense barrier against colonization by uropathogens. In early childhood, enterobacteria and enterococci are part of the normal periurethral flora. Escherichia coli is the dominant gram-negative species in young girls, whereas E coli and Proteus species predominate in boys. Children as old as about 5 years are predisposed to have UTIs, partly because of periurethral colonization by E coli, enterococci, and Proteus species. These potential uropathogens usually diminish in the first year of life and are rarely found in children older than 5 years. Studies of girls and women prone to UTI showed that periurethral colonization occurs with the specific bacterium that causes the next infection.