Urinary tract infections remain the most common bacterial infection in childhood.
Urinary tract infections (UTIs) remain the most common bacterial infection in childhood [
In healthy children, urine in the collecting system and urinary bladder is sterile. The urethra on the other hand is colonized with bacteria. Urinary malformation, urine stasis, and adherence of bacteria to the uroepithelial mucosa are the main predisposing factors for the development of UTI. Congenital obstructive uropathy is often associated with UTI. The pathogenesis of UTI in detrusor sphincter dyssynergia syndrome is due to infrequent bladder emptying and stasis. This later condition sometimes also referred to as dysfunctional voiding [
Most of the studies evaluating UTI in children are observational, hence conclusions from such studies are limited [
In males, it is more common during neonatal period and early infancy and it declines afterwards [
A multicenter study in 2007 revealed that the cumulative risk of UTI in children under age 6 years is 6.2% [
Asymptomatic bacteriuria occurs in 1% and 3% of infants and preschool age children, in about 1% of older children [
Signs and symptoms vary greatly by age of the patient becoming more specific as the child grows older. Even in the absence of specific signs, a UTI should be included in the differential diagnosis of high-grade fever. Asymptomatic bacteriuria is present in about 3% of preschool age children, as mentioned in the previous section. About a third of these patients will have some symptoms of urinary tract eventually.
In young infants, symptoms are usually nonspecific and may include lethargy, decreased feeding, increased sleep, vomiting, and decreased urinary output [
In younger children, presence of upper respiratory infections, otitis media, or gastroenteritis does not eliminate the possibility of a UTI [
In older children, fever is usually the presenting symptom of UTI. A fever of greater than 38°C without a source has a positive likelihood ratio of 3.6 and with temperatures greater than 39°C have a positive likelihood ratio of 4 [
Adolescent girls may have urethritis from an STD. Hence, for proper diagnosis, laboratory evaluation is mandatory [
The recurrence rate for UTI is 12% after a first time UTI [
Urine in the bladder is usually sterile; thus any bacteria growing in should be considered an infection. Pryles reviewed the existing pediatric data in 1960 defined UTI in children [
Unfortunately, oftentimes the culture will grow a bacterium that is obviously a contaminant, either from the skin or from other parts of the genital tract. Such culture often has multiple organisms and colony count less than 105. Thus, most investigators define a UTI as the presence of single organism in the urine combined with signs or symptoms of UTI in the patient [
The traditional cutoff for urine obtained by noninvasive collection methods (bag or clean catch) has been 105 CFU/mL [
When there are multiple organisms, or low colony count, there is a higher chance of contamination [
Culture of the urine remains the gold standard for diagnosing UTIs [
As children get older and become toilet trained, mid-stream clean catch sample of urine is commonly used [
Urine dipstick is helpful for rapid screening till the culture result comes back. The dipstick gives information about nitrites and leukocyte esterase (LE). Nitrites are generated from the breakdown of dietary nitrate by bacteria [
LE alone has a positive predictive value of about 35.8% meaning that it has a false-positive rate of about 64.7% [
Definition of pyuria is not clear in the literature. Multiple studies and a few meta-analyses [
When the child appears sick, a CBC, CRP, blood culture, and procalcitonin should be obtained to evaluate for sepsis. The first two do not have reliability in differentiating upper from lower urinary tract infection [
In infants younger than 8 weeks, lumbar puncture is still recommended as there is lack of evidence to omit this step. There is usually CSF pleocytosis, although meningitis and UTIs are rare together [
All males and females with well-documented UTIs should be imaged for the presence of urological anomalies associated with UTI. The extent of evaluation varies depending on the age of presentation with the first UTI and severity of the episode. The younger the child, the higher the likelihood of anatomical abnormality, hence all children younger than 2 years. of age with well-documented UTI should be evaluated with a renal ultrasound. Beyond 8 yrs of age, boys with UTIs still warrant a renal ultrasound. Girls with a first time simple UTI can likely be observed [
Renal ultrasound is helpful in delineating anatomic abnormalities [
A DMSA is a nuclear scan that is often used either to diagnose pyelonephritis or permanent renal scars [
All vesicoureteric reflux is diagnosed by VCUG. VCUG does not need to be performed for every febrile UTI. It should, however, be performed if renal ultrasound shows hydronephrosis or any other sign of VUR [
It requires catheterization. The radiation exposure can be reduced by performing a radionucleotide cytourethrogram but this study does not help detect anatomical abnormalities and only grades the reflux into mild–moderate and severe [
The goal of the acute treatment is to decrease morbidity, and to prevent long-term renal damage. Depending on patient’s clinical symptoms and tolerance, therapy can be oral or parenteral as they have both been found equally efficacious. If intravenous antibiotics are used, they can usually be changed to oral in 24 to 48 hours. Parenteral administration of an antimicrobial agent also should be considered when adherence to oral regimen is uncertain [
The usual antibiotic choices are cephalosporins, amoxicillin plus clavulanic acid, or trimethoprim sulfamethoxazole. It is also important to be aware local pathogens and antibiotic susceptibility [
Asymptomatic bacteriuria in infants and children should not be treated with antibiotics [
Dysfunctional voiding syndromes and constipation should be considered in young children and adolescents with UTI. Symptoms include recurrent UTI, constipation, encopresis, and day-time enuresis. Dysfunctional voiding if unrecognized and not managed properly could lead to reflux nephropathy. This later syndrome is associated with renal scars, hypertension, and chronic kidney disease. Children should be encouraged to void frequently and hydrate well. Children should have ready access to clean toilets when required and should not be expected to delay voiding [
In the recent years, the rule of vesicoureteric reflux in UTIs and the role of prophylactic antibiotics in preventing UTIs have been controversial. There have been a few trials in younger children that found no benefit of antibiotic prophylaxis [
VUR often undergoes spontaneous resolution. The time from first UTI to resolution of VUR is 6-7 yrs. Comparison of medical and surgical treatment of VUR is hard as different studies use various outcomes. Hodson et al. [
Infants and children with uncomplicated UTIs who do not undergo imaging investigations do not require follow up by a subspecialist. Infants and children who have recurrent UTI or abnormal imaging results should be assessed by a pediatric specialist. Assessment of infants and children with renal parenchymal defects should include height, weight, blood pressure, and routine testing for proteinuria. Infants and children with a minor, unilateral renal parenchymal defect do not need long-term followup unless they have recurrent UTI or family history or lifestyle risk factors for hypertension [
Infants and children who have bilateral renal abnormalities, impaired kidney function, raised blood pressure, and/or proteinuria should receive monitoring and appropriate management by a pediatric nephrologist to slow the progression of chronic kidney disease.
Infants and children who are asymptomatic following an episode of UTI should not routinely have their urine re-tested for infection. Asymptomatic bacteriuria is not an indication for followup [
Healthcare professionals should ensure that when a child or young person has been identified as having a suspected UTI, they and their parents are given information about the need for treatment, the importance of completing any course of treatment and advice about prevention and possible long-term management [
Parents should be made aware of the possibility of a UTI recurring and understand the need to be vigilant and to seek prompt treatment from a healthcare professional for any suspected reinfection.
Parents should be educated about healthy voiding and stooling habits as means of preventing UTIs.
Urinary tract infections are common in children. If recurrent or severe, they do have the potential to cause renal scarring. All younger infants with fever of unexplained origin should have their urine tested and older children with symptoms should also be evaluated for UTIs. The gold standard for testing for UTI is suprapubic aspiration but a urinalysis and a urine culture (catheterized/clean catch depending on age) is acceptable. Once diagnosed, prompt and appropriate antibiotic treatment can prevent long-term complications and scarring. All younger infants with UTI and older children with complicated UTI should get a renal ultrasound. This should be followed by VCUG only if there is evidence of reflux on ultrasound. A DMSA scan can help evaluate renal scarring. Prophylactic antibiotics are reserved for recurrent UTIs and do not seem to benefit patients with low-grade VUR. Preventative measures include treating constipation and voiding dysfunction.