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Pediatric Urinary Tract Infection and Reflux
JONATHAN H. ROSS, M.D., and ROBERT KAY, M.D.
Cleveland Clinic Foundation
Cleveland, Ohio
Urinary tract infections in children are sometimes associated with vesicoureteral
reflux, which can lead to renal scarring if it remains unrecognized. Since the risk of
renal scarring is greatest in infants, any child who presents with a urinary tract
infection prior to toilet training should be evaluated for the presence of reflux.
Children who may be lost to follow-up and those who have recurrent urinary tract
infections should also be evaluated. The preferred method for evaluation of urinary
reflux is a voiding cystourethrogram. Documented reflux is initially treated with
prophylactic antibiotics. Patients who have breakthrough infections on prophylaxis,
develop new renal scarring, have high-grade reflux or cannot comply with long-term
antibiotic prophylaxis should be considered for surgical correction. The preferred
method of surgery is ureteral reimplantation. A newer method involves injection of
the bladder trigone with collagen.
Urinary tract infections in children are a significant source of morbidity, particularly
when associated with anatomic abnormalities.1 Vesicoureteral reflux is the most
commonly associated abnormality, and reflux nephropathy is an important cause of
end-stage renal disease in children and adolescents.2 However, when reflux is
recognized early and managed appropriately, renal insufficiency is rare. Some
children who present with an apparently uncomplicated first urinary tract infection
turn out to have significant reflux. Subclinical infections can sometimes lead to
severe bilateral renal scarring. Therefore, even a single documented urinary tract
infection in a child must be taken seriously.
Diagnosis
Children with urinary tract infections do not always present with symptoms such as
frequency, dysuria or flank pain. Infants may present with fever and irritability or
other subtle symptoms, such as lethargy. Older children may also have nonspecific
symptoms, such as abdominal pain or unexplained fever. A urinalysis should be
obtained in a child with unexplained fever or symptoms that suggest a urinary tract
infection. In young children with urinary tract infections, urinalysis may be negative
in 20 percent of cases. Barnaff and colleagues3 recommend a urine culture for all
male patients under six months of age and all female patients under two years of
age who have a temperature of 39°C (102.2°F) or higher. Because a documented
infection may warrant a thorough radiographic evaluation, empiric treatment on the
basis of symptoms or urinalysis alone should be avoided.
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FIGURE 1. (A) Acute pyelonephritis demonstrated in a
technetium-99m dimercaptosuccinic acid (DMSA) renal scan.
Note the photopenic area with preservation of renal contour
(arrow). (B) Follow-up scan demonstrating cortical defect
consistent with subsequent renal scar formation (arrow).
While the most reliable method of obtaining urine for a culture is suprapubic
aspiration, this procedure often causes anxiety in the child, the parent and the
physician. Urine specimens may therefore be obtained by placing a plastic bag over
the perineum of infants, and by obtaining a voided specimen in older children.
Because "bagged" and voided specimens may be contaminated, results must be
interpreted in conjunction with the urinalysis and the clinical setting. Pyuria and/or
classic symptoms support the diagnosis of a urinary tract infection, whereas a
positive culture in a child with a normal urinalysis and/or atypical symptoms may
represent contamination. In patients whose diagnosis is complicated, and when the
uncertainty of contamination must be avoided, a catheterized or suprapubic
specimen can be obtained. Because catheterization may introduce bacteria into the
bladder, a single dose of oral antibiotic should be given to prevent iatrogenic
infection.
While the presence or absence of a true urinary tract infection is occasionally difficult
to determine, the distinction between cystitis and pyelonephritis is even more
problematic. No clinical findings (such as fever or flank pain) and no laboratory
studies (such as erythrocyte sedimentation rate or white blood cell count) are
accurate in distinguishing pyelonephritis from cystitis.4 Fortunately, this distinction is
rarely crucial. The management of the child is dictated by the clinical severity of the
illness, rather than by the specific site of infection in the urinary tract. Furthermore,
since the risk of reflux is similar in all patients with a urinary tract infection, the
distinction between cystitis and pyelonephritis is not important in guiding the need
for radiographic evaluation.
In rare circumstances, when distinguishing the diagnosis of pyelonephritis from some
other infection is important, a technetium-99m dimercaptosuccinic acid (DMSA) renal
flow scan is the best study to obtain.5 Patients with a normal scan during an acute
infection do not have pyelonephritis and will not develop scarring. However, an area
of photopenia on a DMSA scan identifies a region of pyelonephritis that is at risk for
eventual scar formation (Figure 1). Because this test is invasive, expensive, exposes
the child to radiation and is unlikely to alter the management of the infection, it is
not used in the routine evaluation of children with urinary tract infections.
Evaluation
The most significant anomaly associated with urinary tract infections in children is
vesicoureteral reflux, which occurs in 30 to 50 percent of these patients.6 Despite
the high rate of association, no randomized prospective studies demonstrate the
benefit of screening these patients for anomalies.7 However, there is no doubt that
vesicoureteral reflux is associated with renal scarring, in part because it allows lower
tract infections to ascend, resulting in pyelonephritis.5
Because of the risk of renal scarring, any child who has a
single urinary tract infection before toilet training has
begun may benefit from reflux screening.
Since antibiotic prophylaxis can prevent recurrent urinary tract infections, it seems
prudent to screen children with urinary tract infections who are at risk for renal
scarring, such as children with recurrent urinary tract infections. Since children are at
greatest risk for renal scarring in the first few years of life, reflux screening is
recommended for any child who has a single urinary tract infection before toilet
training has begun. Older children who receive consistent medical care (in whom a
pattern of recurrent urinary tract infections would not be missed) may not need to be
screened following a single infection. An alternative to more invasive screening might
be renal ultrasonography. Although ultrasonography is a poor screening test for
reflux, missed reflux may be of little concern in an older child with a single infection
and normal results on renal ultrasound examination.
When a child is screened for reflux, the appropriate test to obtain is a cystogram. A
cystogram performed by an experienced pediatric radiologist is well-tolerated by
most children. Although renal ultrasound examinations are less invasive, they are
normal in 50 to 75 percent of patients with reflux and, therefore, are ineffective for
screening.8 A DMSA renal scan is the best study for detecting renal scarring and
might therefore identify patients at particular risk for reflux. Unfortunately, a renal
scan will not detect reflux in children who have not yet developed scarring, and these
are the very ones who might benefit most from antibiotic prophylaxis.
Obtaining a cystogram in a patient with a urinary tract infection should be delayed
for at least 48 hours after initiating antibiotic therapy so as not to induce bacteremia
by instrumenting the urinary tract. It is not necessary to delay the cystogram beyond
this point. Concern that obtaining a cystogram too soon after a urinary tract infection
may result in a false-positive study is ill-founded. Even children who have reflux only
when they have cystitis have a significant problem, since reflux causes scarring by
allowing cystitis to ascend.5
FIGURE 2. Voiding cystourethrogram revealing bilateral grade 3
reflux into small, scarred kidneys.
A renal ultrasound examination may also be obtained to rule out obstructive
uropathy in children. An ultrasound examination can detect gross renal scarring or
marked asymmetry of renal size in patients with vesicoureteral reflux. A DMSA renal
scan is the best method for detecting renal scarring.9
Two types of cystogram are available. A standard voiding cystourethrogram (VCUG)
is obtained by instilling radiopaque contrast medium into the bladder and imaging
the bladder and renal fossae during filling and voiding (Figure 2). The severity of
vesicoureteral reflux is graded on a scale of 1 to 5, depending on the degree of
distention of the collecting system.
A nuclear cystogram can be obtained by instilling a radionuclide agent into the
bladder and imaging with a gamma camera. Nuclear cystography is at least as
sensitive for the detection of reflux as a standard VCUG and exposes the child to less
radiation.10 However, grading of reflux is less precise, and associated bladder
abnormalities cannot be detected with nuclear cystography. Therefore, a VCUG is
preferred as the initial study in the evaluation of a child with a urinary tract infection.
Nuclear cystography is used in follow-up of patients with vesicoureteral reflux who
are on an observation protocol. Vesicoureteral reflux is present in one third of
siblings of patients with reflux, and in two thirds of the children of patients with
reflux.11,12 Nuclear cystography may be employed for screening these children as
well.
Treatment
Because urinary tract infections are usually caused by gram-negative rods,
particularly Escherichia coli, any oral antibiotic with good gram-negative coverage is
a reasonable choice for treatment. Trimethoprim/sulfamethoxazole (Bactrim,
Spectra) offers good coverage and is inexpensive. It is given in suspension form in a
dosage of 4 mg trimethoprim per kg twice daily. Other commonly used antibiotics
include amoxicillin, in a dosage of 10 mg per kg three times daily, and nitrofurantoin
(Furadantin, Macrodantin, Macrobid), in a dosage of 2.5 mg per kg three times daily.
Cephalosporins may be indicated if infection with a more resistant organism is
suspected. Ciprofloxacin (Cipro) is not approved for use in children. However,
carbenicillin is available in an oral form for treating uncomplicated cystitis that is
caused by susceptible strains of Pseudomonas.
Children who require hospitalization should be placed on broad-spectrum intravenous
antibiotics pending the results of the urine culture. Because most communityacquired urinary tract infections are caused by gram-negative bacilli, coverage
should include an aminoglycoside, a cephalosporin or a broad-spectrum penicillin
derivative. Coverage may need to be broader in children who have recently been
hospitalized or who have had recent instrumentation or recurrent infections, since
they may be infected with gram-positive organisms such as Enterococcus or
coagulase-negative Staphylococcus. A urine gram-stain may be helpful in the initial
selection of antibiotics. An algorithm showing the evaluation and management of a
child with a urinary tract infection is presented in Figure 3.
Management of Urinary Tract Infection
Management of Vesicoureteral Reflux
Reflux resolves spontaneously in some patients. It is more likely to resolve if it is
low-grade, unilateral and not associated with anomalies. The grade of reflux is the
most important factor. Over several years of observation, reflux resolves in
approximately 80 percent of patients with grade 1 or grade 2 reflux, 50 percent of
patients with grade 3 reflux and 25 percent of patients with grade 4 reflux.13
Because of this tendency to resolve, most patients with reflux are initially treated on
an observation protocol.
A voiding cystourethrogram is preferred as the initial
study in the evaluation of a child with a urinary tract
infection.
The current management of reflux is based on direct and indirect scientific data, as
well as a traditional standard of care. With this in mind, the American Urological
Association recently developed clinical practice guidelines for the management of
reflux.14 Because renal scarring usually occurs only with the reflux of infected urine,
the prevention of urinary tract infections in children with reflux is essential, and the
mainstay of medical management is antibiotic prophylaxis. The most frequently used
agents are nitrofurantoin, in a dosage of 1 to 2 mg per kg once daily, and
trimethoprim/sulfamethoxazole, in a dosage of 2 to 4 mg trimethoprim per kg once
daily.
In patients under observation, periodic urine cultures should be obtained
(approximately every three months) to detect asymptomatic bacteriuria. Follow-up
cystograms are obtained annually, and prophylaxis is discontinued when reflux
resolves. Upper tract studies are obtained periodically as dictated by the patient's
clinical course. Bladder instability and constipation can predispose a child to urinary
tract infections and exacerbate reflux.15-20 The presence of these symptoms should
be actively determined and promptly treated.
Any patient under observation who develops a break-through urinary tract infection
or new renal scarring should undergo surgical correction of reflux. Surgery is also
appropriate in patients who cannot comply with close follow-up and long-term
antibiotic prophylaxis. This includes patients who wish to avoid repeat cystograms
and office visits. Patients with high-grade reflux may be considered for immediate
surgical intervention.
The standard operation for vesicoureteral reflux is ureteral reimplantation, which is
successful in 95 percent of cases.21 Although antireflux surgery effectively reduces
the risk of pyelonephritis, approximately one third of the children will continue to
have cystitis.21
The subtrigonal injection of collagen is a relatively new alternative treatment for
vesicoureteral reflux. This technique is performed as an outpatient cystoscopic
procedure under a brief general anesthetic. It involves significantly less morbidity
than the standard operation but is successful in only 65 to 70 percent of cases.22,23
The long-term efficacy of collagen injection has not yet been determined.
Recurrent Urinary Tract Infections
Some children without a discernable anatomic anomaly develop recurrent urinary
tract infections. Many of these children present after toilet training, when normal
spontaneous voiding is prevented by social constraints. The risk of renal scarring in
these patients is low, but not absent. Some of these children have symptoms of
bladder instability, such as urge incontinence or squatting behavior, in the absence
of an infection. Bladder instability may be improved by placing the child on a timed
voiding schedule of once every three hours. If behavioral approaches fail, voiding
symptoms often respond to anticholinergic agents such as oxybutynin (Ditropan), in
a dosage of 0.15 mg per kg three times daily. Even when the symptoms are subtle
and not in and of themselves troublesome, the recurrent infections can be prevented
or reduced in frequency by employing anticholinergic therapy in conjunction with
antibiotic prophylaxis. Constipation can also predispose to bladder instability and
recurrent urinary tract infections and should therefore be aggressively
managed.19,20
The prevention of urinary tract infections in children
with reflux is essential, and the mainstay of medical
management is antibiotic prophylaxis.
Even an anatomically and functionally normal urinary tract may be predisposed to
recurrent infections. Certain host factors may play a role, such as antigen expression
on the bladder epithelium.24 However, there is no specific therapy for these host
factors, so children with frequent infections are managed with antibiotic prophylaxis
administered in the same fashion as in patients with vesicoureteral reflux. However,
in the absence of reflux, upper tract monitoring and routine urine cultures are rarely
indicated. Treatment of asymptomatic bacteriuria in this setting is unnecessary.
The Foreskin and Urinary Tract Infections
A resurgence of sentiment favoring routine neonatal circumcision has occurred in the
last decade because of recently described associations between an intact foreskin
and urinary tract infections in infants. This association was best illustrated in a series
of systematic studies by Wiswell and associates25-28 at U.S. Army hospitals. In
several large epidemiologic studies, the authors found that the incidence of
significant urinary tract infections in uncircumcised males less than six months of age
was 1 to 4 percent. The incidence in circumcised males was only 0.1 to 0.2 percent.
Because of the data demonstrating an increase in the rate of infection, routine
circumcision has been advocated by some authors. They point out the significant
mortality and renal scarring associated with urinary tract infections occurring in early
infancy. However, circumcision is a permanent solution to a problem that affects
males only during the first six months of life. There may be alternative, nonsurgical
means of preventing these infections, and the question of whether all boys should be
circumcised to prevent infection in 1 to 4 percent remains debatable. It is also
unclear whether circumcision would augment the benefit of antibiotic prophylaxis in
boys with reflux or other urologic anomalies.
Figure 1 reprinted with permission from Rushton HG, Majd M. Dimercaptosuccinic
acid renal scintigraphy for the evaluation of pyelonephritis and scarring: a review of
experimental and clinical studies. J Urol 1992;148(5 Pt 2):1726-32.
The Authors
JONATHAN H. ROSS, M.D.,
is a member of the Section of Pediatric Urology in the Department of Urology at the
Cleveland (Ohio) Clinic Foundation. He received his medical degree from the
University of Michigan Medical School, Ann Arbor, and completed a residency in
urology at the Cleveland Clinic Foundation. Dr. Ross also completed a fellowship in
pediatric urology at the Children's Hospital of Michigan, Detroit.
ROBERT KAY, M.D.,
is a member of the Section of Pediatric Urology in the Department of Urology at the
Cleveland Clinic Foundation. He graduated from the University of California, Los
Angeles, UCLA School of Medicine, and completed a residency in urology at the
Oregon Health Sciences University School of Medicine, Portland, and a fellowship in
pediatric urology at Alder Hey Children's Hospital, Liverpool, England. He is past
president of the Urologic Section of the American Academy of Pediatrics.
Address correspondence to Jonathan
Evaluation and Treatment of Urinary Tract Infections in Children
SYED M. AHMED, M.D., M.P.H., D.P.H., and STEVEN K. SWEDLUND, M.D.
Wright State University School of Medicine, Dayton, Ohio
Urinary tract infections (UTIs) are among the most common bacterial infections
encountered by primary care physicians. Although UTIs do not occur with as great a
frequency in children as in adults, they can be a source of significant morbidity in
children. For reasons that are not yet completely understood, a minority of UTIs in
children progress to renal scarring, hypertension and renal insufficiency. Clinical
presentation of UTI in children may be nonspecific, and the appropriateness of
certain diagnostic tests remains controversial. The diagnostic work-up should be
tailored to uncover functional and structural abnormalities such as dysfunctional
voiding, vesicoureteral reflux and obstructive uropathy. A more aggressive work-up,
including renal cortical scintigraphy, ultrasound and voiding cystourethrography, is
recommended for patients at greater risk for pyelonephritis and renal scarring,
including infants less than one year of age and all children who have systemic signs
of infection concomitant with a UTI. Antibiotic prophylaxis is used in patients with
reflux or recurrent UTI who are at greater risk for subsequent infections and
complications.
Urinary tract infection (UTI) is defined as the presence of bacteria in urine along with
symptoms of infection. UTIs occur in as many as 5 percent of girls and 1 to 2 percent
of boys.1 The incidence of UTI in infants ranges from approximately 0.1 to 1.0
percent in all newborn infants to as high as 10 percent in low-birth-weight infants.2
Infection of the urinary tract before age one occurs more frequently in boys than in
girls.2 After age one, both bacteriuria and UTI are more common in girls.
In preschool-age children, the prevalence of asymptomatic infections diagnosed by
suprapubic aspiration in girls is 0.8 percent, compared with 0.2 percent in boys.3 In
the school-age group, the incidence of bacteriuria among girls is 30 times that
among boys (1.2 versus 0.04 percent).4
Etiology and Pathogenesis
Escherichia coli is the most common infecting pathogen in children, accounting for up
to 80 percent of UTIs. Other pathogens include Staphylococcus and Streptococcus
species, a variety of enterobacteria (e.g., Klebsiella, Proteus) and, occasionally,
Candida albicans. The virulence of the invading bacteria and the susceptibility of the
host are of primary importance in the development of UTI.3 In neonates, the usual
route of infection is presumed to be hematogenous.1 Later in life, infection is usually
caused by ascension of bacteria into the urinary tract.5
FIGURE 1.
Relationship between urinary tract infection and loss of
renal function.
Any condition that leads to urinary stasis (renal calculi, obstructive uropathy,
vesicoureteral reflux and voiding disorders) may predispose to the development of
UTI in children.5 Renal parenchymal infection and scarring are well-established
complications of infection of the upper urinary tract in children and can lead to renal
insufficiency, hypertension and renal failure. Parenchymal scarring develops in 10 to
15 percent of children with UTI. Children less than one year of age with a UTI are at
much greater risk for renal scarring than older children; children over five years of
age uncommonly have new renal scarring with UTI.6 A 27-year follow-up study from
Sweden1 showed that focal renal scarring caused by pyelonephritis in a child carried
a 23 percent risk for hypertension and a 10 percent risk for end-stage renal disease.
Controversy continues regarding the association of vesicoureteral reflux with the
pathogenesis of renal scarring, reflux nephropathy, pyelonephritis and voiding
disorders. Although vesicoureteral reflux is associated with renal scarring,7 its role in
the pathogenesis of pyelonephritis and renal scarring is not fully understood.8
Findings from one study9 showed that scars formed in 40 percent of refluxing
kidneys and 43 percent of nonrefluxing kidneys. While some researchers emphasize
the risk of renal scarring from recurrent UTI without reflux,10 others are just as
adamant regarding the risk of scarring from reflux in the absence of infection.11 The
fact that renal scarring develops in only a minority of patients with pyelonephritis
and/or vesicoureteral reflux suggests that the development of renal scarring likely
involves the interplay of several factors and cannot simply be attributed to the
presence of infection or reflux alone (Figure 1).
Clinical Presentation
The clinical presentation of UTI is variable. In a child with so-called "asymptomatic"
bacteriuria, only subtle clues, such as enuresis or squatting, may be present.
Alternatively, a systemically ill neonate may be lethargic and hypotensive (Table 1).
Although children are often managed on the basis of clinical symptoms and signs
alone, these may be unreliable predictors of which patients are at risk for
pyelonephritis and scarring.12,13 On the other hand, radiologic tests to confirm
pyelonephritis or reflux can be expensive, time-consuming, invasive and undesirable
to parents
TABLE 1
Signs and Symptoms of Urinary Tract Infection in
Children
Urinary tract signs and symptoms
Dysuria
Frequency
Dribbling/hesitancy
Enuresis after successful toilet training
Malodorous urine
Hematuria
Squatting
Abdominal/suprapubic pain
Systemic signs and symptoms
Fever
Vomiting/diarrhea
Flank/back pain
The physical examination of a child with a possible UTI should exclude hypertension,
an abdominal or flank mass, or a palpable bladder, neurologic deficits, abnormal
genitalia and an abnormal urinary stream.1 This will help the clinician to find
associated disorders.
The presence of irritative urinary symptoms in the absence of bacteria suggests a
non-UTI cause such as vaginitis, urethritis, pinworms, or the use of bubble baths.1
Diagnosis
Maintaining a high index of suspicion for UTI in febrile children, particularly when an
unexplained fever lasts two to three days, will lessen the number of missed UTIs.
The most recent guideline issued by the American Academy of Pediatrics (AAP) for
the evaluation of fever (39.0°C [102.2°F] or higher) of unknown origin suggests
urinalysis in all cases and a urine culture in all boys younger than six months of age
and all girls younger than two years of age.15
In infants, suprapubic aspiration or bladder catheterization and, in older children, a
clean-voided midstream specimen are essential for diagnosis of UTI.1 Although
convenient, use of adhesive perineal bags or wringing liquid from a wet diaper to
collect urine is suboptimal, as bacteria from fecal contamination or urethral
colonization may be misinterpreted as UTI. Although there is debate about the best
way to screen female infants for UTI,16 many support criteria set by Dagan and
colleagues.17 According to these criteria, a finding of more than 5 white blood cells
per high-power field in centrifuged fresh urine is a satisfactory positive screening
test.
Renal cortical scintigraphy has replaced intravenous
urography as the standard technique for detecting renal
inflammation and scarring.
Pyuria, proteinuria and hematuria may occur with or without UTI.1 Conversely, UTI
can occur without pyuria.1 The determinations of nitrite concentrations and
leukocyte esterase are not sensitive enough in children to indicate the need for urine
culture.1 A properly obtained positive urine culture is essential for the diagnosis of
UTI. Any number of colonies from a suprapubic bladder aspiration, more than 103
colonies from an intermittent ("in-and-out") catheterization, and more than 105
colonies from a midstream clean-catch urine collection indicate UTI.5
Most UTIs are caused by a single organism; the presence of two or more organisms
usually suggests contamination. A urine culture is not mandatory in adolescent girls,
particularly with a first episode. With recurrent episodes, episodes that fail therapy
and in girls with pyuria without bacteriuria, a culture is recommended.
Special Issues
Recurrent UTI
Recurrent UTI is defined as two or more UTIs over a six-month period.7 It is useful
to determine whether recurrence is caused by inadequate treatment of an
unrecognized anatomic site of bacterial persistence (small infected calculus or
unrecognized anatomic abnormality).14 As mentioned previously, recurrent UTI
increases the risk of subsequent renal scarring.
Vesicoureteral Reflux
Vesicoureteral reflux is the abnormal backwash of urine into the ureter or kidney.18
The most common radiologic studies for the evaluation of reflux are the voiding
cystourethrogram and the isotope cystogram. The isotope cystogram is more
sensitive than the voiding cystourethrogram for detecting reflux, while only the
voiding cystourethrogram provides enough anatomic detail to identify the severity of
reflux and the presence of anatomic abnormalities.
Because the isotope cystogram exposes the patient to less radiation than the voiding
cystourethrogram, it may be the study of choice for follow-up evaluations and may
be used as the initial study in girls.18 In boys, however, initial work-up should
include a voiding cystourethrogram to detect urethral abnormalities such as urethral
diverticulum or posterior urethral valves. Grades I and II reflux can be treated with
antimicrobial prophylaxis along with a strict voiding regimen19; however, urologic
consultation should be considered in grades III to V reflux as the condition may
merit surgical correction.5
Breakthrough UTI
Breakthrough UTI may be caused by a change in the resistance pattern of organisms
colonizing the urethra, noncompliance, vesicoureteral reflux or voiding dysfunction.
Recognizing and addressing these associated factors are essential in treating
breakthrough UTI. A study in girls showed that treatment of voiding dysfunction
combined with double antimicrobial prophylaxis was significantly successful in
preventing breakthrough UTI.20
Voiding Dysfunction
Voiding dysfunction is a general term encompassing several patterns of detrusor
instability and incomplete bladder emptying seen on urodynamic testing. It is often
associated with daytime enuresis and constipation.20 Patients with otherwise
unexplained recurrent UTI, especially in the setting of daytime enuresis or
constipation, may merit urodynamic testing. Children with voiding dysfunction are at
increased risk for the development of vesicoureteral reflux and UTI. Treatment of
voiding dysfunction includes timed voiding, treatment of constipation, prophylactic
antibiotics and, in some cases, use of anticholinergic medication (e.g., oxybutynin
[Ditropan] or propantheline [Pro-Banthine]) or biofeedback.
Asymptomatic Bacteriuria
Controversy continues regarding the need for antibiotic treatment of asymptomatic
bacteriuria.21-25 If recurrent bacteriuria is truly asymptomatic, no antimicrobial
treatment may be the best option, as some studies have shown that asymptomatic
children are at very low risk of renal scarring, and prophylactic treatment did not
decrease the risk of UTI recurrence.14
Diagnostic Imaging
There is more controversy than consensus regarding the appropriateness of different
diagnostic imaging modalities in the evaluation of UTI in children.26-28 The most
commonly used imaging techniques are discussed in the following sections.
Ultrasonography
Although intravenous urography has been a time-honored examination in the initial
radiologic evaluation of UTI in children,9 ultrasonography has largely replaced
intravenous urography as the initial screening examination.8 Ultrasonography alone
is not generally adequate for investigation of UTI in children, as it is unreliable in
detecting vesicoureteral reflux, renal scarring or inflammatory changes.29 If reflux or
morphologic abnormalities are identified, renal scintigraphy and voiding
cystourethrography are recommended to further search for renal scarring or urinary
tract abnormalities.
Intravenous Urography
Intravenous urography provides a precise anatomic image of the kidneys and can
readily identify some urinary tract abnormalities (e.g., cysts, hydronephrosis).30 The
major disadvantages of intravenous urography include decreased sensitivity
compared with renal scintigraphy in the detection of both pyelonephritis and renal
scarring.30 Higher dosage of radiation and risk of reaction to contrast medium are
also reasons for concern. Given these disadvantages, intravenous urography appears
to have little role in the work-up of UTI in children.
Renal Cortical Scintigraphy
Renal cortical scintigraphy has replaced intravenous urography as the standard
technique for the detection of renal inflammation and scarring.8 Renal cortical
scintigraphy with either technetium-99mlabeled glucoheptonate or
dimercaptosuccinic acid (DMSA) are both highly sensitive and specific.8 DMSA
scanning offers the advantages of earlier detection of acute inflammatory changes
and permanent scars compared with ultrasound or intravenous urography. It is also
useful in neonates and patients with poor renal function. Computed tomography (CT)
is sensitive and specific for the detection of acute pyelonephritis, but no study is
available that compares CT and scintigraphy.8 Furthermore, CT is more expensive
than scintigraphy and exposes the patient to higher levels of radiation, and its use is
not supported by evidence.
Voiding Cystourethrography
Because vesicoureteral reflux is a risk factor for reflux nephropathy and renal scars,
early identification of this condition is warranted.4 Voiding cystourethrography
should be delayed until after urinary infection is controlled, because vesicoureteral
reflux may be the transient effect of infection. However, because of low sensitivity
and specificity, and because voiding cystourethrography involves gonadal irradiation
and catheterization, its use in diagnosing vesicoureteral reflux has been
questioned.31
Isotope Cystogram
Although the isotope cystogram causes the same discomfort as bladder
catheterization used in voiding cystourethrography, it has the advantage of an
ionization radiation dose that is only 1 percent of that used for voiding
cystourethrography,5 and its continuous monitoring is also more sensitive for
identifying reflux than the intermittent flouroscopic monitoring of voiding
cystourethrography.
Table 2 reviews the medical imaging techniques used in evaluating UTI in children.
TABLE 2
Advantages and Disadvantages of Diagnostic Imaging in
Evaluation of Urinary Tract Infection in Children
Imaging study
Advantages
Disadvantages
Ultrasound
Measures renal size
and shape Identifies
hydronephrosis,
structural or
anatomic
abnormalities and
renal calculi
No radiation
Not reliable to
detect
vesicoureteral
reflux, renal
scarring or
inflammatory
changes
Intravenous
urography
Not as reliable to
detect renal
scarring or
Precise anatomic
pyelonephritis
image of the kidneys
High radiation dose
Estimates renal
Risk of reaction to
function
contrast medium
Poor detail in
infants
Renal cortical
scintigraphy
Detects
pyelonephritis and
renal scarring even in
Does not evaluate
early stages
collecting system
Useful in neonates
Cannot detect
Little radiation
obstruction
Useful in patients
with poor renal
function
Computed
tomography
Provides both
anatomic and
Expensive
functional
High radiation
information about the
Few clinical or
kidney
experimental data
Possibly more
to support its use at
sensitive in
present
diagnosing
pyelonephritis
Assesses the size and
shape of bladder
Detects and grades
Voiding
Gonadal radiation
vesicoureteral reflux
cystourethrography
Catheterization
Evaluates posterior
urethral anomalies in
boys
Treatment
Therapeutic trials in children with UTI are rare and poorly controlled.32 Thus,
controversy regarding dosage or length of therapy with antimicrobials continues. In
patients who appear toxic, it is reasonable to initiate treatment with intravenous
antibiotics and follow them closely for signs and symptoms of infection (fever, severe
pain); these usually resolve in three to five days.33 Initial antibiotic therapy should
be based on age, clinical severity, location of infection, presence of structural
abnormalities, and allergy to certain antibiotics. Treatment generally begins with a
broad-spectrum antibiotic, but it may need to be changed based on the results of
urine culture and sensitivity testing.
Hospitalization is suggested for symptomatic young infants (less than three months
of age) and all children with clinical evidence of acute severe pyelonephritis (high
fever, toxic appearance, severe flank pain).33
The duration of outpatient treatment for patients with a less toxic appearance and
uncomplicated UTI (no systemic signs of infection) is also controversial.1 Evidence is
lacking for the use of short-course therapy in children with UTI.26 Although
conventional therapy lasts seven to 10 days, a three- to seven-day trial of oral
antibiotics has been suggested for uncomplicated infection of the lower urinary
tract.32
TABLE 3
Antimicrobial Drugs Used in the Treatment of Urinary
Tract Infection in Children
The rightsholder did not grant rights to reproduce this item in
electronic media. For the missing item, see the original print
version of this publication.
Reasonable choices for initial inpatient and outpatient oral antibiotic therapy are
shown in Table 3.24 Because of the possibility of bacterial resistance to a
prophylactic agent used for long-term suppression, the treating antimicrobial agent
for a breakthrough UTI should, ideally, be different from the prophylactic agent17
(Table 3).
Follow-up and Chemoprophylaxis
A urine culture should be obtained three to seven days after the completion of
treatment to exclude relapse. Prophylaxis is recommended for all children younger
than five years of age with vesicoureteral reflux (who are not surgical candidates) or
other structural abnormalities and in children who have had three documented UTIs
in one year.1 With careful monitoring for side effects, a prophylactic trial of a single
nightly dose of nitrofurantoin (Furadantin, Macrodantin), 1 to 2 mg per kg per day,
or trimethoprim-sulfamethoxazole (Bactrim, Septra), 2 mg per kg of trimethoprim
per day, may be used for six months or more.8 Using low doses of antibiotics for
prophylaxis has a theoretic advantage since this may minimize serum levels and
subsequent enteric bacterial resistance while urinary concentration of the antibiotic
remains high enough to maintain sterile urine.14
Prevention/Patient Education
A common-sense approach to prevention is advised by most authors.24,34 Good
hygiene (including "front-to-back" wiping after urination in girls), avoidance or
correction of constipation, and avoidance of bubble baths, chemical irritants and tight
clothing might be recommended.
The role of circumcision in preventing UTI is controversial.25,35 The AAP states that
"newborn circumcision has potential medical benefits and risks." When circumcision
is being considered, the benefits and risks should be explained to the parents, and
informed consent should be obtained.36
Final Comment
In light of the controversies and current literature, we propose our outline of
management of UTI in children (Figures 2, 2a and 2b).
FIGURE 2
Algorithm for the management of urinary tract infection in children.
See Figures 2a and 2b for treatment groups A and B. (UTI=urinary
tract infection; VCUG=voiding cystourethrography)
For a primary care physician, it is imperative to maintain a high index of suspicion
for UTI in children. By uncovering UTI and associated disorders, the goal of
preventing renal infections, renal insufficiency, hypertension and end-stage renal
disease can be realized.
In any child with systemic signs of illness, treatment with parenteral antibiotics
should be initiated, and after clinical improvement, therapy
should be switched to oral antibiotics for 10 to 14 days. Diagnostic imaging with
ultrasound and renal cortical scintigraphy should be considered to document the
presence of pyelonephritis or renal scarring; voiding cystourethrography should be
performed when the urine is sterile and the patient is clinically improved. Further
management is dictated by the clinical course and findings on medical imaging
(Figure 2a).
FIGURE 2A
Algorithm for treatment group A.
FIGURE 2B
Algorithm for treatment group B.
In all patients less than five years of age with no systemic signs and in boys over age
five with no systemic signs, treatment with oral antibiotics should be carried out for
10 to 14 days. Afterward, diagnostic imaging with ultrasound and voiding
cystourethrogram should be considered. Further management is dictated by findings
on diagnostic imaging and clinical course (Figure 2b).
In girls over five years of age with no systemic signs, treatment with oral antibiotics
should be carried out for seven to 10 days. Diagnostic imaging in these patients is
not necessary with the first UTI but may be indicated in cases of recurrent UTI.
Further management is outlined in Figure 2b.
The authors thank Leonardo M. Canessa, M.D., Jeanne P. Lemkau, Ph.D., Ahmed
Hamidinia, M.D., and Juan Palomar, M.D., for reviewing the manuscript. The authors
also thank Julie Mougey for assistance in the preparation of the manuscript.
The Authors
SYED M. AHMED, M.D., M.P.H., PH.D.,
is assistant professor in the family practice residency program at Wright State
University School of Medicine/ Miami Valley Hospital, Dayton, Ohio. Dr. Ahmed is a
graduate of Sir. Salimullah Medical College, Dhaka University, Dhaka, Bangladesh.
He completed a residency and fellowship in family medicine at Baylor College of
Medicine, Houston.
STEVEN K. SWEDLUND, M.D.,
is associate clinical professor in the Department of Family Practice at Wright State
University School of Medicine and associate director of the Miami Valley Hospital
Family Practice Residency. He earned a medical degree from Southern Illinois
University School of Medicine, Springfield, and completed a residency in family
medicine at St. Elizabeth Medical Center, Dayton.
Urinary Tract Infections in Children: Why They Occur and How to Prevent
Them
STANLEY HELLERSTEIN, M.D.,
University of MissouriKansas City School of Medicine and Children's Mercy Hospital,
Kansas City, Missouri
Urinary tract infections (UTIs) usually occur as a consequence of colonization of the
periurethral area by a virulent organism that subsequently gains access to the
bladder. During the first few months of life, uncircumcised male infants are at
increased risk for UTIs, but thereafter UTIs predominate in females. An important
risk factor for UTIs in girls is antibiotic therapy, which disrupts the normal
periurethral flora and fosters the growth of uropathogenic bacteria. Another risk
factor is voiding dysfunction. Currently, the most effective intervention for
preventing recurrent UTIs in children is the identification and treatment of voiding
dysfunction. Imaging evaluation of the urinary tract following a UTI should be
individualized, based on the child's clinical presentation and on clinical judgment.
Both bladder and upper urinary tract imaging with ultrasonography and a voiding
cystourethrogram should be obtained in an infant or child with acute pyelonephritis.
Imaging studies may not be required, however, in older children with cystitis who
respond promptly to treatment.
Urinary tract infections (UTIs) are common in children. The treatment goals are to
eliminate the infection and prevent kidney damage. The usual approach in children is
to first treat the infection and then obtain imaging studies of the urinary tract. This
article focuses on why children have UTIs and what can be done to prevent them.
Factors That Predispose Children to UTIs
Circumcision
Uncircumcised male infants appear to be at increased risk of UTIs in the first three
months of life. In a study of 100 otherwise healthy infants ranging in age from five
days to eight months and admitted to the hospital because of a first known UTI,1
most of the UTIs in infants younger than three months of age were in males, but
female infants predominated thereafter. The fact that 95 percent of the male infants
in the study were not circumcised led to speculation that the uncircumcised male has
an increased susceptibility to UTI--at least early in life.
This issue was examined in a retrospective study at Tripler Army Medical Center.2
The study showed that uncircumcised boys had a 4.1 percent incidence of UTI during
their first year of life, while girls had an incidence of 0.5 percent and circumcised
males an incidence of 0.2 percent. Subsequently, a large retrospective study of
infants cared for in U.S. Army hospitals supported the theory that circumcision
protects against UTIs in young male infants. The periurethral area was found to be
more frequently and more heavily colonized with uropathogens, especially
Escherichia coli, in uncircumcised infants than in circumcised infants.3
Winberg and associates4 offer an explanation for the high incidence of UTIs in
uncircumcised male infants in an intriguing article, "The Prepuce: A Mistake of
Nature?" They suggest that one unphysiologic intervention--circumcision--serves to
counterbalance the effect of another unphysiologic state of affairs--exposure of the
infant to the microbiologic environment of the maternity unit. In a natural biologic
setting, with no perineal shaving or cleansing, mothers often defecate when giving
birth in a squatting or kneeling position. Because of this, the infant is colonized at
birth with the mother's aerobic and anaerobic bacteria. The infant receives specific
protection against infection from these bacteria through immunoglobulins transferred
from the mother during gestation and after delivery in the mother's breast milk.
In contrast, babies born and cared for in a hospital are likely to be colonized by
strains acquired from the external environment, against which their mothers may
have no immunity. Such infants have little protection against infection from hospitalacquired strains of E. coli that colonize the gastrointestinal tract, the perineum and
the periurethral area in females and preputial area in uncircumcised males.
Colonization of the prepuce by these potentially dangerous bacteria places the
uncircumcised male at high risk for a UTI. Circumcision diminishes that risk.
Changes in the Periurethral Flora
It is not only in the male that the character of the periurethral flora is a key factor in
the occurrence of UTIs. After the first few months of life, UTIs occur far more
frequently in girls than in boys, presumably because of the shorter length of the
female urethra. Following birth, heavy periurethral colonization with aerobic bacteria
normally becomes established in both sexes.5 Colonization with E. coli and
enterococci diminishes during the first year and normally becomes light after five
years of age.
Adult women prone to recurrent UTIs have colonization of the periurethral area with
the specific microbe that will cause the next infection.6 Similar findings were
demonstrated in studies of UTIs in school-aged girls.7,8 The periurethral area is
colonized by both anaerobic and aerobic bacteria from the gastrointestinal tract,
which serve as part of a normal defense barrier against pathogenic microorganisms.
Voiding dysfunction is treated with the use of a
retraining program that emphasizes good voiding
technique, using a timed voiding schedule.
Two studies indicate that breast feeding protects against UTIs, both during the time
the infant is receiving breast milk and for a period after breast feeding is
discontinued, presumably by promoting a stable intestinal flora with fewer potentially
pathogenic strains.9,10 Disturbance of the normal periurethral flora fosters
colonization by potential uropathogens. Experimental and clinical studies show that
resistance to colonization by uropathogens can be broken down by administration of
amoxicillin or a first-generation cephalosporin (Cephadroxil).11 Of special interest is
a study of girls with respiratory infections treated with trimethoprimsulfamethoxazole; the study showed that this antimicrobial agent did not disturb the
normal flora.12
Voiding Dysfunction
Voiding dysfunction is characterized by some or all of the following: urgency,
frequency, dysuria, hesitancy, dribbling of urine and overt incontinence. Symptoms
of voiding dysfunction may be secondary to a UTI or to local irritants such as
pinworm infestation or bubble bath, or hypercalciuria.
In the anatomically and neurologically normal child, voiding dysfunction is usually
caused by persistence of an unstable urinary bladder, an important contributor to
recurrent UTIs. An unstable urinary bladder is a common functional disorder and
usually has been present since daytime urinary control was first developing in the
child. The outstanding characteristic is persistent urinary urgency.
Recognition and management of voiding dysfunction is the area in which the
physician can be most effective in the prevention of recurrent UTIs. A girl with
voiding dysfunction is at increased risk for recurrent UTIs because of reflux of urine
laden with bacteria from the distal urethra into the bladder.13 Studies have
demonstrated that reflux of contrast material from the distal urethra into the bladder
occurs when continence is maintained by contraction or compression of the bladder
outlet rather than by the normal neurogenic inhibition of the detrusor contraction.
Normally, the distal urethra is not sterile but has a flora similar to that of the
periurethral area. When urinary leakage is prevented by compression of the urethral
sphincter during an uninhibited contraction, the flat bladder base becomes funnel
shaped and the posterior urethra is filled with urine. Shortly thereafter, when the
contraction subsides, bacteria-laden urine from the urethra may reflux back into the
bladder. Reflux of contaminated urine into the bladder, which itself may have an
increased susceptibility to infection because of ischemia resulting from uninhibited
detrusor contraction, is the explanation for recurrent UTIs in many children.
A relationship between constipation and UTIs is well known.14 It has been shown
that constipation per se, with a dilated rectum, causes the same pattern of voiding
dysfunction as that encountered in children with persistence of an unstable bladder.
Effective treatment of the constipation results in normalization of bladder function
and cessation of UTIs.15
Prevention of UTIs
The first step in the prevention of UTIs in the neurologically intact child with an
unobstructed urinary tract is to ask, "Why does this child have a UTI at this time?" A
detailed voiding and defecation history should be obtained. Recent treatment of an
upper respiratory infection with amoxicillin or a cephalosporin may indicate the need
to try to avoid prescribing these agents for the child in the future. However, if
amoxicillin or a cephalosporin is required for treatment of an upper respiratory
infection, it is important not to discontinue therapy with nitrofurantoin (Macrodantin)
or trimethoprim-sulfamethoxazole (Bactrim, Septra) in the child who is receiving
suppressive antimicrobial therapy to prevent recurrent UTIs. We frequently
encounter a child with recurrence of a UTI when this happens, possibly because of
the effect on the periurethral flora or because of the high incidence of amoxicillinresistant E. coli.
Physical examination should include careful inspection of the lumbosacral area for
signs of underlying dysraphism (pilonidal sinus, tuft of hair, etc.). A rectal
examination should be performed to detect a large fecal reservoir, even if there is no
history of constipation.
Voiding dysfunction is treated with the use of a voiding retraining program that
emphasizes good voiding technique, usually following a timed voiding schedule. In
many instances a pharmacologic agent such as oxybutynin (Ditropan), propantheline
(ProBanthine) or hyoscyamine sulfate (Levsin) is helpful. The goal is to eliminate the
episodes of urinary urgency, during which there may be reflux of bacteria-laden
urine from the distal urethra into the urinary bladder. Anticholinergic agents not only
alter bladder function but also suppress intestinal motility, so attention to
constipation must be ongoing.
A diagnosis based on a bagged urine specimen positive
for pyuria, bacteriuria or nitrite in a symptomatic patient
should be confirmed with a catheter or suprapubic urine
specimen.
UTI Prevention Myths
Some forms of intervention to prevent recurrent UTIs in children, mainly young girls,
appear to be based more on myth than on substance. Perineal hygiene is regularly
emphasized. For aesthetic reasons, it seems appropriate to instruct girls to wipe
from front to back, but no data indicate that this practice prevents vaginal and vulval
colonization with Enterobacteriaceae.16 According to Kunin,17 the commonly held
view that UTIs in women are caused by fecal contamination of the periuretheral zone
is unproved. If UTIs were caused by fecal contamination, one would expect to find
multiple strains of E. coli in the vaginal introitus and periurethral area of these
women. However, women prone to recurrent UTIs are colonized by a single
pathogen, while healthy adult females have few or no E. coli in these areas.18 If
fecal soiling were an important factor in the pathogenesis of UTIs, female infants
would have a very high incidence of UTIs prior to achieving bowel control.
Some girls prone to recurrent UTIs are told that they should give up tub-bathing and
swimming. These suggestions are based on the concept that UTIs in girls are a result
of vulvourethral reflux of tub or pool water into the bladder. However, a careful
study of this possibility, using inulin as a tracer in bath water, failed to show inulin in
bladder urine.19 There appears to be no basis for the suggestion that girls eliminate
bathing or swimming in order to prevent UTIs.
A significant segment of the U.S. population believes that cranberry-derived
beverages prevent or cure UTIs. The presumed antibacterial effects of cranberry
juice are controversial, attributed by some to urinary acidification and by others to a
direct bacteriostatic effect of hippuric acid on E. coli.20 Clinical studies have not been
convincing. At this juncture, it seems reasonable not to discourage children who are
prone to UTIs, and who like and tolerate cranberry-derived beverages, from
ingesting them, while emphasizing that these beverages cannot be viewed as a
substitute for an antibiotic in the treatment of a UTI or as a substitute for other
measures to prevent reinfection.
Diagnosis of UTIs
The specimen for urinalysis and culture should be obtained by catheter or suprapubic
aspiration in the infant or child unable to void on request. Suprapubic aspiration is
the method of choice in the uncircumcised male. A midstream clean-catch specimen
may be obtained from the child with urinary control. A bagged specimen of urine that
shows no growth or fewer than 10,000 colony-forming units (CFU) per mL is
evidence of the absence of a UTI. If the child who has not yet achieved urinary
control has symptoms that mandate immediate treatment, and analysis of the urine
specimen obtained by bag shows pyuria, or tests for positive nitrite or bacteriuria, a
urine sample should be obtained by suprapubic aspiration or catheter before starting
antibiotic therapy because of the high incidence of false-positive bagged urine
cultures.
Treatment of acute pyelonephritis or cystitis may be initiated based on the urinalysis
findings. However, the diagnosis of a UTI is not documented by urinalysis, and
imaging studies of the urinary tract should not be obtained until the diagnosis of UTI
is confirmed by a positive urine culture.
Cystitis
Infants and young children with cystitis who have not yet achieved urine control
often present with low-grade fever (usually less than 38°C [100.4°F]), discomfort or
crying with urination, mild behavior change and, at times, foul-smelling urine. Older
children with cystitis usually present with any or all of the following: urinary urgency,
frequency, hesitancy, dysuria and, at times, incontinence. No fever or only a lowgrade fever is present. Some children have suprapubic pain or tenderness. A
tentative diagnosis of cystitis may be made if there are urinary findings on the
dipstick examination or microscopic evidence suggestive of a UTI.
Ultrasound examination can detect obstructive
abnormalities; a cystourethrogram detects
vesicoureteral reflux.
Acute Pyelonephritis
Acute pyelonephritis may be diagnosed in the infant or young child with fever (a
rectal or tympanic membranederived temperature of 38°C [100.4°F] or greater)
unexplained by the history or physical examination and urinary findings suggestive of
a UTI--i.e., positive nitrite and/or leukocyte esterase and/or bacteria in the
centrifuged urinary sediment. A good rule is that urine should be evaluated for the
presence of infection in the infant or young child who has an unexplained fever for as
long as three days. Acute pyelonephritis may be diagnosed in the older child with
fever, systemic symptoms, costovertebral angle or flank tenderness and urinary
findings suggestive of a UTI.
Asymptomatic Bacteriuria
Children, usually school-aged girls, with significant bacteriuria in the absence of any
symptoms do not require further evaluation of the urinary tract or treatment. An
exception, of course, are children asymptomatic at the time a urine specimen is
obtained who have a history of vesicoureteral reflux or recurrent UTIs.
Imaging Evaluation Following a UTI
An algorithm for the management of children with the presumptive diagnosis of a
UTI is presented in Figure 1. The literature describing various protocols for the
imaging evaluation of the urinary tract following a UTI is extensive. Unfortunately, no
prospective studies with long-term outcome data are available.21 Some experts
recommend that all children with a UTI be investigated with urinary tract
ultrasonography. With regard to children younger than one year, two years or five
years, some experts recommend urinary tract ultrasonography and cystography.2226 Some would obtain only cortical imaging (DMSA or glucoheptonate nuclear scans)
or cystography if these studies are normal. In addition, there are those who suggest
that no imaging is needed in the child with cystitis who responds promptly to
treatment.27-29
FIGURE 1
Algorithm for the management of children with a presumptive
diagnosis of UTI.
UTI=urinary tract infection; IV=intravenous; US=ultrasound examination.
* --In children with a UTI, a cystogram may be obtained when the urine is
free of bacteria and pus cells and the voiding pattern has reverted to the
pattern that was present before the UTI.
† --Suppressive antibiotic therapy is recommended for 6 months in all
children who have had acute pyelonephritis but may be continued longer in
those with vesicoureteral reflux.
Suggested Imaging Evaluation of a Child with a UTI
Children who are to have a cystogram as part of the imaging evaluation for a UTI
should receive therapeutic or suppressive doses of antibiotic until after the bladder
imaging study. The following recommendations for the imaging evaluation of children
following a UTI are based on a review of the literature, experience and reason.
" In the neonate with urosepsis and in the infant, child or adolescent with a clinical
diagnosis of acute pyelonephritis documented by urine culture:
1. Urinary tract ultrasound examination to identify an obstructive abnormality.
2. A contrast voiding cystourethrogram to evaluate the urinary bladder and urethra
and detect vesicoureteral reflux.
Management of the acute illness is based on the clinical diagnosis of acute
pyelonephritis. A significant obstructive abnormality will be disclosed by ultrasound
examination. If vesicoureteral reflux is present, long-term suppressive antibiotic
therapy may be indicated.30 Some clinicians recommend six months of suppressive
antibiotic therapy for children who have pyelonephritis in the absence of
vesicoureteral reflux (nonrefluxing pyelonephritis). This is, however, an empiric
recommendation related to the relatively high recurrence rate of UTIs in girls in the
first months following a primary infection.
" In the infant or child from about one to five years of age who has had one or
several episodes of cystitis that responded promptly to therapy:
1. Imaging evaluation after a first episode of cystitis if the child has a history of
unexplained fever or there is a family history of vesicoureteral reflux.
2. Urinary tract ultrasonography to identify structural abnormalities.
3. Nuclear cystogram to detect vesicoureteral reflux in girls who have a normal
voiding pattern when they are uninfected.
4. Contrast voiding cystourethrogram in all boys and girls who have an abnormal
voiding pattern. The study should be done when the child is free of infection.
" In the child older than five years after one or several episodes of cystitis:
1. Urinary tract ultrasonography in all children except a pubescent girl who may have
become sexually active. (If a pubescent girl has several episodes of clinical cystitis
within a year, a urinary tract ultrasound examination should be obtained.) No further
studies are required if the ultrasound examination is normal.
2. If the ultrasound examination is abnormal, contrast cystourethrogram should be
performed in all children with one or several episodes of cystitis.
The literature review for the manuscript was done in preparation for the Stanley
Levine, M.D., Memorial Lecture, presented on April 4, 1997, at the Schneider
Children's Hospital, Long Island, N.Y. The author thanks Carol Burns for secretarial
support in the preparation of both the lecture and the manuscript.
The Author
STANLEY HELLERSTEIN, M.D.,
is professor of pediatrics at the University of Missouri Kansas City School of Medicine
and a member of the Section of Pediatric Nephrology at Children's Mercy Hospital,
also in Kansas City, Mo. He graduated from the University of Colorado School of
Medicine, Denver, and completed an internship and pediatric residency at Indiana
University Medical Center, Indianapolis. After a two-year fellowship in fluid and
electrolyte metabolism at the University of Kansas School of Medicine, Kansas City,
Kan., and Children's Mercy Hospital, Dr. Hellerstein spent six years in private
practice. He then returned to Children's Mercy Hospital, where he founded the
Section of Pediatric Nephrology. Over the past 25 years, the evaluation and
management of children with urinary tract infections has been the focus of much of
his clinical, research and scholarly efforts.