Urinary tract infections in children and their renal repercussions

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JUNIOR, Maurício Jorge Andrade [1], TORRES, Fernanda Rodrigues [2], RODRIGUES, Simone Alves Pereira [3], ARAÚJO, Diva Floriano Machado de [4]

JUNIOR, Maurício Jorge Andrade. Et al. Urinary tract infections in children and their renal repercussions. Revista Científica Multidisciplinar Núcleo do Conhecimento. 04 year, Ed. 08, Vol. 04, pp. 38-45. August 2019. ISSN: 2448-0959. Acess Link: https://www.nucleodoconhecimento.com.br/health/urinary-tract


Urinary tract infection (UTI) is a common and important clinical problem in childhood. High UTI, i.e., acute pyelonephritis can lead to renal healing, hypertension, and end-stage renal disease. Although children with pyelonephritis tend to have fever, it is often difficult, for clinical reasons, to distinguish cystitis from pyelonephritis, particularly in children under two years. Acute urinary tract infections are relatively common in children, with 8% of girls and 2% of boys having at least one episode at seven years of age. The most common pathogen is Escherichia coli, responsible for approximately 85% of urinary tract infections in children. Renal pareatomatous defects are present in 3 to 15% of children within one to two years after the first diagnosis of urinary tract infection. The relevance of the theme is to address how the disease settles, and the way the kidneys can be compromised by UTI, serving as a warning regarding prevention, care, treatments and medications. This article aimed to analyze UTI and its renal outcomes in children. The method of bibliographic review is used through research in scientific articles of online platforms, such as SciElo, Bireme, MedLilacs related to the theme in question. The results were shown after the analysis of scientific articles and academic studies on the subject were unveiled and published in the discussion and results.

Keywords: Kidney disease, infection, urinary tract, childhood, pyelonephritis.


Urinary Tract infection (UTI) can be conceptualized by bacterial presence in urine, having as a minimum limit defined the existence of 100,000 units forming bacterial colonies per milliliter of urine (cfu/ml) (RORIZ-FILHO et al, 2010).

Many new cases that focus on the etiology and pathophysiology of urinary tract infections (UTIs) in children have emerged since the last decade, according to the authors studied. The role of bacterial virulence in the etiology of urinary tract infections has been emphasized by our scholars in infectious diseases. Several genetically coded bacterial virulence factors have been identified that increase the potential of uropatogenic organisms to cause symptomatic diseases, such as the ability of certain strains of bacteria to adhere to or bind to the human uroepithelium. The interaction with these virulence factors is a multiplicity of host defense factors that operate at all levels of the urinary tract, ranging from the perineum to the renal parenchyma. These complex parasite-host interactions determine an individual’s susceptibility to urinary infection (LOPES E TAVARES, 2004).

The clinical signs and symptoms of a urinary tract infection depend on the age of the child, but all febrile children aged between two months and two years without obvious cause of infection should be evaluated for the diagnosis of UTI (with the exception of circumcised boys over 12 years) (KOCH, ZUCCOLOTTO, 2002; WHITE, 2011).

According to Roriz-filho et al, apud Lopes and Tavares (2004): The signs and symptoms associated with urinary infection include polluria, voiding urgency, dysuria, alteration in the color and aspect of urine, with the appearance of blurred urine accompanied by changes in urinary sediment, hematuria and piuria (>10,000 leukocytes/mL). It is common the occurrence of abdominal pain more notably in topography of the hypogastrium (bladder projection) and dorsum (projection of the kidneys) and fever may arise (RORIZ-FILHO ET AL, apud LOPES E TAVARES, p.124, 2004).

Newborns with UTI may present with jaundice, sepsis, growth failure, vomiting, or fever. In infants and young children, typical signs and symptoms include fever, strong-smelling urine, hematuria, abdominal or lateral pain, and recent-onset urinary incontinence. School-age children may have symptoms similar to adults, including dysuria, frequency, or urgency. Boys are at increased risk of UTI if they are less than six months old, or if they are less than 12 months old and not circumcised. Girls usually have an increased risk of UTI, particularly if they are less than a year old. Physical examination findings may be nonspecific, but may include suprapubic sensitivity or costovertebral angle sensitivity (HANSSON et al, 1999).

May be symptomatic or asymptomatic, urinary infection in the absence of symptoms is called asymptomatic bacteriuria. As far as location is to be done, it can be classified as low or high. UTI can compromise only the low urinary tract, characterizing the diagnosis of cystitis, or simultaneously affect the lower and upper urinary tract, configuring high urinary infection, also called pyelonephritis (RORIZ-FILHO et al, 2010).

Most cases of uncomplicated UTI respond promptly to outpatient antibiotic treatment leaving no sequelae. Hospitalization is suggested for symptoms in children (less than two months of age) and all children with severe clinical evidence of acute pyelonephritis (high fever, toxic appearance, severe flank pain). Initial antibiotic therapy should be based on age, clinical severity, infection position, presence of structural abnormalities, and allergy to certain antibiotics (LO, RAGAZZI, GILIO, MARTINEZ, 2010).

Machado and Fonseca (2016) explain that treatment usually begins with a broad spectrum of antibiotics, but may need to be changed based on the results of the culture test and urine sensitivity. Parenteral antibiotics can be used daily with follow-up until the patient is afebril for 24 hours, completing between 10-14 days of therapy with an oral antibiotic (which is active against infecting bacteria).


This review is based on publications that addressed the present theme, chosen by a selective survey in the pubmed, scopus, scielo databases, as well as media data, analysis of data from the United Nations Children’s Fund (UNICEF) and the World Health Organization (WHO) in relation to the number of cesarean sections in Brazil.


Urinary tract infection (UTI) is the most common severe bacterial infection in young children. Up to 8.4% of girls and 1.7% of boys will have UTI in the first 6 years of life. UTIs cause short-term morbidity, such as fever, dysuria, and pain, and may also result in permanent scarring of the kidneys.

It is believed that many factors, such as age, sex, race and circumcision, increase the risk of recurrence of UTI, but in recent decades, no factor has received more attention than vesicoureteral reflux (VUR). In this condition, which occurs in 30% to 40% of children who have had UTI, 9 urine flows back toward the kidneys during bladder contraction.

VUR is associated with an increased risk of recurrent UTI and renal scarring, but it is neither necessary nor sufficient for any of these outcomes.

In recent years, there has been a growing appreciation that other factors, bladder and intestinal dysfunction (VID) and defects in innate immunity, may also be important contributors to the recurrence of UTI.

DBC, also known as dysfunctional urination and dysfunctional elimination syndrome, refers to abnormalities in filling and/or emptying the bladder, which manifest as frequency, urgency, and urinary incontinence; containment maneuvers; dysuria; prolonged voiding intervals; and abnormal intestinal patterns, including constipation and encopresis.

DVI is relatively common in the pediatric population, is often underdiagnosed and undertreated by primary care physicians, and is a risk factor for persistence of VUR and renal scarring.


A common sense approach to prevention is recommended by most authors. Good hygiene (including “front-to-back” cleaning after urination in girls), avoid constipation, circumcision and avoid foam baths, hygiene products with chemical ingredients that can cause irritation and tight clothing.

UTI is a common pediatric problem with the potential to produce long-term morbidity. Young children with fever with no sign of localization should always be evaluated for UTI (PAIVA, 2009; RORIZ FILHO, 2010).

Urinary tract infection (UTI) is a common bacterial disease in children. Acute pyelonephritis (APN) in children can lead to renal healing, which results from complex interactions between the host and bacterial factors, leading to acute pareymyotic damage and subsequent permanent damage1). Extensive healing may progress to posterior kidney injury with subsequent hypertension, decreased renal function, proteinuria, and sometimes end-stage renal disease (CRAIG, SIMPSON, WILLIAMS, 2009; LO, RAGAZZI, GILIO, MARTINEZ, 2010).

Permanent renal healing was observed after UTI in 15 to 60% of affected children. These large variations may be due to different sample sizes and the inclusion of heterogeneous patient populations with age variations, gender distribution, diagnostic criteria for UTI, degree of reflux, comorbid urological anomalies and genetic history. Recently, there have been reports that 17% of infants with APN confirmed with renal scintigraphy with Acido Dimercaptossuccínico (DMSA) with technetium Tc 99m had permanent renal scars on renal scintigraphy with accompanying DMSA, relatively lower incidence than previously reported (JAKOBSSON, ESBJORNER , HANSSON, 1999, ARAP, TROSTER, 2003, MACHADO, FONSECA, 2016).

Risk factors for renal scar formation in children after UTI have been reported for including: age at presentation; gender; recurrent infection; fever peak; delay in treatment; presence of vesicoureteral reflux (VUR); laboratory inflammation indices, such as total leukocyte count (WBC), erythrocyte sedimentation rate, and C-reactive protein level (PCR); bacterial virulence; host defense factors; and genetic subsceptibility (SIMOES E SILVA, OLIVEIRA, 2015; MACHADO, FONSECA, 2016)

These factors have varied among studies due to difficulties in the accurate diagnosis of UTI in young children, especially infants, because sterile urine collection is difficult and UTI symptoms are nonspecific. Thus, many studies may have patients enrolled without UTI. Moreover, although renal scintigraphy with DMSA is considered accurate for the diagnosis of NPA due to its high sensitivity and specificity in detecting renal inflammation, this method has a limited ability to differentiate between acute inflammation and renal scarring (CARVALHAL, ROCHA, MONTI, 2006; VASCONCELOS, LIMA, CAIAFA, 2006).

Many reports have investigated children in a wide age group. Renal scars, which may have developed in older children after unrecognized UTIs, cannot be differentiated from acute photon defects in renal scintigraphy with DMSA. Finally, the relationship between VUR and renal scar formation cannot be accurately determined in older children because VUR may improve or resolve over time. Therefore, older children without VUR at the time of research may have had VUR previously (CARVALHAL, ROCHA, MONTI, 2006, LIMA, 2007, ).


The suggestion for UTI may come from the clinical history and physical examination, however, the uroculture and that allows to confirm whether or not there is infection. Urine collection should be performed prior to administration of the antimicrobial agent of any kind. To avoid false-positive results, adequate urine collection should be done in childhood. Diagnosis and immediate treatment are fundamental in the long-term preventive framework of renal and bladder healing. For neonates and young neonates intravenous antibacterial agents are recommended. Exclusion of obstructive uropathies are recommended and subsequent vesico-ureteral reflux. Prophylaxis only in cases of high UTI susceptibility and high risk of kidney damage.


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CARVALHAL, G.F. ROCHA, L.C.A., MONTI, P.R. Urocultura e exame comum de urina: considerações sobre sua coleta e interpretação. Rev Ass Med RS. 2006.

CRAIG, J.C., SIMPSON, J.M., WILLIAMS, G.J., Antibiotic prophylaxis and recurrent urinary tract infection in children. N Engl J Med, 361, 2009

HANSSON, S. et al. Urinary tract infections in children below two years of age: a quality assurance project in Sweden. Swedish Pediatric Nephrology Association Acta Paediatr 1999.

JAKOBSSON B, ESBJORNER E, HANSSON S. Minimum incidence and diagnostic rate of first urinary tract infection. Pediatrics 1999.

KOCH, V. H.; ZUCCOLOTTO, S. M.C. Infecção do trato urinário: em busca das evidências. J. Pediatr. (Rio J.), Porto Alegre , v. 79, supl. 1, p. S97-S106, June 2003 . Available from <http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0021-75572003000700011&lng=en&nrm=iso>. Acesso em 12 de setembro de 2018. http://dx.doi.org/10.1590/S0021-75572003000700011.

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LO, D.S., RAGAZZI, S.L.B., GILIO, A.E., MARTINEZ, M.B. Infecção urinária em menores de 15 anos: etiologia e perfil de sensibilidade antimicrobiana em hospital geral de pediatria. Rev Paul Pediatr 2010.

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MACHADO, V.Q, MONTEIRO A, PEÇANHA A, et al. Slow transit constipation and lower urinary dysfunction. J Pediatr Urol. 2015;11(6): 357.e1-5. http://dx.doi.org/10.1016/j.jpurol.2015.05.032

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[1] Graduating in Medicine.

[2] Master’s degree in Biotechnology from the University of Ribeirão Preto – UNAERP; Specialist in Professional Education in the area of Health – Nursing by the Osvaldo Cruz Foundation – FIOCRUZ; Specialist in Surgical Center at the University of Ribeirão Preto – UNAERP; Graduation in Nursing and Obstetrics from the State University of Minas Gerais – UEMG; Medical Student at Universidade Brasil.

[3] Specialist in Dental Prosthesis at Faculdade São Leopoldo Mandic; Graduation in Dentistry from FOA- School of Dentistry of Araçatuba – UNESP; Medical Student at Universidade Brasil.

[4] Medical Residency in Pediatrics at Santa Casa de São Paulo/SP. Title of Specialist in Pediatrics by SBP.

Submitted: July, 2019.

Approved: August, 2019.

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