PEDIATRIC UTI

PREPARED

BY

ASOGWA INNOCENT KINGSLEY

ML-508

DEFINITION Infection of the urinary tract is

identified by growth of a significant number of organisms of a single species in the urine, in the presence of symptoms.

Recurrent UTI, defined as the recurrence of symptoms with significant bacteriuria in patients who have recovered clinically following treatment, is common in girls.

PREVALENCE UTI is a common bacterial infection in infants and

children. The risk of having a UTI before the age of 14 yrs

-1- 3% in boys

- 3-10% in girls . In girls, the first UTI usually occurs by the age of 5

yr, with peaks during infancy and toilet training. In boys, most UTIs occur during the 1st yr of life;

more common in uncircumcised boys. During the 1st yr of life,

-M : F ratio is 2.8–5.4 : 1. Beyond 1–2 yr,

-M : F ratio of 1 : 10.

RISK FACTORS FOR URINARY TRACT INFECTION:

Anatomic risk factorsVesiculoureteral reflux (VUR)

More common in girlsObstructionPosterior urethral valves

BoysVoiding dysfunctionBladder diverticulum

RISK FACTORS FOR URINARY TRACT INFECTION:

Associated risk factorsConstipationEncopresis(Involuntary defecation

not attributable to physical defects or illness.)

Bladder instabilityInfrequent voiding

Unsubstantiated risks BathingBack-to-front wiping

ETIOLOGY The Culprits

◦ Escherichia Coli◦ Enterococcus◦ P. aeruginosa◦ Klebsiella sp.◦ Proteus sp.◦ Enterobacter sp.◦ Coag-negative staph◦ Staph aureus◦ Candida sp.

BACTERIAL FACTORS Virulence Factors

◦ Cell Wall Antigens◦ Serum Resistance◦ Hemolytic Capability◦ Growth Dynamics◦ Iron Scavenging

Adherence Factors◦ P Fimbriae◦ Type 1 Fimbriae◦ DR Fimbriae

HOST DEFENSE FACTORS Urine pH / Vaginal pH

Local IgA Antibodies

Voiding Mechanics

Ascending Route of UTI°Bacterial Colonization°Migration to Periurethral Region°Migration into Bladder°Growth in Urine°Bacterial Ascent to Kidney°Colonization of Renal Medulla°Focal Abscess Formation°Bacteremia°Kidney Re-infection

PATHOGENESIS - UTI

CLINICAL MANIFESTATIONSThe 3 basic forms of UTI

1. Pyelonephritis2. Cystitis3. Asymptomatic bacteriuria

PYELONEPHRITIS Clinical pyelonephritis is characterized by

any or all of the following: - abdominal or flank pain, - fever, - malaise, nausea, vomiting, and, - occasionally, diarrhoea. In newborns show nonspecific symptoms : - poor feeding, irritability, and weight loss. Pyelonephritis is the most common serious

bacterial infection in infants <2 yrs of age who have fever without a focus .

OUTCOMES OF PYELONEPHRITIS

Acute lobar nephronia (acute lobar nephritis) is a localized renal bacterial infection involving >1 lobe that represents either a complication of pyelonephritis or an early stage in the development of a renal abscess.

Renal abscess may occur following a pyelonephritis or may be secondary to a primary bacteremia (S. aureus).

Perinephric abscesses may be secondary to contiguous infection in the perirenal area (e.g., vertebral osteomyelitis, psoas abscess) or pyelonephritis that dissects to the renal capsule.

XANTHOGRANULOMATOUS PYELONEPHRITIS

Xanthogranulomatous pyelonephritis is a rare type of renal infection characterized by granulomatous inflammation with giant cells and foamy histiocytes.

It may present clinically as a renal mass or an acute or chronic infection.

Renal calculi, obstruction, and infection with Proteus spp. or E. coli contribute to the development of this lesion, which usually requires total or partial nephrectomy.

CYSTITIS It indicates that there is bladder involvement. Symptoms include :• dysuria, • urgency, • frequency, • suprapubic pain,• incontinence, and• malodorous urine. Cystitis does not cause fever and does not

result in renal injury.

ASYMPTOMATIC BACTERIURIA

It refers to a condition that results in a positive urine culture without any manifestations of infection.

It is most common in girls. The incidence is 1–2% in

preschool and school-age girls and 0.03% in boys. The incidence declines with increasing age.

Rapid evaluation and treatment of UTI is important to prevent renal parenchymal damage and renal scarring that can cause hypertension and progressive renal damage.

Diagnosis◦ Culture Methods◦ Screening Tests◦ Anatomic / Functional Evaluation

Treatment◦ Age of Patient◦ Severity of Infection◦ Prior History of UTI

MANAGEMENT - UTI

Microscopic Analysis

Urine Dipstick Analysis◦ Sensitivity 80-90% / Specificity 60-

98%◦ Leukocyte Esterase◦ Nitrites

First Voided Urine Best Dietary nitrates

SCREENING TESTS

Clean Voided Specimen◦80% Accuracy

Bagged SpecimenCatheterized SpecimenSuprapubic Aspiration

CULTURE METHODS

SPECIMEN COLLECTION Newborns & Infants

◦ Bagged Specimens◦ Suprapubic Aspiration◦ Urethral Catheterization

Toddlers◦ Bagged Specimens◦ Clean Void◦ Urethral Catheterization

School Age Children◦ Midstream Clean Catch

- *Midstream Clean Catch Specimen <10,000 CFU Probable

Contaminant >100,000 CFU Significant Colony

Count

Enteric Gram Negative Bacteria

QUANTITATIVE URINE CULTURE

ANATOMIC / FUNCTIONAL EVALUATION Goals

◦ Assess risk of Damage

◦ Assess Presence of Damage

◦ Identify Complicating Factors

EVAUATION OF UTI

Physical Exam Imaging Studies

◦ When to Evaluate?◦ How To Evaluate?◦ RUS◦ IVP◦ DMSA Scan◦ Cystography

RNC VCUG

Girls

Initial Studies◦ USN◦ VCUG

Follow-up Studies◦ USN◦ VCUG

Boys

Initial Studies◦ USN◦ VCUG

Follow-up Studies◦ USN◦ VCUG

UTI IMAGING STUDIES

UTI - ULTRASOUND

2-3 % Yield Obstructive Uropathy

Bellman, 1995

UTI - VOIDING STUDY VCUG For 1st Study Pyelonephritis

Associated With Vesico-Ureteral Reflux

50%

Bellman, 1995

TREATMENTThe patient’s age, features

suggesting toxicity and dehydration, ability to retain oral intake and the likelihood of compliance with medication(s) help in deciding the need for hospitalization.

Therapy should be prompt to reduce the morbidity of infection, minimize renal damage and subsequent complications.

TREATMENT Children less than 3 months of age and those

with complicated UTI should be hospitalized and treated with parenteral antibiotics.

The choice of antibiotic should be guided by local sensitivity patterns.

A third generation cephalosporin is preferred. Therapy with a single daily dose of an

aminoglycoside may be used in children with normal renal function.

Intravenous therapy is given for the first 2-3 days followed by oral antibiotics once the clinical condition improves.

TREATMENTChildren with simple UTI and those above 3 months of age are treated with oral antibiotics.

With adequate therapy, there is resolution of fever and reduction of symptoms by 48-72 hours.

Failure to respond may be due to presence of resistant pathogens, complicating factors or noncompliance; these patients require reevaluation.

TREATMENT The duration of therapy -14 days for infants and children with

complicated UTI - 7-10 days for uncomplicated UTI. Adolescents with cystitis may be treated with

shorter duration of antibiotics, lasting 3 days. Following the treatment of the UTI,

prophylactic antibiotic therapy is initiated in children below 1 year of age, until appropriate imaging of the urinary tract is completed.

EVALUATION AFTER THE FIRST UTI The aim of investigations is to identify patients at high

risk of renal damage, chiefly those below one year of age, and those with VUR or urinary tract obstruction.

Evaluation includes ultrasonography, DMSA renal scan and micturating cystourethrography (MCU) performed .

An ultrasonogram provides information on kidney size, number and location, presence of hydronephrosis, urinary bladder anomalies and post-void residual urine.

DMSA scintigraphy is a sensitive technique for detecting renal parenchymal infection and cortical scarring.

MCU detects VUR and provides anatomical details regarding the bladder and the urethra.

EVALUATION AFTER THE FIRST UTI

EVALUATION AFTER THE FIRST UTI

Ultrasonography should be done soon after the diagnosis of UTI.

The MCU is recommended 2-3 weeks later.

The DMSA scan is carried out 2-3 months after treatment.

PREVENTION OF RECURRENT UTI

General Measures: Adequate fluid intake and frequent voiding constipation should be avoided In children with VUR who are toilet trained,

regular and volitional low pressure voiding with complete bladder emptying is encouraged.

Double voiding ensures emptying of the bladder of post void residual urine.

Circumcision reduces the risk of recurrent UTI in infant boys, and might therefore have benefits in patients with high grade reflux.

ANTIBIOTIC PROPHYLAXIS

Long-term, low dose, antibacterial prophylaxis is used to prevent recurrent, febrile UTI.

The antibiotic used should be effective, non-toxic with few side effects and should not alter the growth of commensals or induce bacterial resistance .

ANTIBIOTIC PROPHYLAXIS

Antibiotic prophylaxis is recommended for patients with

(i) UTI below 1-yr of age, while awaitingimaging studies, (ii) VUR (iii)frequent febrile UTI (3 or more

episodes in a year) even if the urinary tract is normal.

VESICOURETERIC REFLUX•VUR is a bladder valve defect that allows urine to reflux from the bladder through one or both ureters and up to the Kidneys.

•Febrile urinary tract infection (UTI) is the defining Symptom.

VUR is seen in 40-50% infants and 30-50% children with UTI, and resolves with age.

Its severity is graded using the International Study Classification from grade I to V, based on the appearance of the urinary tract on MCU.

The presence of moderate to severe VUR, particularly if bilateral, is an important risk factor for pyelonephritis and renal scarring, with subsequent risk of hypertension, albuminuria and progressive kidney disease.

The risk of scarring is highest in the first year of life

VUR GRADES

SCREENING OF SIBLINGS AND OFFSPRING:

Reflux is inherited in an autosomal dominant manner with incomplete penetrance; 27% siblings and 35% offspring of patients show VUR.

Ultrasonography is recommended to screen for the presence of reflux.

Further imaging is required if ultrasonography is abnormal