Urinary Tract Infections

Dr. Kalpana MallaMD Pediatrics

Manipal Teaching Hospital

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UTI

• Definition:- Invasion & multiplication of micro-

organisms in the urinary system– any component of the urinary tract

including• Urethritis• Cystitis• Pyelonephritis

Classification

UTI - Classification:-

A. On the basis of underlying defect simple complicatedB. Based on symptoms Symptomatic UTI Asymptomatic UTI

Classification C. On the basis of region

involved - Upper UTI -

pyelonephritis

- Lower UTI – Cystitis - Urethritis

Incidence:-

• Newborn : M=F Hematogenous spread Cong. anomalies in males• >1 yr : F>M Ascending infection**Overall 1% boys & 3 % girls have UTI in 1st

decade

Causes of UTI

Etiology - Microorganisms

• Gram negative bacteria• - Escherichia coli (80 %- 90 %) • - Klebsiella• - Proteus (30%)• Gram positive bacteria• - Enterobacter• - Citrobacter. • - Staph saprophyticus• - Group B streptococcus - H. Influenza• - Staph. Aureus

A. Bacteria:-

Etiology - Less common B. Virus:- Ebstein Barr Adenovirus enteroviruses Coxsackie viruses echoviruses C) Fungus - Candida spp., Aspergillus spp. Cryptococcus neoformans

D) Parasite

Risk Factors

1.Host Factors:- a) Stasis -Urinary obstruction  - infrequent & incomplete voiding - Constipation - Obstruction to flow-PUV,PUJ obs,stones,ureterocele - Neurogenic bladder - Vesicoureteral reflux 

Host Factors:-

b) Instrumentationc) Malnutrition d) Age/ Sexe )Uncircumcised boysf )Race/ethnicity g )Genetic factorsh) Length of urethrai) Urine itself j) DM

Risk Factors

2. Agent-organism3. Size of inoculum- small/large

PATHOGENESIS

• Ascending infection most UTI beyond the newborn period

• Descending infection 4 - 9 percent of children

with UTI are bacteremic

Clinical features

Presentations

< 2 month - nonspecific symptoms and signs – fever , Jaundice

2month -1 year:- Fever/Hypothermia Vomiting, Diarrhea Sepsis Irritability Lethargy Malodorous urine

Presentations

1-5 years:-Abdominal pain- Flank /back/ Supra pubic - Vomiting ,diarrhea - Constipation - Abnormal voiding - Urgency, urinary incontinence,

dysuria

1-5 years

- Malodorous Urine - Fever/febrile convulsion

- Failure to thrive

Presentations

>5years:-Dysuria Frequency Urgency Abdominal discomfort Fever Malodorous urine

Physical examinations

• Temperature• Pallor• Anthropometry• Blood pressure• Tenderness-Lower abdomen• Renal angle• Renal mass• Palpable bladder

Physical examinations

• Fecal mass• Signs of valvitis• Spine• Lower limb reflexes• Associated with UTI-Prune belly syndrome Anorectal anomalies

Localizing symptoms:

Symptoms of urethritis:• Dysuria• Reluctance to void• Perineal discomfort• Vaginal irritation and erythema in

girls• In older boys, urethral discharge• In adolescent girls associated with

PID symptoms

Features of cystitis:• Afebrile usually• Frequency• Enuresis• Dysuria• Reluctance to void

Localizing symptoms:

Features of pyelonephritis:• Fever and systemic signs • Older children –Flank pain or abdominal pain

• Younger children–Fever, irritability, vomiting, poor

feeding

Localizing symptoms:

LABORATORY EVALUATION

DipstickMicroscopy

Culture & sensitivity

Investigations

Methods of urine collection• Clean catch or midstream sample• Supra pubic aspiration –infancy• Urinary bag sample –small children• Catheter specimen –Severely ill

LABORATORY EVALUATION 

Urine dipstick

88 % sensitive

• Leukocytes• Protein• Red blood cells • Leukocyte esterase• Nitrite

LABORATORY EVALUATION 

Microscopic exam

• Bacteria: bacteriuria is the presence of any bacteria per hpf.

• Gram stain

Routine Microscopic Examination

• Color-Hazy• Smell- malodorous• White Blood Cells: pyuria is defined as ≥5

WBC/PHF in centrifused or ≥10 WBC/mm3 in an uncentrifuged sample

• Bacteria: bacteriuria is the presence of any bacteria per hpf. - Gram stain

Routine Microscopic Examination

• RBC >5 /HPF• RBC+WBC casts+• Albumin –Trace to +Urine C/S- gold standard - should be processed as

soon as possible after collection

LABORATORY EVALUATION

Urine culture • Midstream clean catch > 10⁵ colony forming units (girls) > 104 CFU (boys)• Catheterization 10⁵ CFU• Supra pubic aspiration any growth

LABORATORY EVALUATION

• Investigate the fever – CBC, CRP • Serum creatinine• Blood culture — Bacteremia occurs in 4-

9 % of infants with UTI

• Lumbar puncture — Infants <1 month of age with fever and a positive urinalysis; approximately 1 % of infants with UTI also have meningitis

Other laboratory tests

Imaging studies

1.Radiological – MCU IVP X-ray KUB2. Nuclear- USG DMSA scan DTPA scan MAG scan

Renal scans

• DMSA renal scan – anatomy of kidney (Scarring)

• DTPA renal scan – Excretory function ,filtration function of kidney

• MAG 3 with lasix renal scan – Obstruction at the ureterovesical junction - quantitative information regarding kidney function and drainage , assesses the degree of blockage

Principle of management

1. Treatment of acute infection2. Prevention of further infection3. Adequate investigation4. Arrangement of further treatment5. Follow up - Prevention of recurrence

and long-term complications

MANAGEMENT

Indication for hospitalize:•  Age <2 months • Sepsis or potential bacteremia • Immunocompromised patient • Vomiting or inability to tolerate oral

medication • Lack of adequate outpatient follow-up• Failure to respond to outpatient therapy

Choice & route of Treatment

Depends on – Age Severity of illness

Choice of agent: provide adequate coverage for E. coli.

ANTIBIOTIC THERAPY:

• Newborn + Infants Inj ampicillin + Inj. Gentamycin-14 days

• Older children:- Oral – Co-timoxazole cephalosprins Nalidixic acid amoxicillin-clavulanate• Parenteral therapy: Ampicillin or Third- or

fourth-generation cephalosporins and aminoglycosides - first-line agents for empiric treatment of UTI in children.

MANAGEMENT

ANTIBIOTIC THERAPY• Duration of therapy:  7-14 days • Response to therapy: Clinical response Repeat urine culture 

Indications for further investigations:

1. Girls younger than 3 years with a first UTI

2. Boys of any age with a first UTI 3. Children of any age with a febrile UTI 4. Children with recurrent UTI5. First UTI in a child of any age with a

family history of renal disease, abnormal voiding pattern, poor growth, hypertension

Prevention

1. General measures:-• Fluid intake• Complete and periodic voiding• Vioding at bed time• Perineal hyiene• Treatment of worms• Prevention of constipation• Avoid catheterization

Prevention

• Early treatment of cong anomalies• Circumcision2. Low dose chemoprophylaxis - UTI until radiological evaluation is complete - Recurrent UTI - VUR grade I- III - Post operative-PUJ,VUR IV & V, PUV

Prevention

- Chronic cystitis - Neurogenic ladderCommonly used drugs for prophylaxis:-• Co-trimoxazole-2mg/kg/d• Nalidixic acid-12.5mg/Kg/d• Nitrofurantoin -1mg/kg/d

Follow up

1. Clinical- During the year following infection 1 year after starting prophylaxis height, Blood pressure –recorded2. Urine C/S- 3 monthly-infancy Fever & symptoms –older children3.RFT 4. Imaging –when neded

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