Urinary Tract Infections in Children

Dr. Rim El-Rifai

Consultant Paediatrician

QMHC

Outline of talk

Cases Introduction and definitions Evaluation of UTI Management Summary

7 year old girl

Initial referral to investigate secondary enuresis,

had a “positive urine for UTI” Main concern nocturnal enuresis Dysuria and dark offensive urine History of PUO’s for 2 days at a time No abnormal physical findings on

examination

investigations

Ultrasound scan KUB: Small capacity bladder, dilated distal ureter

and urothelial thickening in Lt renal pelvis and large left kidney on USS

DMSA: left Duplex with scarring of upper pole- has

patient had MCU?

3 weeks old girl

Initial presentation to A&E: vomiting Treated with IV AB’s 2 urine samples had mixed growth but > 100

WBC on SPA FH: brother had pyloric stenosis and UTI when 4

mo old TMP ran out after 2 weeks- did not get

prescription

Investigations

KUB USS normal Abdo. USS: Pyloric Stenosis MCUG and DMSA awaited

6 years old girl

Referred by GP for frequency and day time wetting at school

Urine showed no WBC but grew Enterococcus treated as UTI with oral TMP History: frequency and urgency but not unwell or

febrile Further urine dipstick and KUB normal On questioning: urine collected in make shift jar

at home

What is a UTI?

An inflammatory response of urothelium to bacterial invasion that is usually associated with bacteriuria and pyuria

i.e. MSU shows: WBC > 10 Pure growth of organisms > 107

Bacteriuria

Presence of bacteria in the urine in numbers exceeding the numbers caused by contamination from skin, urethra

Not a contaminant from the skin, vagina, prepuce

Collection technique sensitive May be asymptomatic

Pyuria

Presence of white blood cells (WBCs) in the urine

Generally indicative of an inflammation of the urothelium as a response to bacterial invasion

Sites of origin of UTI

Acute pyelonephritis: acute bacterial infection of the kidney

Fever, rigors Flank pain Bacteriuria and pyuria

Unwell child, usually febrile

Sites of origin of UTI

Bacterial Cystitis: Inflammation of the bladder Abrupt onset of dysuria Frequency Urgency Suprapubic pain

Non-bacterial cystitis: chemical

Sites of origin of UTI

Urethritis Inflammation of the urethra Symptoms difficult to differentiate from cystitis

Seen in girls with vulvovaginitis

UTI in Childhood

Features commonly non-specific

Associated with anatomical Urological

abnormalities

Difficulty in obtaining meaningful urine samples

Tendency to cause renal scarring

May lead to End Stage Renal Disease and

Hypertension in adult life

UTI in Childhood

Always regarded as complicated

Treatment very effective

Recurrence is frequent following first UTI:

40% in females,

32% in males

Childhood UTI : Epidemiology

Prevalence is age and sex dependent

Overall F > M

In 2-10% of children 2 mo – 2 yrs of age with

unexplained fevers

Incidence: age

UTI diagnosed in 3% of prepubertal girls,

and 1% boys

In children less than 1 year: M (2.7%) > F (0.7%)

Incidence: sex

Most male infections under 3 months 10 times more common in uncircumcised

males After first year 0.08% in boys 3-4% in girls until 6 years

Up to 8% of girls are affected by UTI

Access of bacteria

Haematogenous spread with bacteraemia

in first 12 weeks

After 3 months by ascending seeding

through urethra

Pathogens

Most common: E. Coli Other:

Proteus spp (in boys) Klebsiella Pseudomonas Enterococcus Staphylococcus epidermidis Staphylococcus aureus

Predisposing factors

Most commonly

Constipation Vesico-ureteric reflux Dysfunctional voiding- poor emptying Infected periurethral area Urinary stasis: PUJ, VUJ obstruction Ureteral duplication and ectopic ureters

Causes for recurrent UTI

Vesico-ureteric reflux Urinary stasis, constipation Infected periurethral area Infected atrophic kidney Ureteral duplication and ectopic ureters Infected urachal cysts, infected ureteral stump Foreign bodies Stones

Vesico-Ureteric Reflux

Vesico-ureteric Reflux

VUR demonstrated in 1-2% of healthy children

More prevalent in infants and young children

An intermittent phenomenon

Increased detection rate due to antenatal

screening

Can be provoked by elevated voiding pressures

Vesico-ureteric Reflux and UTI

Reported in 30-50% of children with UTI

A large number still present after their first

UTI

Reflux nephropathy is the cause for end-

stage renal failure in 3-25% of children

and 10-15% of adults

Evaluation of UTI

Presentation/Evaluation History in infants and toddlers:

Fever, irritability Poor weight gain (FTT) Smelly urine Abdominal Pain Dysuria, frequency, urgency Haematuria Enuresis and dysfunctional voiding Constipation, thread worm infection, sore vulva

Presentation/Evaluation

History in children: Fever Abdominal Pain (Flank/loin pain) Dysuria, frequency, urgency Haematuria “smelly urine” Enuresis and dysfunctional voiding Constipation, thread worm infection, sore vulva

History/ evaluation

History in Lower urinary tract infection: irritability Abdominal Pain Dysuria, frequency, urgency Haematuria “smelly urine” Enuresis and dysfunctional voiding Constipation, thread worm infection, sore vulva

History in enuresis/ incontinence Nocturnal symptoms:

Timing and onset of enuresis Frequency of wetting (wet nights/week) Times of wetting at night (one/several) Amount of urine passed (small/large)

Daytime symptoms: Urinary frequency (frequent/infrequent) Urgency and urge incontinence Quality of stream Complete emptying? Posturing (Vincent curtsey)

Evaluation

Physical examination: full examination including: Growth BP genitalia

Urine test imaging

Neuropathic Bladder

Sacral Agenesis

Laboratory assessment

Urine dipstick for Nitrites, Leukocytes

Urinalysis (clean catch sample)

Direct microscopy and gram staining

Culture and sensitivities

AAP and RCPCH guidelines for diagnosis of UTI in infants and young children

UTI should be ruled out in infants and

children assessed to be sufficiently ill to

require antibiotics treatment

Diagnosis of UTI requires a culture of

urine

Imaging

Urinary Tract Imaging

Plain Abdominal x-ray Ultrasound- any age Micturating cystourethrogram < 1 year Nuclear Imaging- any age IVU CT scan

Ultrasound

Renal size and position Scars, corticomedullary differentiation, cysts,

masses, calcification, calculi Pelvis and calyceal size and appearance

Pelvis-calyceal dilatation, urothelial thickening Ureters

Dilatation, urothelial thickening, calculi Bladder

outline, wall thickness, volume, residual volume

DMSA

Renal cortical morphology

Scars

Overall function

Differential function

No information on VUR

MAG 3

Quantify renal excretory function

Flow imaging

PUJ obstruction

Indirect cystogram

MCUG: Bilateral VUR

DMSA: Left renal scarring

Imaging of urinary tract after first febrile UTI in Young children :

USS during acute illness of limited value

MCUG useful in young age group where

AB prophylaxis considered to reduce re-

infection and renal scarring

DMSA at presentation and 6 months later

identifies renal scarring

Pittsburgh SM N E J M, Jan 2003

Complications of UTI

Complications

Acute: Systemic illness, sepsis, renal abscess

Short term: Renal scarring, recurrence of UTI

Long term: Hypertension End-stage renal disease (overall 0.5%-5% of

ESRD on dialysis have reflux nephropathy)

Renal scarring and VUR: International Reflux Study in Children

5 yr follow up 302 patients (10 yrs in 5/8 European centres)- serial IVU and DMSA

Grade III, IV, V VUR and symptomatic UTI Medical vs Surgical treatment of VUR New scars in 21 surgical and 19 medical New scars mostly in children < 5years old New scars more frequent in Grade IV New scars in 2 females > 5 years

Olbing H et al, Ped Nephrol, Oct 2003

Complications of UTI in Children

Hypertension

Pyelonephritic scarring is the most common

cause for hypertension in childhood

Prevalence of hypertension independent of

the degree of scarring

Treatment

E. Coli Resistance trends

Ampicillin 39-45%

Trimethoprim-sulfamethoxazole 14-31%

Nitrofurantoin 1.8-16%

Fluoroquinolones (Ciprofloxacin) 0.7-10% Mazzuli T, J Urol 2002

Drugs for Treatment

TMP 4 mg/kg BD for 7-10 days Cephalosporins (Cefuroxime, Cephalexin) Gentamicin Ciprofloxacin Ampicillin? Nitrofurantoin (over 3 mon)?

Duration of treatment

Uncomplicated UTI: > 5 days is associated with higher cure rates

Tran D et al, meta-analysis of 1279 patients J Pediatr 2001

In Children < 2years of age: 7-14 days AAP, Pediatrics 1999 and RCPCH appraisal

Drugs for prophylaxis

Trimethoprim 2 mg/kg nocte

Cephalexin 12.5 mg/kg (up to 125 mg) nocte

Nitrofurantoin (over 3 mon) 1 mg/kg nocte

Cessation of prophylaxis

By age 4 years When urinary continence achieved and

infection free Safe in patients in whom VUR fails to

resolve Thompson et al J Urol 2001

Surgery

Anti-reflux open procedures: 95-98% success Endoscopic subureteric injections: 75-90% success

Teflon- no longer approved by FDA (success 60-84%) Collagen Macroplastique Deflux (Dextranomer/hyaluronic acid copolymer) 70% success

When? Breakthrough UTI Persistence of VUR Parental preference

Treatment: Bladder Retraining

Aims at increasing functional bladder capacity

and reduction in residual volume

2-3 hourly voiding

Double voiding

Increasing retention capacity

Isolated success in continence rate 35%

Prevention

Breast feeding

Lactoferrin and oligosaccharides act as

analogues for microbial receptors

Prevents mucosal attachment

Lactoferrin can kill bacteria, viruses and fungi

Prevention

Healthy voiding pattern

Avoidance of constipation

Avoidance of local colonization

Circumcision?

Cranberry juice?

Probiotics?

Points to remember

Accurate diagnosis of UTI

Low threshold to investigate in younger children

(<4 years)

Appropriate treatment of acute events

Consider other problems when managing UTI

Points to remember

The need to recognize the relationship between:

VUR Recurrent UTI’s Voiding dysfunction Renal scarring

Treatment should target each factor