Recurrent Urinary Tract Infections

Dr. Mehul A. ShahM.D.(Ped.), DCH (Bom.), M.D.(USA)

Diplomate of Am Board of Ped. Nephrology

Consultant Pediatric Nephrologist

Rainbow Children’s Hospital

Hyderabad

“A lecture is the transfer of information from the lecturer’s notes to the student’s notes without passing thru the brains of either”

“Conference is the confusion of one man multiplied by the number present”

TOI

UTI: Definition

UTI is the common term for a group of conditions in which there is growth of bacteria within the urinary tract

Bacteriuria is the presence of bacteria in the urine

Growth of 100,000 colony forming units in freshly voided sample of urine - cutoff between UTI and contamination

UTI: Epidemiology

3-5% girls and 1-2% boys

First UTI - < 1 year

Recurrence rate – 40% in 1 year and 50% in 5 years

VUR – 30-65 %

Obstructive malformations – 10%

UTI: Clinical Features

Depends upon the age of the child and level of infection

Young children (less than 2 years of age)

Nonspecific symptoms- fever, irritability, vomiting, diarrhoea, not gaining weight

Older children- burning sensation, increased frequency, bedwetting (new onset), backache

Upper UTI- high fever, vomiting, abd. pain

UTI: Diagnosis

Depends upon Urine culture

No positive findings on clinical exam

Positive findings on CUE – pyuria and positive nitrite test

Pyuria is WBC > 10 cells/microL, and is present in 85% of symptomatic children.

Pyuria is NOT SPECIFIC for UTI

Positive nitrite test – 50% of cases

Urine for general exam in NOT adequate for diagnosis

UTI: Diagnosis

Method of collection Quantitative culture- UTI present

Suprapubic aspiration Growth of urinary pathogens in any number

Catheterization in females or midstream void in circumcised males

Febrile infants or children usually have >/= 50 x 103 CFU/mL of a single urinary pathogen

Midstream clean void Symptomatic patients: usually >/= 105 CFU/mL of a single urinary tract pathogen

Bag specimen Useful only if the culture is negative

UTI: Treatment

Initial treatment may include Bactrim (8mg/kg/day of TMP in BID),Cefixime (8mg/kg/day), Amox-clavulinic acid (20-30mg/kg/day in BID)Nalidixic acid (40-50 mg/kg/day in TID)

IV treatment is indicated in infants < 6 months of age or in children with persistent vomiting

Hydration, hygiene, treating constipation

UTI

Does the treatment of UTI stop here?

Answer - NO

Question to be answered- Why did the child get UTI?

UTI: Protective Factors

Urine is an excellent medium for bacterial growth.

The defense mechanisms include- Regular bladder emptying, which flushes out any bacteria which may have ascended up the urethra

That is why our urinary bladder is NOT a big tank and we do not pass urine ONCE a day- Killing of bacteria by bladder wall lining- Antibacterial properties of urine

UTI: Predisposing Factors

Any factor which causes retention of urine predisposes to UTI

In children, the most common causes of urinary retention are:

-Vesico-Ureteral Reflux (VUR); 40%

-Obstruction in plumbing system; 10%

-Bladder dysfunction, which could be due to neurogenic problem or Dysfunctional voiding syndrome

Bacterial properties - adhesins, fimbriae, hemolysins, etc. can cause Upper UTI even in absence of Reflux.

UTI: Complications

Recurrent UTI’s -increased discomfort to child -anxieties in parents -increased medical costs

Reflux Nephropathy, in 30% of patients with VUR-kidney failure (10%), dialysis and kidney transplant -Hypertension, in 10-30% of cases with RN

Hypertension (High BP)-paralysis-heart failure-kidney failure

UTI: Complications

Renal scarring-

VURHost susceptibilityUrinary tract obstructionHost inflammatory responseTherapeutic delay

VUR & Reflux Nephropathy

- 30-60% of children with symptomatic UTI have Reflux

- 30% of patients with VUR will have RN (scarring)- Scarring is predominantly seen at both poles in

children < 5 years of age- Incidence of HTN is 5-30% with scarring- Conversely, 30% of patient’s with HTN have RN

as their etiology

- 10% of ESRD in children is due to RN

Recurrent UTI

1) Anatomic abnormalities

2) Vesico-ureteric reflux (VUR)

3) Dysfunctional voiding syndrome

4) Hypercalciuria

Vesico-Ureteric Reflux

VUR & Reflux Nephropathy

International Classification of Vesico-Ureteral Reflux.

VUR & RN: Diagnosis1) Radiocontrast MCUG To be done the first time when evaluating any child below

5 years to look for associated anatomic abnormalities, bladder trabeculation and urethral obstruction in boys

Sedation or GA to be avoided False negative in about 20% of cases

2) Direct Radionuclide Cystography (DRC) Advantages- much lower radiation exposure to gonads

(100-200 fold lower) and it is more sensitive

VUR: Treatment

A} Medical:

Cornerstone in initial management, based on scientific data from Lenaghan and Smellie in mid 1970’s

Continuous antibacterial prophylaxis, either with Bactrim (2 mg/kg of TMP as a single dose at bedtime) Nitrofurantoin (2-3 mg/kg) Nalidixic acid (10 mg/kg in bid doses) Cephalexin (10mg/kg in bid doses) in infants less than 6 months of

age Prophylaxis is continued until reflux resolves or until the

risk of reflux is considered to be low (6 years)

VUR: Treatment

B} Surgical:

Open surgical management to create 4-5:1 ratio of length of intramural urete to ureter diameter (Ureteric reimplantation)

>95% success rate and <2% risk of obstruction as a complication

Endoscopic repair, (STING) subtrigonal injection of PTFE or collagen, success rate – 70%, often needs to be redone and long term safety of Teflon not established.

Dysfunctional voiding syndrome

“Sorely neglected in most recommended protocols for evaluating urinary infection is an investigation for micturition disturbances which may be responsible for the infections.Treatment of these conditions may actually prevent recurrence of infection. Controversy surrounding the proper imaging evaluation for UTI appears to be misdirected. Instead of arguing about which imaging study should be performed or which child with a first UTI should have a cystogram, our patients might be better served it we wondered why traditional protocols for evaluating UTI deal only with imaging studies.”

Koff SA, Pediatr Nephrology 1991;5:398-400

Dysfunctional voiding syndrome

More frequently a cause of recurrent UTI in older children, in absence of anatomic abnormalities or VURAcquired condition, due to imbalance between bladder contraction and sphincter function. Often due to “lazy” attitudeGirls > Boys, 2-10 years of agepass urine infrequently or frequency, urgency, “holding” posturessecondary incontinence of urineoften associated with constipation

Dysfunctional voiding

DiagnosisAge group- 2-10 yearsUsually based on typical history- incomplete and

infrequent bladder emptying, secondary daytime enuresis, posturing etc

H/o constipation (in 80%)Residual urine on USG (may be helpful) Investigations (rarely needed)- MCUG, and

urodynamic study

Dysfunctional voiding syndrome

Treatment Voiding schedule so that the child passes urine every 2-3

hours to retrain the urinary bladder. Double or Triple voiding Avoid ‘holding’ urine Aggressive treatment of constipation Positive re-inforcement technique Anticholinergics (Oxybutinin) may be required in some

cases after Urodynamic studies. Usually takes 3-6 months for bladder re-training.

Hypercalciuria

Hypercalciura

An important but less common cause of UTI

To be considered in a child with normal MCUG and recurrent UTI with a background family h/o renal stones

Hypercalciuria can cause UTI, recurrent abdominal pain, hematuria, lower tract symptoms, and renal stones

Spot urine calcium to creatinine ratio of <0.18 in children > 18 months age

Treatment is simple – dietary modification and alkylating agents, thiazides

UTI: Work-up

Whom?

Children less than 5 years of age, with first UTI – USG & MCUG

Boys with symptomatic UTI

Older girls with recurrent UTI

UTI: Work-up

Why?

Non-specific s/s in young infants Renal scarring may occur even after one episode of UTI 50% risk of recurrence in first 6 months after the initial

episode of UTI Incidence of renal scarring is higher in children with

recurrent UTI’s

Risk of renal scarring is maximum in the first 5 years of life

UTI: Work-up

What?

USG of kidney, ureter and bladder

MCUG (Micturiting Cysto Urethro Gram)

Thorough voiding and stooling history to rule out Dysfunctional elimination syndrome

Other investigations as needed like IVP, DTPA, DMSA renal scan, spot U Ca / creat etc.

UTI: prophylaxis

For whom?

VUR Anatomic abnormalities Dysfunctional voiding Recurrent UTI’s In children less than 2 years of age, in

absence of radiological abnormalities

UTI: prophylaxis

Which drug?

Bactrim (2 mg/kg of TMP as a single dose at bedtime)

Nitrofurantoin (2-3 mg/kg)Nalidixic acid (10 mg/kg in bid doses)Cephalexin (10mg/kg in bid doses) in infants

less than 6 months of age

UTI: prophylaxis

How long?

Until the risk of scarring is minimalUsually up to 6 years of agePrimary problem is resolved

UTI: Prevention

Other measures-

Hygiene

Circumcission

Plenty of liquids

Complete and regular bladder emptying

Treat constipation

Case 1

• 1-1/2 years, boy with recurrent episodes of moderate fever since 3 months of age

• Diagnosed to have UTI at 1-1/2 years of age• Renal USG was reported normal• Should MCUG be performed ?• Renal scan - Result ?

Case 2

7 years, girl with failure to thrive and history s/o UTI

Weight of 14 kgs, height of 95 cms

BP – 118 / 80, 126 / 82

Renal USG – reported normal

MCUG – Bilateral grade 3 VUR

DMSA scan – bilateral renal scarring (R>L)

After prophylaxis and anti-hypertensive therapy, better with weight gain of 2 kg in 3 months

Case 3

3 years old girl, with recurrent UTI’s since 1 year of age, with increased frequency of infections over the past 6 months

Classical history of dysfunctional elimination syndrome

Renal USG – normal

DRCG

DMSA scan – No scarring

VUR and Dysfunctional voidingPre-treatment

VUR and Dysfunctional Voiding-Post-treatment

Message

Think of UTI in an infant with fever without focus of infection

Diagnose UTI with a urine culture

Treat UTI’s promptly to minimize risk of scarring

Investigate EVERY child with UTI with at-least a renal USG AND MCUG

Normal USG does-not rule out VUR

Dysfunctional voiding is an important risk factor for recurrent UTI in an older child

Once a scar is formed, it will stay for ever and then the child has a risk for developing HTN and ESRD

Message

Think

Prompt therapy

Investigate

Prevent scars

(HTN & ESRD)

Prevent Renal Scars – Prevent Hypertension, and ESRD