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