Urinary Tract InfectionSeptember 2014

Pediatric Continuity Clinic CurriculumCreated by: Michelle Y. Spencer, MD

Objectives

• Describe the association of urinary tract infections (UTIs) and unexplained fever in infants

• Discuss the management of suspected UTI

• Review the use of radiologic studies to diagnose vesicoureteral reflux (VUR)

Case #1A 3 m.o. male presents to acute clinic with 2 day history of tactile fever, frequent emesis and poor feeding. On exam, baby is fussy with temperature 38.4, HR 115 and BP 94/59 and no other significant abnormalities.

Discussion Questions:• What is the next step in evaluating this patient

with fever?

• What are the indications for hospitalization?

What is the next step in evaluating this patient with fever?

• Obtain urinalysis– The prevalence of UTI in febrile infants who have no

obvious source is about 7-9% in those < 3 m.o. regardless of sex

– It decreases to 2% for males > 3 m.o. and females > 12 m.o.

• The “gold standard” for diagnosing UTI is the urine culture obtained by suprapubic aspiration, urethral catheterization, a ‘clean catch’ midstream specimen and bag collection (least preferable).

Interpreting the urine dipstick• Nitrite test: presence of gram-negative bacteria

in urine that reduce dietary nitrate to nitrite– 37% sensitive and 100% specific. Positive predictive

value 90% and negative predictive value 100%• Leukocyte esterase test: presence of leukocytes

(best performed on a fresh specimen)– 73% sensitive and specific. Positive predictive value

34% and negative predictive value 95%– Presence may be related to vaginal secretions,

dehydration, interstitial nephritis, etc.

General Criteria to Diagnose UTI• Suprapubic Aspiration– Any growth of gram negative bacilli or > 1,000

units/ml of gram positive cocci• Urethral Catheterization– Greater than 50,000 colony forming units/ml for

circumcised/uncircumcised males and all females• Midstream Clean Catch– Greater than 100,000 colony forming units/ml.

These values pertain to pure, one pathogen colony growth

What are the indications for hospitalization?

• Infants < 3 months old should be hospitalized to receive IV fluids and antibiotics. – NOTE: Each hospital might have different protocol

• Indications for hospitalization for older infants through adolescents: – Dehydration– Inability to take oral fluids– Ill appearing infant or child– Patients who have chronic diseases: sickle cell,

diabetes, cystic fibrosis or urinary tract abnormalities– Presence of perinephric abscess

Flow Chart for Evaluation & Management of UTI in Older Children and Adolescents

Case #2A 5 y.o. female presents with 3 day history of fever and dysuria. Clean catch urine dipstick reveals spec grav 1.015, pH 6.0, positive nitrites, bacteria and leukocyte esterase.

Discussion Questions:• What is the most likely organism causing this

patient’s symptoms?

• What is the most appropriate next step in management?

What is the most likely organism causing this patient’s symptoms?

• Escherichia coli (E. coli) accounts for up to 70% of urinary tract infections

• Other bacterial pathogens:– Pseudomonas aeruginosa (nonenteric gram negative)– Enterococcus faecalis– Klebsiella pneumoniae– Group B strep (predominately in neonates)– Proteus mirabilis (boys > 1 y.o. and associated with

renal calculi)– Coag negative Staphylococcus

Other pathogens causing UTI

• Fungal UTI caused by Candida albicans – Associated with instrumentation or the urinary

tract

• Viral UTI caused by Adenovirus and BK virus (hemorrhagic cystitis)

What is the most appropriate next step in management?

1. Send urine culture2. Start antibiotic therapy

o Timely appropriate treatment is helpful in preventing renal injury that may lead to scarring

Cystitis– Most cases 3-7 day course of antibiotics

Pyelonephritis– Start 10 day course of appropriate oral or IV antibiotic for

initial treatment– In cases of prolonged fever or renal abscess consider 14 days

3. Obtain radiologic imaging

Appropriate Antibiotic Therapy• Uncomplicated Cystitis: Choice of agents -Cefixime(Suprax) -Cefdinir(Omnicef) -Ceftibuten (Cedax)

- Ciprofloxacin- Nitrofuratoin

• There is increasing resistance to Amoxicillin, Ampicillin, Trimethoprim-sulfamethoxazole (> 2 months of age), Amoxicillin-clavulanate, Cephalexin

• Uncomplicated Acute Pyelonephritis– Similar to cystitis Ciprofloxacin 500 mg BID or extended release 1000

mg once dailyAdjust antibiotic as indicated after bacterial sensitivity available.

Radiologic Imaging• Fluoroscopic VCUG is the gold standard for

diagnosing VUR– VCUG should be done after infected urine becomes

sterile or after completion of full course of antibiotics, though studies have shown that it could be done after 48-72 hours after initiation of antibiotics

• Renal ultrasound is safe and fast way of detecting congenital renal urinary tract anomalies that may be associated with UTI and VUR– Can be obtained within 2-4 weeks of initial UTI

Indications for Ultrasonography

• Patients < 2 years of age with a first febrile UTI

• Patients of any age with recurrent febrile UTIs

• Patients of any age with a UTI who have a family history of renal or urologic disease, poor growth,or hypertension

• Patients who do not respond as expected to appropriate antimicrobial therapy

Indications for Voiding Cystourethrogram

• Patients of any age with two or more febrile UTIs.

• Patients of any age with a first febrile UTI who have any anomalies on renal ultrasound or a family history of renal or urologic disease; and children with poor growth or hypertension

The content on the next slide has small font, but is packed with important information for review at your leisure

Case #3A 2 y.o. boy presents to clinic for follow up after completing 14 day course of antibiotics for pyelonephritis. You ordered a VCUG and the results reveal bilateral vesicoureteral reflux (grade III on the right and grade IV of the left).

Discussion Questions:• What is the most appropriate next step in

management?

• Which condition has strong association with UTI ?

What is the most appropriate next step in management?

• Start prophylactic antibiotic therapy – Prophylactic dose if ¼ to ½ of the therapeutic dose

Suggested DosingTMP-SMZ 2 mg/kg daily or 5 mg/kg twice weeklyNitrofurantoin 1-2 mg/kg dailyCephalexin 10 mg/kg dailyAmpicillin 20 mg/kg dailyAmoxicillin 10 mg/kg daily

Vesicoureteral reflux (VUR)• Occurs when urine within the bladder flows back up into

the ureter and often back into the kidney.– Primary concern is exposing the kidneys to infected urine →

acute pyelonephritis and renal scarring

• All grades of VUR have potential for spontaneous resolution over a period of time. Percent resolution at 5 year follow up– Grade I 82% – Grade II 80%– Grade III 46%– Grades V 30%– Grade V 13%

Which condition has strong association with UTI ?

• CONSTIPATION– The association is believed to result from

compression of the bladder and bladder neck– Also distended colon or fecal soiling provides an

abundant reservoir of pathogens• Constipation in children increases the likelihood

of urinary incontinence bladder overactivity, dysfunctional voiding, recurrent UTIs and persistence or progression of VUR

Other host risk factors predisposing to Urinary Tract Infection

• Lack of circumcision of male infants (<1 year of age)• Male gender in first 6 to 8 postnatal months• Lack of breastfeeding in first 6 postnatal months• Constipation• Dysfunctional voiding pattern• Recent history of antibiotic use for any purpose• Urinary tract infection in the past 6 months• Indwelling catheters or intermittent catheterization• Family history of recurrent urinary tract infection• Recent sexual intercourse• Use of a diaphragm for birth control or spermicidal agents

Management of VUR

• Medical management is appropriate for all stages of VUR particularly in younger children– Prophylactic antibiotics, treatment of constipation and

voiding dysfunction if present• Surgical management is reserved for patients

who fail medical management or Grade IV/V– Breakthrough UTIs or persistent VUR with evidence of

renal injury• Close monitoring with periodic VCUG

examination (yearly – to every 2 years)

PREP QUESTIONS

A 4-year-old girl presents to your office for evaluation 1 month after an episode of pyelonephritis, after which she was diagnosed with grade III vesicoureteral reflux. The patient is healthy with normal growth parameters and development. She has no significant past medical history or past surgical history. According to her parents, she has been toilet trained since 18 months of age. Findings on physical examination are unremarkable; vital signs are normal. Her urine analysis in the office shows specific gravity of 1.010, pH of 6.0, and no protein, blood, leukocyte esterase, or nitrites. There is no history of urinary tract infections in the parents or the 2-year-old sister.

PREP 2014 #214

Of the following, the MOST appropriate next step in the management of this patient is to

A. evaluate the patient for voiding dysfunction B. order urine culture for evaluating resolution of

the urinary tract infection C. order serum electrolytes and serum creatinine

for evaluating renal function D. refer the patient for surgical correction of her

reflux E. screen the 2-year-old sibling with voiding

cystourethrography PREP 2014 #214

A 3-month-old female infant presents to your office for follow-up of pyelonephritis diagnosed 2 months ago. After treatment of her urinary tract infection, she had a contrast voiding cystourethrogram (VCUG) that showed narrowing of the distal urethra and a normal urinary stream upon voiding (Item Q36). Her physical examination is unremarkable. She is currently on oral amoxicillin for urinary tract infection prophylaxis.Of the following, the MOST appropriate next step in the management of this patient is

A. intravenous pyelography B. referral to urology for surgical correction C. repeat urine cultureD. repeat VCUG in 1 year E. stop prophylactic antibiotics PREP 2014 #36

Narrow urethra on VCUG (also termed spinning top urethral deformity)

References

–Pediatrics in Review Article: “Urinary tract infections and Vesicoureteral Reflux in Infants and Children” (2010)–AAP Clinical Guideline or Practice Parameter–Nelson’s reference–Harriet Lane–Uptodate

BONUS PREP QUESTIONSIf time permits

A 17-year-old, sexually active boy has complaints of intermittent burning with urination for the last 2 weeks. He says he sometimes sees some staining on his underwear but has not noticed any penile discharge or genital lesions. He reports that he has never had a sexually-transmitted infection and that he always uses condoms. He is otherwise healthy and has no systemic complaints, hematuria, or urgency. On physical examination, he is at sexual maturity rating 5 for pubertal development. Other than some moistness at the urethral meatus, his genital examination findings are normal.

PREP 2014 #20

Of the following, the organism MOST likely responsible for this boy’s symptoms is

A. Chlamydia trachomatisB. Escherichia coli C. Mycoplasma genitalium D. Neisseria gonorrhoeae E. Ureaplasma urealyticum

PREP 2014 #20

A 1-year-old with genitourinary malformations recently underwent corrective urological surgery and was discharged home in stable condition with an indwelling urinary catheter. The patient presents 10 days after discharge with fever and vomiting. Physical examination is significant only for a febrile infant (40.1°C) with mild dehydration. The urine is cloudy, and a spot urine test strip analysis shows a pH of 6.0, specific gravity of 1.040, 4+ leukocyte esterase, and no nitrites, blood, or protein. The patient is admitted to the hospital parenteral antibiotics are started.

PREP 2014 #72

Of the following, the MOST appropriate empiric antibiotic choice for this patient is intravenous

A. ampicillin B. ampicillin and ceftriaxone C. ceftriaxone D. cefuroxime and gentamicinE. gentamicin

PREP 2014 #72

THANK YOU!