Written by Vivian Lei
Appropriate diagnosis of urinary tract infection in children is important, as missed UTI can lead to renal scarring and other complications while over-diagnosis promotes antibiotic resistance.
Why does this matter?
This is a review of the current literature on UTI in children with my top 10 takeaways.
Pediatric UTI need-to-know info
Know the risk factors.
Female sex (or uncircumcised infant boy), younger age, white race, vesicoureteral reflux (VUR), congenital anomalies of the kidneys and urinary tract, bladder-bowel dysfunction, and instrumentation of the urinary tract are the important risk factors.
Symptoms aren’t always straightforward.
In verbal children, history may reveal dysuria, urgency, frequency, abdominal or flank pain, and new onset incontinence. Infants may only present with fever and nonspecific symptoms.
How urine is collected matters.
In non-toilet trained children, urine should be collected by urethral catheterization or suprapubic bladder aspiration. Other methods, such as a bag specimen or urine collected by the Quick-Wee method, are at risk for contamination and should not guide management if positive. In toilet-trained children, collect midstream urine in a sterile cup after cleaning the skin around the genital area.
Bedside UTI screening has limitations.
Urine dipstick for leukocyte esterase has relatively poor sensitivity and specificity. The addition of urine microscopy is only marginally better. Use of UA interval likelihood ratio cutoffs may also help. UTICalc was developed to help estimate the probability of UTI in febrile infants at the bedside and can guide decisions to initiate empiric antibiotics.
Get the urine culture.
Urine culture takes 1-2 days, and a positive culture depends on method of collection: ≥50,000 CFUs/mL for catheterized specimens, ≥100,000 CFUs/mL for clean catch, and ≥1000 CFUs/mL for suprapubic aspiration. The 2011 American Academy of Pediatrics (AAP) defines UTI as the presence of a clinically significant uropathogen in an appropriately obtained urine specimen with either a positive leukocyte esterase test or pyuria, although this may change as new data emerges.
It’s not always a UTI.
The most common errors encountered in diagnosis are a contaminated urine specimen, asymptomatic bacteriuria, and sterile pyuria.
Renal imaging is usually not necessary in the acute setting.
A renal bladder ultrasound (RBUS) is recommended in all infants 2-24 months with first febrile UTI, or older children with recurrent UTIs, to evaluate for urinary tract anomalies. It is usually deferred until UTI resolves unless the illness is severe.
A voiding cystourethrogram (VCUG) can be considered after first UTI in children with abnormal RBUS, atypical causative pathogen, complex clinical course, or known renal scarring.
A dimercaptosuccinic acid (DMSA) renal scintography scan is the current gold standard to assess for renal parenchymal injury after febrile UTI and may be considered in children with recurrent febrile UTIs or renal parenchymal abnormalities on RBUS.
Complications can occur in the short and long-term.
As with any febrile illness, dehydration, electrolyte abnormalities, and febrile seizures can occur, with urosepsis being the most severe complication. Upper tract infections can lead to renal scarring which may cause hypertension and chronic kidney disease.
In a child with febrile UTI, start antibiotics within 48 hours of fever onset.
Early initiation of appropriate antibiotics and prevention of recurrent UTI lowers the risk of renal scarring and complications. Most UTIs are still caused by E. coli (85-90%). Choose antibiotics based on local antibiograms and give for 7-10 days for uncomplicated febrile UTI (presumed pyelonephritis) and 3-5 days for uncomplicated nonfebrile cystitis.
Antimicrobial prophylaxis is generally not recommended.
It is selectively considered in patients with recurrent UTI and those with a high risk of renal scarring (e.g. VUR).
Contemporary Management of Urinary Tract Infection in Children. Pediatrics. 2021 Feb;147(2):e2020012138. doi: 10.1542/peds.2020-012138.