The utility of the urinalysis as a potential marker to diagnose urinary tract infection (UTI) in patients with neurogenic bladder is controversial. We assessed the baseline urine characteristics and intraindividual variance of pyuria in a cohort of asymptomatic children with neurogenic bladder followed longitudinally.

A cohort of 54 children with neurogenic bladder was followed from 2004 to 2015 at a single institution’s multidisciplinary clinic. Urine data obtained from 529 routine urology visits were reviewed. Urine obtained within 2 weeks before or after treatment for UTI were excluded. Bladder surgery was defined as any operation that altered the bladder as a closed or sterile system. The effects of age, gender, catheterization, and bladder surgery on pyuria were evaluated using mixed-model regression analysis.

Fifty patients with 305 urine samples had a mean length of follow-up of 3.2 years. Only 16/50 patients (32%) never had pyuria, and these patients had shorter follow-up compared with the group who ever had pyuria (≥5 white blood cells per high powered field) (1.7 vs. 3.8 years; P = 0.008). Catheterization was associated with a 15% increase in pyuria (P = 0.21). Surgery was associated with a 120% increase in pyuria (P < 0.001). The test-to-test variance of pyuria within an individual was consistently greater than between individuals (P < 0.001).

Bladder surgery is associated with significant increases in pyuria among children with neurogenic bladder. The substantial test-to-test variation in pyuria in asymptomatic individuals indicates the low reliability of pyuria, when positive, as a marker for UTI in neurogenic bladder and the need to search for either methods to reduce this variability or alternative biomarkers of UTI in this population.

The Pediatric infectious disease journal. 2019 Jun 20 [Epub ahead of print]

Ruthie R Su, Mari Palta, Amy Lim, Ellen R Wald

From the Department of Urology., Department of Population Health Sciences., Department of Pediatrics, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin.