Who needs an ultrasound? Using patient symptom questionnaire & UTI history to determine when to obtain an RBUS in children with non-neurogenic lower urinary tract dysfunction

Abstract

Introduction: Non-neurogenic lower urinary tract dysfunction (LUTD) is one of the most common reasons for presentation to a pediatric urologist, affecting up to 20% of children. Predicting who will benefit from RBUS as part of their work-up is challenging as the majority will have normal imaging.

Objective: Our objective was to assess the utility of using the Dysfunctional Voiding and Incontinence Scoring System (DVISS) and urinary tract infection (UTI) history to predict which LUTD patients were most likely to have an abnormal RBUS as well as determine a DVISS cutoff to aid in making this prediction. We hypothesized that higher DVISS scores and a positive urinary tract infection (UTI) history would be associated with increased likelihood of RBUS abnormality.

Study design: We retrospectively reviewed outpatients seen for LUTD from 5/2014-1/2016 who received an RBUS. Association between prior UTI, DVISS score, gender, and race and RBUS abnormality were evaluated using logistic regression analysis. Receiver operating characteristic (ROC) curves were created to evaluate the predictive model and a Youden index calculated to determine the optimal cutoff for DVISS score to predict abnormal RBUS.

Results: 15 of 333 patients (4.5%) had a clinically significant RBUS abnormality. Significantly more patients with abnormal RBUS had a positive UTI history and median DVISS was higher. UTI history and DVISS score were associated with RBUS abnormality whereas neither gender nor race were. A DVISS score cutoff of 12 was determined to be ideal for predicting abnormal imaging. Using DVISS≥12 and positive UTI history, patients with both risk factors were significantly more likely to have an abnormal RBUS than those with zero or one risk factor (Figure).

Discussion: To the best of our knowledge this is the first study to try to identify risk factors associated with RBUS abnormality in pediatric LUTD patients and create an evidence-based approach to imaging these patients. We found both DVISS cutoff ≥12 and positive UTI history to be useful to risk stratify LUTD patients' likelihood of abnormal RBUS. Limitations include the study's retrospective nature as well as the fact the population was drawn from a tertiary care pediatric hospital with a large referral population and the fact that the decision to order an RBUS was based on individual clinician preference and decision making.

Conclusions: We found that DVISS score≥12 and UTI history are useful in guiding the decision to obtain RBUS in pediatric LUTD patients.

Keywords: DVISS score; Non-neurogenic lower urinary tract dysfunction; Renal bladder ultrasound; Urinary tract infection; Voiding dysfunction.