Increasing incidence of asymptomatic and symptomatic urolithiasis in children undergoing abdominal imaging at a Canadian tertiary care centre
Raees Cassim, BHSc1, Luke Lavallée, MDCM MSc2, Carl Van Walraven, MD MSc2, Kristen McAlpine, MD1, Carolyn Wayne, MSc1, Luis Guerra, MD MS1, Michael Leonard, MD1, Melise Keays, MD MSc1.
1Children's Hospital of Eastern Ontario, Ottawa, ON, Canada, 2The Ottawa Hospital, Ottawa, ON, Canada.
BACKGROUND: There are few studies evaluating the incidence of urolithiasis in pediatric patients undergoing abdominal imaging. Our objective was to estimate the incidence of urolithiasis in pediatric patients undergoing abdominal ultrasound (US) or computerized tomography (CT) at our children’s hospital using textual analysis of imaging reports.
METHODS: REB approved retrieval of radiology reports for all patients under 18 years of age having abdominal US or CT between January 1, 2011 and December 31, 2015. Using SAS, reports were flagged if they contained keywords (Table 1) potentially indicating urolithiasis. All flagged reports as well as 10% of unflagged reports were manually reviewed to confirm the presence or absence of stones. Patient and stone related clinical data were extracted.
RESULTS: 1987 of 44 225 (5%) imaging reports cited at least one of the keywords. Manual review identified 382 studies as confirmed stones (182 unique patients). 89 studies with possible stones were omitted (11 had twinkle artifact and 27 had posterior shadowing alone). 106 (58.2%) patients were symptomatic and 76 (41.8 %) patients were asymptomatic. The incidence of stones in patients undergoing abdominal evaluation increased from 316 (95% CI 200-480) to 580 (95% CI 420-790) per 100 000 patients between 2011 and 2015 (Figure 1). The incidence of both symptomatic and asymptomatic stones rose during this time period. Overall, 45.1% (82/182) of stones resolved spontaneously, 14.8% (27/182) required surgical management to relieve symptoms or obstruction, 5.5% (10/182) required medical expulsive therapy, and 34.7% (63/182) were unresolved at last follow-up. Of note, only 2.6% (2/76) of asymptomatic stones underwent therapy. Furthermore, 56.6% (43/76) of asymptomatic stones resolved spontaneously in a mean of 10.5 (SD 9.5) months. Asymptomatic and symptomatic stones were followed for similar lengths of time (2.65 vs 2.18 years, p >0.05) and had a similar number of follow-up ultrasounds (4.18 vs 4.93 studies, p >0.05).
CONCLUSIONS: The incidence of radiologically identified stones in children undergoing abdominal imaging at our pediatric center increased over time. While most asymptomatic stones resolved spontaneously, they were found to have similar follow up and imaging utilization as symptomatic stones.
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