MP80-02 INCREASED URINARY CALCIUM EXCRETION IS MORE COMMON IN YOUNGER STONE FORMERS.

Abstract

INTRODUCTION AND OBJECTIVES: Ureteral colic due to an obstructing stone is a common presentation to the emergency department. We sought to evaluate how often serum and urine studies were unremarkable in patienst with this presentation. METHODS: Two hundred thirty-two consecutive patients evaluated in an urban tertiary care emergency department and who were diagnosed with an obstructing ureteral stone on computerized tomography (CT) were evaluated. Inclusion criteria were as follows: ureteral stone diagnosed on CT, urine dipstick and serum WBC checked. Studies were considered “normal” if urine dipstick showed 0 RBC, 0 WBC, and was nitrite negative AND if serum WBC was < 12.0. RESULTS: Mean patient age was 46.9 years (SD 15.4), gender prevalence was 35.8% female:64.2% male, mean axial stone diameter was 4.0 mm (SD 2.0), and mean serum WBC was 10.1 (SD 3.7). Stone position was proximal ureter e 24.6%, distal ureter e 27.1%, and ureterovesical junction e 48.3%. Completely normal urine dipstick and serum WBC was seen in 47 patients (20.2%), whereas 185 patients (79.7%) demonstrated at least a single abnormality of urine dipstick or WBC. On mulvariate logistic regression, neither age, gender, stone location, or stone size were significant predictors of the presence or absence of laboratory abnormalities. CONCLUSIONS: Up to 20% of patients presenting with ureteral colic and ureteral stones will not demonstrate abnormalities of urine dipstick or serum WBC. These data may be helpful in selecting which patients may benefit from additional imaging or workup in cases when the diagnosis is not obvious.