A Comparison of Urolithiasis in the Presence and Absence of Microscopic Hematuria in the Emergency Department

Abstract

IntroductionUrolithiasis is a common medical condition that accounts for a large number of emergency department (ED) visits each year and contributes significantly to annual healthcare costs. Urinalysis is an important screening test for patients presenting with symptoms suspicious for urolithiasis. At present there is a paucity of medical literature examining the characteristics of ureteral stones in patients who have microscopic hematuria on urinalysis versus those who do not. The purpose of this study was to examine mean ureteral stone size and its relationship to the incidence of clinically significant hydronephrosis in patients with and without microscopic hematuria.MethodsThis is a retrospective chart review of patient visits to a single, tertiary academic medical center ED between July 1, 2008, and August 1, 2013, of patients who underwent non-contrast computed tomography of the abdomen and pelvis and urinalysis. For patient visits meeting inclusion criteria, we compared mean stone size and the rate of moderate-to-severe hydronephrosis found on imaging in patients with and without microscopic hematuria on urinalysis.ResultsOut of a total of 2,370 patient visits 393 (16.6%) met inclusion criteria. Of those, 321 (82%) had microscopic hematuria present on urinalysis. Patient visits without microscopic hematuria had a higher rate of moderate-to-severe hydronephrosis (42%), when compared to patients with microscopic hematuria present (25%, p=.005). Mean ureteral stone size among patient visits without microscopic hematuria was 5.7 mm; it was 4.7 mm for those patients with microscopic hematuria (p=.09). For ureteral stones 5 mm or larger, the incidence of moderate-to-severe hydronephrosis was 49%, whereas for ureteral calculi less than 5 mm in size, the incidence of moderate-to-severe hydronephrosis was 14% (p < 0.0001).ConclusionPatients visiting the ED with single-stone ureterolithiasis without microscopic hematuria on urinalysis could be at increased risk of having moderate-to-severe hydronephrosis compared to similar patients presenting with microscopic hematuria on urinalysis. Although the presence of hematuria on urinalysis is a moderately sensitive screening test for urolithiasis, these results suggest patients without hematuria tend to have more clinically significant ureteral calculi, making their detection more important. Clinicians should maintain a high index of suspicion for urolithiasis, even in the absence of hematuria, since ureteral stones in these patients were found to be associated with a higher incidence of obstructive uropathy.

Prevalence of microhematuria in renal colic and urolithiasis: a systematic review and meta-analysis

“…Patients presenting with acute renal colic at the emergency department Authors Year Country Study design No. of patients % Male Mean age ± SD (years) Kim et al [ 13 ] 2018 South Korea Retrospective, observational 798 68.6 48.2 ± 13.3 Desai et al [ 14 ] 2018 USA Retrospective, observational 350 NR NR Türk and Ün [ 15 ] a 2017 Turkey Prospective, observational 516 60.5 37 ± 20.3 Shrestha et al [ 16 ] a 2017 Nepal Retrospective, observational 201 55.2 29 ± 13.5 Odoemene et al [ 17 ] a 2017 Nigeria Prospective, observational 69 76.8 40.4 ± 2.9 Mefford et al [ 18 ] 2017 USA Retrospective, observational 393 69 Median 43 (IQR 32–54) Rapp et al [ 19 ] 2016 USA Retrospective, observational 613 47 49 ± 0.6 Park et al [ 20 ] 2016 South Korea Prospective, RCT 103 66 45.6 ± 12.55 Hernandez et al [ 21 ] 2016 USA Retrospective, observational 536 56 45.9 ± 16.3 <...>…”

“…Kim et al [ 13 ] found negative microhematuria in patients with lower stones or elevated serum blood urea nitrogen (BUN). Mefford et al [ 18 ] showed an increased prevalence of hydronephrosis in patients with urolithiasis and negative microhematuria. As hydronephrosis is easy to screen with ultrasonography, Daniel et al [ 60 ] developed the STONE PLUS Score with addition of point-of-care ultrasound of the kidney to the original STONE Score.…”

Prevalence of microhematuria in renal colic and urolithiasis: a systematic review and meta-analysis

“…Mefford et al [18] showed an increased prevalence of hydronephrosis in patients with urolithiasis and negative microhematuria. As hydronephrosis is easy to screen with ultrasonography, Daniel et al [60] developed the STONE PLUS Score with addition of point-of-care ultrasound of the kidney to the original STONE Score.…”

Characteristics and evolution of patients with urinary lithiasis in a tertiary hospital emergency

“…Similar a otros reportes donde indican como complicaciones más frecuentes infección, hematuria y obstrucción de la vía urinaria (hidronefrosis). Cabe recalcar que es importante tener presente posibles diagnósticos diferenciales según cada caso (3)(4)(5)8) y la mayoría de casos en hidronefrosis no se produce hematuria por lo que el examen de orina sería normal (13) .…”