Category: Clinical Stones: Outcomes

MP22-16 - The use of biomarkers to diagnose infected ureteral stones in clinically equivocal patients

Sat, Sep 22
2:00 PM - 4:00 PM

Introduction & Objective :

Infected ureteral stones are a urologic emergency and require urgent genitourinary decompression. However, urine culture (UCx) results take >24 hours to result and many patients with acute ureterolithiasis present to the Emergency Room with clinically equivocal signs of infection. We seek to identify if there are any biomarkers that may provide superior diagnosis of infected ureteral stones at the time of presentation.

Methods :

In this IRB-approved prospective observational study, all consecutive patients presenting to the emergency room with nephrolithiasis and a Urology consultation were recruited. All patients had complete blood count (CBC) with differential, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), urinalysis (UA), procalcitonin (PCT) and urine culture with or without intraoperative cultures. Patients with positive and negative UCx were compared. Subgroup analysis was performed in a “clinically difficult” cohort of afebrile patients who had a leukocytosis >10x109 cells/L and UA with <50 WBCs per HPF (high powered field).

Results :

149 patients have been recruited to the study (Table 1). Of this cohort, 20% had a positive urine cultured and 15% were defined as clinically difficult. In the entire and clinically difficult cohort, there were statistical differences in PCT, UA WBCs, CRP, WBC count and neutrophil % as shown in Table 1. ROC analysis, sensitivity and specificity for the clinically difficult patients are shown in Table 2. In the clinically difficult cohort, CRP had the highest area under the curve (AUC) at 0.791. When combining UA WBC and neutrophil % in series, a 95.1% sensitivity is obtained. Combining neutrophil % with PCT in serial fashion provides a sensitivity of 95.1%.

Conclusions :

In clinically difficult patients, UA, WBC and neutrophil % can be combined in parallel or PCT and neutrophil % can be serially combined to provide excellent sensitivity. The use of biomarkers amongst patients with obstructing ureterolithiasis may help clinicians diagnose those who are subclinically infected at the time of presentation.

Patrick Whelan

Resident Physician
Rush University Medical Center
Chicago, Illinois

Edward Capoccia

Rush University Medical Center
Chicago, Illinois

Edward Capoccia, MD, Rush Urology Medical Center. I am currently a PGY4 with an interest in endourology fellowship.

Dimitri Papagiannopoulos

Fellow Physician
University of California San Diego
San Diego, California