Assessing the Utility of Ultrasound and Urinalysis for Patients with Possible Epididymo-Orchitis – A Retrospective Study

PURPOSE: Many experts recommend ordering an ultrasound and a urinalysis on all patients with scrotal pain. While the ultrasound may help diagnose a number of potential causes of scrotal pain, the urinalysis primarily has value in assessing for epididymo-orchitis. This study sought to evaluate the utility of these diagnostic tests for patients who presented to the emergency department (ED) with acute scrotal pain and possible epididymo-orchitis. PATIENTS AND METHODS: This was a single-center chart review of patients presenting to the ED with scrotal pain. Trained research assistants reviewed charts to obtain urinalysis and ultrasound results as well as diagnoses and treatments provided. Using the final diagnosis as a gold standard, the sensitivity and specificity of ultrasound and urinalysis were calculated for the diagnosis of epididymo-orchitis. Also, through a prespecified definition of “changed management,” we estimated the percentage of cases in which a urinalysis changed management of patients with acute scrotal pain. RESULTS: We identified 663 adult and pediatric patients who presented with scrotal pain during 2016. All patients had an ultrasound performed, and 458 (69.1%) had a urinalysis done. The sensitivity of urinalysis for epididymo-orchitis was 58.2% (95% CI 48.9% to 67.1%), and the specificity was 85.1% (95% CI 80.8% to 88.7%). For ultrasound, the sensitivity was 78.8% (95% CI 71.4% to 85.0%) and the specificity was 98.1% (95% CI 96.4% to 99.1%). In 24 of 458 cases (5.2% [95% CI 3.4% to 7.7%]) where a urinalysis was obtained, its results may have changed management of the patient. CONCLUSION: The diagnosis of patients who present to the ED with scrotal pain is primarily driven by the ultrasound results. While the urinalysis may occasionally provide some benefit in the evaluation of patients with suspected epididymo-orchitis, the reflexive ordering of a urinalysis in patients with scrotal pain may be unnecessary.