The role of a urine dipstick in the diagnosis of the acute scrotum

Abstract Objective To evaluate the role of a urine dipstick in the assessment of acute scrotal pain emergency department presentations. Methods A single institution, prospective case series, from February 2020 to February 2021. All patients who received a bedside review by a urology doctor for acute scrotal pain were included. Urine dipstick results were pre‐defined as having had an impact on the emergency clinician's diagnosis if it showed pyuria and/or nitrituria and the final diagnosis was epididymitis‐orchitis or haematuria and the final diagnosis was ureterolithiasis. Results 139 patients presented to the emergency department with a complaint of acute scrotal pain. 85 (61%) were referred for bedside urology review. Median age of 17 years (P25 12 yrs, P75 31 yrs). 2.3% (n = 2) had proven testicular torsion, 28.5% (n = 24) had epididymitis‐orchitis and 8.2% (n = 7) had ureterolithiasis. 68 (80%) of patients received a primary diagnosis of testicular torsion by the emergency department clinician. Following review by a urology unit doctor, 14 proceeded to scrotal exploration for concern of testicular torsion. 7 patients were diagnosed with ureterolithiasis, all of whom had haematuria on their urine dipsticks (100%, 95% CI: 59–100%), 100% of these urine dipsticks were initiated by the urology unit doctor following bedside review. 22 patients were diagnosed with epididymitis‐orchitis. 8 of these had pyuria, nitrituria and/or haematuria on their urine dipstick (36%, 95% CI: 17–59%) and only one urine dipstick was completed prior to referral. 20.6% of patients perceived to have testicular torsion by the emergency department had a positive urine dipstick that aligned with their final alternative diagnosis (95% CI: 12–32%). Conclusion A collection of clinical findings is required to diagnose the aetiology of acute scrotal pain. Information that can be easily, quickly, cheaply, and reliably collected, such as a urine dipstick, can assist in clinical decision making.


| INTRODUCTION
Scrotal pain is a common emergency department presentation, with a spectrum of probable diagnoses ranging from a benign pathology requiring no treatment, to acute testicular torsion requiring urgent operative intervention. 1 Haday and Reynard highlighted in their metaanalysis the need for exploration of the testis within 6 h of pain, with a testicular viability of 98% within this time. 2 The concern for missing the diagnosis of a testicular torsion and subsequently delaying intervention resulting in orchidectomy for an ischaemic testicle necessitates the hasty referral of patients for specialty review.
In addition to time pressures, acute scrotal pain is a complex clinical presentation for junior doctors to navigate. Menzies-Wilson et al recently demonstrated, using the English National Health Service Trust data, that the individual doctors' experience was the greatest risk to misses of testicular torsion in 88% of cases. 3 Due to the variability in clinical presentations, and the lack of an accurate, simple and timely diagnostic tool to rule out testicular torsion, patients are frequently referred to a urology unit doctor for specialist bedside assessment.
Differential diagnosis of torsion of the testicular appendage, epididymo-orchitis or ureterolithiasis is also found in patients who present with acute scrotal pain. The presence of haematuria, pyuria and/or nitrituria in the setting of infection and the presence of haematuria in the setting of ureterolithiasis may assist in guiding towards these alternative diagnoses.
We aimed to quantify the role of urine dipsticks in the diagnosis of the aetiology of acute scrotal pain emergency department presentations and the impact it could have on the initial emergency department referral diagnosis if it were to be completed prior to contacting a urology unit doctor.

| METHODS
A prospective case series of males presenting with acute scrotal pain to a single institution over a 12-month period from the 3rd of February 2020 to the 31st of January 2021 was undertaken. Only patients who were referred to and reviewed at the bedside by a doctor working in the urology department were included. Ethic's approval was gained from the Barwon Health Ethics Department, Reference Number #20/181. Data were collected prospectively by the treating urology unit doctor and stored in a secure database.

| RESULTS
One hundred thirty-nine patients presented within the research period to the emergency department with a complaint of acute scrotal pain according to the preselected VEDD ICD-10 codes. Eighty-five (61%) of these emergency department presentations were referred for bedside urology review in 79 different patients, and this was our study cohort.
The median age of patients presenting with acute scrotal pain was 17 years (IQR: 12-31 years). 2.3% (n = 2) had testicular torsion, 28.2% (n = 24) had epididymo-orchitis, and 8.2% (n = 7) had ureterolithiasis (Table 1) Fourteen were reviewed by the urology unit doctor and proceeded to scrotal exploration for concern for testicular torsion. Two of these patients had testicular torsion, three had normal testicles, four epididymo-orchitis, and five had torsion of the testicular appendage.  Limitations of our study include the small sample size, in particular the low number of patients with testicular torsion in our cohort. As a single-institution study, it represents only one emergency and one urology department's management of patients with acute scrotal pain.
Despite these limitations, our data currently justify the routine use of urine dipstick in the workup of acute scrotal pain. Clinical integration into diagnostic algorithms such as the TWIST score 7 for the workup of testicular ischemia may occur into the future, with a positive urine dipstick result equating to a negative score towards a testicular torsion diagnosis. Acknowledging that its integration would need to occur with the overarching principle that clinical judgement in each clinical scenario remains paramount.

| CONCLUSION
A urine dipstick is a contributing adjunct in the workup of patients who present to the emergency department with acute scrotal pain.
The result of the urine dipstick should be used in conjunction with other clinical findings and if concern remains that the patient has testicular torsion irrespective of the dipstick result the clinician should proceed to scrotal exploration.