In a teenage male with 10 hours of acute scrotal pain that is relieved by elevation of the testes (positive Prehn sign), what is the next best step in management?

Management of Acute Scrotal Pain with Positive Prehn Sign in a Teenage Male

Immediate Action Required

Despite the positive Prehn sign suggesting epididymitis, you must proceed with urgent Doppler ultrasound and maintain high suspicion for testicular torsion, as clinical signs overlap significantly and testicular salvage depends on intervention within 6-8 hours. 1

Why Clinical Signs Are Unreliable

The traditional teaching that pain relief with testicular elevation (positive Prehn sign) rules out torsion is dangerously misleading in practice:

• Testicular torsion is characterized by a negative Prehn sign (pain NOT relieved by elevation), making it a key distinguishing feature 1, but the converse—that pain relief confirms epididymitis—is not reliable enough to exclude torsion 1

• The American College of Radiology emphasizes that significant overlap exists in clinical presentation between different causes of acute scrotal pain, making diagnosis challenging 1

• In adolescents, the three most common causes (testicular torsion, torsion of testicular appendage, and epididymitis) can present with remarkably similar symptoms 1

• False-negative Doppler evaluations occur in 30% or more of cases, particularly with partial torsion or early presentation 1, meaning even imaging can miss the diagnosis

The Correct Diagnostic Algorithm

Step 1: Immediate Urological Consultation

Any acute scrotal pain must be treated as a potential surgical emergency until torsion is excluded 1. Do not delay consultation based on physical exam findings alone.

Step 2: Urgent Doppler Ultrasound (Within 1-2 Hours)

Duplex Doppler ultrasound is the first-line imaging study with sensitivity of 69-96.8% and specificity of 87-100% 1. The examination must include:

• Grayscale assessment for the "whirlpool sign" of twisted spermatic cord (96% sensitivity) 2, 1
• Color Doppler to compare testicular perfusion between sides 2, 1
• Power Doppler for detecting low-flow states, particularly useful in adolescents 2, 1
• Spectral Doppler analysis of upper, mid, and lower poles to detect regional flow variations 1

Step 3: Interpretation of Ultrasound Findings

For Testicular Torsion:

• Decreased or absent blood flow to the affected testicle 1
• Whirlpool sign of twisted spermatic cord 1
• Enlarged heterogeneous testis appearing hypoechoic 1
• Ipsilateral hydrocele and scrotal skin thickening 1

For Epididymitis:

• Enlarged epididymis with increased blood flow on color Doppler 2, 1
• Scrotal wall thickening and hydrocele 2, 1
• Up to 20% concomitant orchitis rate 2

Step 4: Decision Point

If ultrasound shows decreased/absent flow OR if imaging cannot be completed within 1-2 hours: Proceed immediately to surgical exploration 3. When clinical suspicion for torsion remains high despite normal Doppler, immediate surgical exploration should proceed 1.

If ultrasound clearly demonstrates epididymitis with normal testicular perfusion: Treat medically but arrange close follow-up within 24-48 hours 1.

Critical Pitfalls to Avoid

The "Positive Prehn Sign" Trap

Your patient's pain relief with elevation does NOT exclude torsion. Partial torsion may present with less severe symptoms but still requires surgical intervention 1. Partial or incomplete torsion presents the greatest diagnostic challenge because arterial flow may persist as venous obstruction occurs first 1.

The Time Window Error

Surgical exploration and detorsion must be performed within 6-8 hours of symptom onset to prevent permanent ischemic damage 1. Your patient is already at 10 hours—you are in the critical window where any delay increases the risk of testicular loss 1.

The "Normal Ultrasound" Mistake

Even with normal Doppler findings, if clinical suspicion remains high, immediate urological consultation and surgical exploration should proceed 1. False-negative evaluations occur with partial torsion, spontaneous detorsion, or early presentation within the first few hours 1.

Age-Specific Considerations

In your teenage patient:

• Testicular torsion occurs more frequently in adolescents with a bimodal distribution peaking in neonates and postpubertal boys 1
• Epididymitis remains a common cause in adolescents and young adults 1, but in sexually active teens, consider Chlamydia trachomatis and Neisseria gonorrhoeae 4, 5
• The risk of developing torsion by age 25 is approximately 1 in 160 6

Rare but Important Consideration

Epididymo-orchitis can actually precipitate testicular torsion 7. The enlarged, inflamed testis creates a predisposing anatomical condition for subsequent torsion, meaning even if your initial diagnosis is epididymitis, close follow-up and adequate counseling on warning signs is of particular importance 7.