What is the appropriate workup and management for a patient presenting with scrotal pain?

Workup for Scrotal Pain

For acute scrotal pain, immediately obtain Duplex Doppler ultrasound of the scrotum to rule out testicular torsion, which requires surgical intervention within 6-8 hours to prevent testicular loss. 1, 2

Initial Clinical Assessment

Timing and Onset Characteristics

• Abrupt, severe onset suggests testicular torsion—this is a surgical emergency requiring immediate urological consultation 2
• Gradual onset is more consistent with epididymitis/epididymo-orchitis 2
• Document duration of symptoms, as testicular viability is compromised after 6-8 hours in torsion 2

Age-Specific Considerations

• Prepubertal boys: Torsion of testicular appendage is most common cause 2
• Adolescents and postpubertal boys: Testicular torsion has peak incidence (2.9-3.8 per 100,000 annually) 2
• Adults over 25 years: Epididymitis/epididymo-orchitis is overwhelmingly most common (600,000 cases annually in US) 2
• Adults over 35 years: Testicular torsion is rare 2

Physical Examination Findings

• Negative Prehn sign (pain NOT relieved with testicular elevation) indicates torsion 2
• Look for the "blue dot sign" on scrotal skin—pathognomonic for appendage torsion, though only present in 21% of cases 2
• Assess for scrotal wall thickening, hydrocele, and testicular position 1

Laboratory Testing

• Obtain urinalysis to evaluate for infection, though normal urinalysis does NOT exclude either torsion or epididymitis 2
• If urinalysis shows pyuria/bacteriuria and clinical picture suggests epididymitis, consider urine culture 2

Imaging Protocol

Duplex Doppler Ultrasound (First-Line Imaging)

Ultrasound is the diagnostic modality of choice and should include three components: 1

Grayscale Examination

• Assess testicular homogeneity (inhomogeneous pattern suggests nonviable testis) 1
• Look for "whirlpool sign" of twisted spermatic cord—96% sensitivity, 99% specificity for torsion 1, 2
• Obtain cine clip in transverse plane moving along spermatic cord to identify twisting 1

Color Doppler Assessment

• Evaluate testicular perfusion with sensitivity 96-100% and specificity 84-95% for detecting torsion 1
• Decreased or absent blood flow indicates torsion 2
• Increased flow suggests epididymitis/orchitis 1

Power Doppler

• More sensitive than color Doppler for slow flow, especially useful in prepubertal testes 1
• Use as adjunct when color Doppler is equivocal 1

When to Consider MRI

• NOT for initial evaluation of suspected torsion—time is critical 3
• Consider only if ultrasound is equivocal and clinical suspicion remains intermediate 1
• MRI shows decreased perfusion on dynamic contrast-enhanced sequences and low signal on T2-weighted images in torsion 1
• May help identify segmental testicular infarction when ultrasound is unclear 1

Differential Diagnosis and Management

Testicular Torsion (Surgical Emergency)

• Immediate urological consultation and surgical exploration is definitive treatment 2
• Surgery must occur within 6-8 hours; outcomes better when within 12 hours 2
• Ultrasound findings: absent/decreased flow, whirlpool sign, enlarged heterogeneous testis, ipsilateral hydrocele 2
• Beware false-negatives with partial torsion or spontaneous detorsion 2

Epididymitis/Epididymo-Orchitis

• Most common cause in adults; up to 20% have concomitant orchitis 1
• Ultrasound shows enlarged epididymis with increased flow, variable echogenicity, scrotal wall thickening, hydrocele 1
• Rare complication: global testicular infarction with "string-of-beads" appearance on Doppler 1
• Treat with appropriate antibiotics based on age and risk factors 2

Torsion of Testicular Appendage

• Most common in prepubertal boys 2
• Blue dot sign when present is diagnostic 2
• Ultrasound shows normal testicular flow with focal hyperemia near appendage 1
• Usually managed conservatively with analgesics 2

Segmental Testicular Infarction

• Classic wedge-shaped avascular area on ultrasound 2
• May appear round with some color flow in atypical presentations 1
• MRI helpful if ultrasound equivocal 1

Acute Idiopathic Scrotal Edema

• Rare, self-limiting, diagnosis of exclusion 1
• Usually painless with marked scrotal wall thickening showing heterogeneous striated appearance 1
• Increased scrotal wall vascularity but normal testicular and epididymal flow 1

Critical Pitfalls to Avoid

• Never delay imaging or surgical consultation based on normal urinalysis—it does not exclude torsion 2
• Significant overlap exists in clinical presentations between different causes of acute scrotal pain 2
• Partial torsion may present with less severe symptoms but still requires surgical intervention 2
• False-negative Doppler can occur with intermittent torsion or spontaneous detorsion 2
• Always use the contralateral asymptomatic testicle as internal control during ultrasound evaluation 2
• In very large scrotal masses where ultrasound is limited, MRI may be appropriate, but critically evaluate gadolinium use based on patient factors 1