Can I order an ultrasound (US) to evaluate for an inguinal hernia in a patient presenting with testicular swelling?

Can Ultrasound Diagnose Inguinal Hernia in Testicular Swelling?

Yes, ultrasound can be ordered to evaluate testicular swelling and may identify an inguinal hernia, but the primary purpose of urgent scrotal ultrasound in this presentation is to rule out testicular torsion—a surgical emergency that must be excluded first. 1

Primary Diagnostic Consideration

When a patient presents with testicular swelling, testicular torsion must be ruled out immediately, as testicular viability is compromised if not treated within 6-8 hours of symptom onset. 1 The American College of Radiology recommends that any acute scrotal pain or swelling should be treated as a potential surgical emergency until torsion is excluded. 1

Ultrasound Protocol for Testicular Swelling

Duplex Doppler ultrasound of the scrotum is the first-line imaging study, with sensitivity of 69-96.8% and specificity of 87-100% for diagnosing testicular torsion. 1 The examination should include:

• Grayscale examination to assess testicular homogeneity, identify the "whirlpool sign" of twisted spermatic cord, and evaluate for scrotal wall thickening and hydrocele 1
• Color/Power Doppler assessment of testicular perfusion compared to the contralateral side, with Power Doppler being particularly useful for detecting low-flow states in prepubertal testes 1
• Spectral Doppler analysis of the upper, mid, and lower poles of each testicle to detect regional flow variations 1

Inguinal Hernia Detection

Incarcerated inguinal hernias are an important but often overlooked cause of testicular pain and swelling. 2, 3 While ultrasound can identify herniated contents extending into the scrotum during the grayscale examination, this is a secondary finding. 1 An incarcerated inguinal hernia represents an emergent condition requiring prompt surgical intervention. 2, 3

Key Ultrasound Findings for Hernia

During the scrotal ultrasound, the sonographer can visualize:

• Bowel loops or other abdominal contents extending through the inguinal canal into the scrotum 3
• Scrotal wall thickening and hydrocele, which may be present with either torsion or incarcerated hernia 1

Critical Clinical Pitfalls

A normal ultrasound does not exclude testicular torsion. False-negative Doppler evaluations occur in 30% or more of cases, particularly with partial torsion, spontaneous detorsion, or early presentation. 1 When clinical suspicion for torsion remains high despite normal Doppler findings, immediate urological consultation and surgical exploration should proceed. 1

Do not delay imaging or surgical consultation if there is high clinical suspicion for either testicular torsion or incarcerated hernia, as both are time-sensitive surgical emergencies. 1, 2

Age-Specific Differential Diagnosis

The differential diagnosis for testicular swelling varies by age:

• Prepubertal boys: Torsion of testicular appendage is most common, followed by testicular torsion 1
• Adolescents (12-18 years): Testicular torsion is most common, with peak incidence in this age group 1, 4
• Adults over 25 years: Epididymitis/epididymo-orchitis is most common (approximately 600,000 cases annually in the US), though testicular torsion can still occur 1
• Adults of any age: Incarcerated inguinal hernia should be considered, especially with visible groin or scrotal swelling 2, 3

Management Algorithm

1. Order urgent Duplex Doppler ultrasound for any patient presenting with testicular swelling 1
2. Obtain immediate urological consultation if ultrasound shows decreased/absent testicular blood flow, whirlpool sign, or if clinical suspicion for torsion remains high despite normal imaging 1
3. Identify incarcerated hernia if bowel or other abdominal contents are visualized in the scrotum, and obtain emergent surgical consultation 2, 3
4. Do not let imaging delay surgical exploration when clinical suspicion is high for either torsion or incarcerated hernia 1, 4