What are the possible diagnoses for a 4-year-old (four years old) male patient presenting with right testicular swelling?

Differential Diagnosis for Right Testicular Swelling in a 4-Year-Old

In a 4-year-old boy with testicular swelling, the three most likely diagnoses are torsion of testicular appendage (most common in this age group), testicular torsion (surgical emergency), and epididymitis/epididymo-orchitis, with immediate evaluation required to rule out testicular torsion within 6-8 hours to prevent testicular loss. 1

Age-Specific Diagnostic Considerations

At 4 years of age, this patient falls into the prepubertal category where specific pathologies predominate:

• Torsion of testicular appendage is the most common cause of acute testicular pain and swelling in prepubertal boys 1, 2
• Testicular torsion has a bimodal distribution with peaks in neonates and postpubertal boys, but can occur at any age including prepubertal children 1, 3
• Epididymitis/epididymo-orchitis is less common in prepubertal boys compared to adolescents and adults, but remains in the differential 1, 2

Critical Time-Sensitive Diagnosis: Testicular Torsion

Despite being less common in this age group, testicular torsion must be ruled out emergently:

• Testicular torsion requires surgical intervention within 6-8 hours of symptom onset to prevent permanent testicular loss 1, 3, 2
• Prepubertal males are at higher risk for orchiectomy (42.4%) compared to postpubertal males (24.1%) when torsion occurs 4
• Prepubertal boys are more likely to present with atypical symptoms including abdominal pain (27.3% of cases), which can delay diagnosis 4

Key Clinical Features of Testicular Torsion:

• Abrupt onset of severe scrotal pain developing within minutes 3
• Pain NOT relieved when testicle is elevated (negative Prehn sign) 1, 3
• Nausea and vomiting often present 3
• Absent cremasteric reflex 5
• Scrotal swelling and redness 3

Most Likely Diagnosis: Torsion of Testicular Appendage

In prepubertal boys, this is statistically the most common cause:

• Presents with localized testicular pain and swelling 1, 2
• May show the pathognomonic "blue dot sign" (visible through skin in only 21% of cases) 1, 2
• Normal testicular perfusion on Doppler ultrasound with localized hyperemia near the appendage 1
• Generally self-limiting and managed conservatively 2

Additional Differential Diagnoses

Epididymitis/Epididymo-orchitis:

• More gradual onset of pain compared to torsion 1, 2
• Positive Prehn sign (pain relief with testicular elevation) 2
• Enlarged epididymis with increased blood flow on Doppler ultrasound 1
• May have abnormal urinalysis, though normal urinalysis does not exclude it 1

Other Considerations:

• Acute idiopathic scrotal edema: Rare, self-limiting, usually painless with marked scrotal wall thickening 1
• Hydrocele: Can present with scrotal swelling 6
• Trauma: History is key, though trauma can be a "red herring" as progressive pain suggests torsion 2
• Henoch-Schönlein purpura: Consider if systemic symptoms present 6

Diagnostic Algorithm

Immediate Clinical Assessment:

• Onset and duration of symptoms (sudden vs. gradual) 1
• Presence of nausea/vomiting 3
• Abdominal pain (critical in prepubertal boys) 4
• Prehn sign testing 1, 2
• Cremasteric reflex assessment 5
• Look for "blue dot sign" 1, 2

Imaging Protocol:

• Duplex Doppler ultrasound is first-line imaging with sensitivity 69-96.8% and specificity 87-100% 1
• Grayscale examination should assess for "whirlpool sign" of twisted spermatic cord 1
• Color/Power Doppler assessment of testicular perfusion (Power Doppler particularly useful in prepubertal testes with normally slow flow) 1
• Compare to contralateral testis as internal control 1

Critical Pitfall:

• False-negative Doppler evaluations occur in up to 30% of cases, particularly with partial torsion 1, 3
• Prepubertal boys normally have reduced intratesticular blood flow, which can lead to false-positive interpretations 1

Management Based on Clinical Suspicion

High Clinical Suspicion for Torsion:

• Immediate urological consultation and surgical exploration without waiting for imaging if clinical suspicion is high 1, 2
• Do NOT delay for imaging when presentation strongly suggests torsion 2

Intermediate Suspicion:

• Urgent Doppler ultrasound 1
• Urological consultation based on imaging results 1

Low Suspicion with Imaging Confirming Alternative Diagnosis:

• Torsion of appendage: Conservative management with rest, elevation, analgesia 1
• Epididymitis: Bed rest, scrotal elevation, analgesics, appropriate antibiotics if indicated 1

Key Clinical Pearls

• Any acute scrotal pain/swelling must be treated as potential surgical emergency until torsion is excluded 2
• Perform genital examination in ALL prepubertal males presenting with abdominal pain 4
• The risk of orchiectomy decreases by 14% per 1-year increase in age, making younger children particularly vulnerable 4
• Clinical presentations of the three most common causes significantly overlap, making diagnosis challenging 2
• When in doubt, surgical exploration is safer than observation given the 6-8 hour window for testicular salvage 1, 3, 2