What is the diagnosis and treatment for a patient with a larger left testicle compared to the right, tenderness to touch, and no history of trauma?

Diagnosis and Management of Unilateral Testicular Enlargement with Tenderness

This patient requires immediate scrotal ultrasound with Doppler to rule out testicular torsion, which is a surgical emergency that can result in testicular loss if not treated within 6-8 hours. 1

Immediate Diagnostic Approach

Order urgent Duplex Doppler ultrasound of the scrotum immediately – this is the established first-line imaging modality with 96-100% sensitivity for detecting testicular torsion and 98-100% accuracy for distinguishing intratesticular from extratesticular processes. 1

The ultrasound must include:

• Grayscale examination to assess testicular size, homogeneity, and identify the "whirlpool sign" of twisted spermatic cord (96% sensitivity) 2, 3
• Color Doppler assessment comparing blood flow between both testicles (96-100% sensitivity for torsion) 2, 3
• Power Doppler for enhanced detection of low-flow states 1, 2
• Spectral Doppler analysis of upper, mid, and lower poles of each testicle 2

Critical Differential Diagnoses

Testicular Torsion (Surgical Emergency)

Key features:

• Abrupt onset of severe scrotal pain 2
• Decreased or absent blood flow on Doppler ultrasound 1, 2
• "Whirlpool sign" of twisted spermatic cord on grayscale 1, 2
• Enlarged heterogeneous testis appearing hypoechoic 1, 2
• High-riding, horizontally oriented testicle 4
• Absent cremasteric reflex 4

Management: Immediate urological consultation and surgical exploration within 6-8 hours of symptom onset to prevent permanent ischemic damage. 1, 2 Testicular viability is compromised after this window, with salvage rates dropping significantly after 12 hours. 2, 3

Epididymitis/Epididymo-orchitis (Most Common in Adults)

Key features:

• Gradual onset of pain (unlike torsion's abrupt onset) 2
• Enlarged epididymis with increased blood flow on color Doppler 1, 2
• Scrotal wall thickening and hydrocele 2
• May have abnormal urinalysis (though normal urinalysis doesn't exclude it) 2

Management: Bed rest, scrotal elevation, analgesics, and appropriate antibiotic therapy. 2

Other Considerations

• Testicular tumor: US is nearly 100% sensitive for detecting intrascrotal masses, though cannot definitively differentiate benign from malignant lesions 1
• Hematoma: Can occur without trauma and appears avascular on Doppler 1
• Segmental testicular infarction: Wedge-shaped avascular area on ultrasound 2

Critical Clinical Pitfalls

Do not delay surgical consultation if clinical suspicion for torsion is high, even with reassuring ultrasound findings. 2, 3 False-negative Doppler evaluations occur in up to 30% of cases, particularly with:

• Partial torsion (where arterial flow may persist because venous obstruction occurs first) 2
• Spontaneous detorsion 1
• Early presentation within first few hours 2

Color Doppler sensitivity ranges from 69-96.8%, meaning it is not perfect and clinical judgment must prevail when suspicion is high. 2

Management Algorithm

1. High clinical suspicion for torsion (severe pain, abrupt onset, tender enlarged testicle): Proceed directly to immediate urological consultation and surgical exploration – do not wait for imaging if it will cause delay. 2, 3

2. Intermediate suspicion: Obtain urgent Duplex Doppler ultrasound immediately. 2

   • If decreased/absent flow → immediate surgical exploration 1, 2
   • If increased flow with enlarged epididymis → treat as epididymitis 2
   • If normal flow but high clinical suspicion persists → proceed to surgical exploration anyway 2, 3

3. Any acute scrotal pain must be treated as a potential surgical emergency until torsion is excluded. 2

The absence of trauma history does not exclude serious pathology – hematomas can occur without trauma, and testicular torsion has no traumatic etiology. 1, 5