What is the difference between epididymitis and testicular torsion?

Distinguishing Epididymitis from Testicular Torsion

Testicular torsion is a surgical emergency requiring intervention within 6-8 hours, while epididymitis is an inflammatory condition managed conservatively—the key differences lie in onset timing, age distribution, pain characteristics, and physical examination findings. 1

Critical Distinguishing Features

Onset and Timing of Pain

• Testicular torsion presents with abrupt, sudden onset of severe scrotal pain, whereas epididymitis develops gradually over hours to days 1
• Patients with epididymitis typically have an average pain duration of 4.5 days at presentation, compared to only 19.1 hours in testicular torsion 2
• The sudden onset is one of the most reliable clinical indicators—when pain is sudden and severe without evidence of urethritis or UTI, emergency testing for torsion is indicated 1

Age Distribution

• Testicular torsion has a bimodal distribution with peaks in neonates and postpubertal boys (ages 12-18 years), though it can occur at any age 3, 1
• Epididymitis is most common in adults over 25 years of age 1
• The mean age for epididymitis patients is significantly higher (40.7 years) compared to torsion (13.8 years) 2

Physical Examination Findings

• A negative Prehn sign (pain NOT relieved with testicular elevation) strongly suggests testicular torsion, while pain relief with elevation suggests epididymitis 1
• The absence of a cremasteric reflex is a key finding in testicular torsion 4, 5
• Testicular torsion may present with a high-riding testicle 5
• Epididymitis is more commonly associated with evidence of inflammation or infection 1

Diagnostic Evaluation

Ultrasound Findings

• Duplex Doppler ultrasound is the first-line imaging modality with sensitivity of 96-100% for testicular torsion 1
• Testicular torsion shows decreased or absent blood flow to the affected testicle on color Doppler assessment 1, 6
• The "whirlpool sign" (spiral twist of the spermatic cord) is the most specific ultrasound finding for torsion with 96% sensitivity 3, 1
• Testicular torsion also shows an enlarged, heterogeneous, hypoechoic testis with possible ipsilateral hydrocele and scrotal skin thickening 1
• Epididymitis typically shows increased blood flow on Doppler ultrasound 1

Important Caveat

• A normal ultrasound cannot exclude testicular torsion—false-negative Doppler evaluations can occur with partial torsion or spontaneous detorsion 1, 4
• The accuracy of ultrasonography for testicular torsion is only 72.7% in some series, emphasizing that clinical suspicion should drive management 2

Management Algorithm

When Testicular Torsion is Suspected

• Immediate urological consultation and prompt surgical exploration is the definitive treatment—do not delay surgery to obtain imaging if clinical suspicion is high 1, 5
• Surgical detorsion must occur within 6-8 hours of symptom onset to prevent permanent ischemic damage and testicular loss 3, 1, 6
• The orchiectomy rate is 42% in boys undergoing surgery for testicular torsion when treatment is delayed 5

When Epididymitis is Diagnosed

• Conservative management with antibiotics, bed rest, scrotal elevation, and analgesics until inflammation subsides 1
• The majority (87.5%) of epididymitis patients can be managed conservatively 2

Clinical Decision-Making Tool

• The TWIST (Testicular Workup for Ischemia and Suspected Torsion) score can assist with risk stratification 1, 4
• For intermediate clinical suspicion (TWIST score 1-5), urgent Duplex Doppler ultrasound is recommended 1
• However, the TWIST score should not be used in isolation and should not delay surgical consultation when torsion is suspected 4

Common Pitfalls to Avoid

• Do not mistake testicular torsion for epididymitis and initiate antibiotic therapy—this delays definitive surgical treatment and can result in testicular loss 7
• Two adult patients in one series were initially treated with antibiotics for suspected epididymitis, and one required orchidectomy due to necrosis 7
• Do not rely solely on the presence or absence of cremasteric reflex—while helpful, it is not completely reliable 4
• Remember that testicular torsion, though uncommon in adults, can occur at any age and should always be considered in the differential diagnosis 7, 5