Testicular Torsion

Risk factors

• Bell-clapper deformity (horizontal lie of testis; transverse fixation of tunica vaginalis on cord — present bilaterally in most cases)
• Cryptorchidism / undescended testis
• Prior intermittent torsion
• Trauma (in some cases — torsion can be spontaneous)
• Cold weather, exercise, sleep (cremaster contraction)
• Family history
• Increased testicular size (puberty)

Pathophysiology

Spermatic cord twists, occluding venous drainage first (more compressible), then arterial inflow → ischemia → infarction. Salvage rate strongly correlates with duration of torsion: ~95% at <6 hours, ~50% at 6-12 hours, <20% at >24 hours. Bilateral fixation prevents future torsion of contralateral testis.

Clinical presentation

Differential diagnosis

• Epididymitis / epididymo-orchitis — Gradual onset, fever, dysuria; positive Prehn sign (relief with elevation); preserved cremasteric reflex; older or sexually active patients
• Torsion of testicular/epididymal appendage — Younger boys (7-12 yo), localized tenderness at upper pole, 'blue dot sign'; self-limited
• Inguinal hernia (incarcerated/strangulated) — Mass extending into scrotum from inguinal canal
• Scrotal trauma (hematocele, testicular rupture) — Trauma history; ultrasound
• Henoch-Schönlein purpura with scrotal involvement — Palpable purpura, abdominal pain, arthralgia, hematuria
• Idiopathic scrotal edema — Bilateral edema, erythema; afebrile; self-limited; usually pre-pubertal
• Testicular tumor — Painless mass; can present with acute pain if hemorrhage; ultrasound
• Varicocele (acute) — 'Bag of worms,' more on left; usually painless or dull ache

Diagnostic workup

Diagnostic algorithm

flowchart TD
  A[Acute scrotal pain<br/>± nausea, vomiting] --> B[Focused exam:<br/>cremasteric reflex,<br/>testis lie, tenderness,<br/>Prehn sign]
  B --> C{High clinical<br/>suspicion for torsion?}
  C -->|High TWIST 5-7<br/>or classic exam| D[Urology STAT —<br/>OR for detorsion +<br/>bilateral orchiopexy]
  C -->|Intermediate<br/>TWIST 3-4| E[Color Doppler US]
  E -->|Decreased/absent flow| D
  E -->|Normal flow| F[Consider epididymitis,<br/>torsion of appendix,<br/>other causes]
  C -->|Low TWIST 0-2| F
  D --> G{Testis viable?}
  G -->|Yes| H[Detorse + bilateral<br/>orchiopexy 3-point fixation]
  G -->|No| I[Orchiectomy +<br/>contralateral orchiopexy]
  F --> J[Treat per diagnosis<br/>± antibiotics, NSAIDs,<br/>follow-up]

Treatment

Complications

• Loss of testis (orchiectomy)
• Subfertility / infertility — even after successful detorsion, sympathetic effects on contralateral testis can impair spermatogenesis
• Testicular atrophy after delayed detorsion
• Recurrent torsion if orchiopexy not performed
• Psychological impact on adolescent body image

PANCE pearls

• Testicular torsion is a SURGICAL EMERGENCY — call urology immediately and do not delay surgery for imaging if the diagnosis is clinically apparent.
• Salvage rate is >90% if detorsion occurs within 6 hours; <50% by 12 hours; <20% by 24 hours.
• Always examine the scrotum in any boy or young man with abdominal or groin pain — torsion can present with referred pain.
• Absent cremasteric reflex on the affected side is the most sensitive clinical finding for torsion in adolescents.
• Manual detorsion is rotated like 'opening a book' (laterally/outward) — but this is only a temporizing measure; surgical orchiopexy is still required.
• Bilateral orchiopexy at surgery is standard — bell-clapper deformity is usually bilateral.
• Suspect torsion in any neonate with a firm, discolored hemiscrotum from birth; in this age group most testes are nonviable, but contralateral fixation is important.
• Repeated self-resolving episodes of acute testicular pain (intermittent torsion) warrant elective bilateral orchiopexy.

References

• AUA — American Urological Association Medical Student Curriculum: Acute Scrotum (auanet.org)
• EAU 2024 — EAU Guidelines on Pediatric Urology — Acute Scrotum (2024)
• TWIST Score — Barbosa JA et al., Development and initial validation of a scoring system to diagnose testicular torsion in children (J Urol 2013;189:1859-64)
• TWIST validation — Sheth KR et al., Diagnosing Testicular Torsion before Urological Consultation and Imaging: Validation of the TWIST Score (J Urol 2016;195:1870-6)