• Sudden twisting of the spermatic cord within the scrotum.

Epidemiology: peak incidence neonates and adolescent boys.

Aetiology: idiopathic, iatrogenic, following trauma.

Risk factors: <25 years, bell clapper deformity (allows testicles to rotate freely within the tunica vaginalis), trauma, undescended testicle, colder weather.

Pathogenesis: sudden twisting of spermatic cord → venous engorgement and arterial compromise → tissue ischaemia → irreversible damage after 6-12 hours.

Clinical features:

• Sudden onset severe testicular pain with associated nausea and vomiting.
• may radiate to thigh/iliac fossa
• can be painless in neonates
• Swollen, tender and elevated testicle.
• tender, thickened spermatic cord
• red/blue discolouration (dark in neonate)
• Absent cremasteric reflex.
• impaired gait

Investigations: typically a clinical diagnosis, imaging should not delay management.

• Duplex USS of scrotum: twisting of spermatic cord (whirlpool sign), reduced or absent blood flow to affected testis.

Treatment:

• Immediate surgical exploration of scrotum, and reduction and orchidopexy of the affected testis.
• Manual detorsion may be attempted for pain relief if surgery is not immediately available.
• Supportive care → analgesia, antiemetics.

Complications: testicular necrosis, infertility secondary to loss of testicle, psychological implications of losing a testis, recurrent torsion, impaired pubertal development.