What causes testicular torsion in an infant?

Causes of Testicular Torsion in Infants

In infants, testicular torsion is primarily caused by an extravaginal twisting of the spermatic cord that often occurs prenatally or perinatally, compromising blood flow to and from the testicle. 1, 2

Types and Timing of Testicular Torsion in Infants

• Perinatal testicular torsion is uncommon, accounting for approximately 10% of testicular torsion cases in children 1
• Testicular torsion has a bimodal distribution, occurring more frequently in neonates and postpubertal boys than in adults, although it can occur at any age 1
• In infants, torsion is typically extravaginal (occurring outside the tunica vaginalis), unlike the intravaginal torsion seen in older children and adults 2
• Many cases of infant testicular torsion occur prenatally (in utero) and are already present at birth 3

Anatomical Factors Contributing to Infant Testicular Torsion

• The primary cause is the incomplete fixation of the testis and spermatic cord to the scrotal wall in neonates 2
• Unlike older children who often have a "bell-clapper deformity" (abnormal tunica vaginalis attachment), infants experience torsion due to increased mobility of the entire testis and spermatic cord within the scrotum 4, 5
• The lack of scrotal attachments in the perinatal period allows the entire testicle, including the tunica vaginalis, to rotate freely 2

Clinical Presentation and Diagnosis

• Most common clinical signs include a hardened and enlarged testicle with discoloration of the scrotum 2
• Ultrasound findings typically show abnormal size or echostructure of the affected testicle and absence of blood flow on Doppler examination 2
• The "whirlpool sign" (spiral twist of the spermatic cord) is the most specific ultrasound sign of torsion 1
• Bilateral torsion is being more frequently reported in neonates, with the possibility of metachronous contralateral torsion 6

Prognosis and Management Considerations

• Prenatal testicular torsion often represents an irreversible intrauterine event by the time it is diagnosed 3
• Immediate surgical intervention is recommended when testicular torsion is suspected in an infant 4
• The salvage rate for the affected testicle depends on the degree of torsion and duration of ischemia 1
• Surgical exploration within 6-8 hours of symptom onset is essential to prevent testicular loss in cases of acute torsion 1, 4
• In cases of prenatal torsion discovered at birth, many experts recommend contralateral orchiopexy to prevent future torsion of the unaffected testicle 3

Diagnostic Challenges

• Assessment of the contralateral testis through physical examination and imaging can be inaccurate in cases of perinatal torsion 6
• Ultrasound elastography may be useful in assessing testicle structure and hardening of the necrotic testicle 2
• Differential diagnosis includes epididymitis, strangulated inguinal hernia, traumatic hematoma, and testicular tumor 5