Testicular torsion, i.e. torsion of the spermatic cord, is relatively common and its end-result is the obstruction of the arterial blood supply to the testis. A prompt diagnosis is important for saving the testis. However, atypical presentations of testicular torsion may delay recognition of the condition. We must also differentiate between this and other causes of an acute scrotum. Diagnostic imaging, particularly Doppler ultrasonography, plays an important role in the assessment of the patient with acute scrotal pain.

The differential diagnosis includes:

• epididymo-orchitis
• torsion of the testicular appendages
• trauma

The ability to rapidly distinguish between these possibilities is important because the morbidity of testicular ischemia is high and there is a need to institute appropriate treatment.

Twisting of the spermatic cord usually first causes venous, then later arterial flow obstruction. The amount of testicular necrosis depends on the duration and degree of torsion. Torsion of greater than 6 hours usually results in a non-viable testis.

Whirlpool sign is highly reliable for the direct diagnostic confirmation of testicular torsion, especially with the presence of vascular flow in the testis with torsion-detorsion twisting.