By Nicholas Otts, MD
Edited by Gal Altberg, MD and Abbas Husain, MD
A Common Problem:
11 year old male complaints of two episodes of testicular pain associated with nausea and vomiting, but in the emergency department the pain resolved. His testicular exam is non contributory. Ultrasound of his scrotum shows increased flow to left testicle. Torsion ruled out?
A Small Dose of EBM:
Testicular torsion has a bimodal distribution - initial peak during first year of life followed by the pubertal surge in adolescence; thus, torsion is primarily a PEM problem. Classically, ED residents are taught to evaluate torsion with an ultrasound, using power doppler to assess flow to involved testicle. If no or decreased flow compared to other side, there is a much higher concern for torsion.
What about normal or even increased flow? Does that rule out torsion? What if pain has resolved. What about intermittent torsion?
Intermittent testicular torsion, in which the spermatic cord twists and spontaneously resolves, is often a harbinger of final torsion. It is a problem that needs surgical correction, and, thus a diagnosis that cannot be missed.
On ultrasound, however, it can look like other causes of testicular pain. With flow returned to the testicle, the subsequent inflammation can appear as increased flow on doppler, which can be mistaken for orchitis. Further, the epididymis, near the spermatic cord, is often inflamed with or without return of flow, appearing enlarged and hyperemic on ultrasound, leading one to possibly suspect epididymitis.
Enter the Whirlpool
Whirlpool sign on ultrasound is another marker of torsion, and is created by a twisting of the spermatic cord (1,2,3). A good retrospective study at Texas Children’s showed that in patients with a surgical diagnosis of intermittent torsion, the whirlpool sign on ultrasound is a significant marker and can help distinguish this from other causes of testicular pain when doppler is non-diagnostic (4).
So, the next time you suspect torsion, think about intermittent torsion and make sure the ultrasound evaluation includes a good examination of the spermatic cord.
A good article with video of whirlpool sign:
1. Vijayaraghavan SB. Sonographic differential diagnosis of acute scrotum: real-time whirlpool sign, a key sign of torsion. J Ultrasound Med 2006; 25:563-574
2. Baud C, Veyrac C, Couture C, Ferran JL. Spiral twist of the spermatic cord: a reliable sign of testicular torsion. Pediatr Radiol. 1998;28:950–954
3. Esposito F, Di Serafino M, Mercogliano C, Vitale V, Sgambati P, Vallone G. The “whirlpool sign”, a US finding in partial torsion of the spermatic cord: 4 cases. Journal of Ultrasound. 2014;17(4):313-315.
4. Munden MM, Williams J, et. al. Intermittent Testicular Torsion in the Pediatric Patient: Sonographic Indicators of a Difficult Diagnosis. American Journal of Roentgenology. 2013;201: 912-91