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Torsion of the Appendices and Epididymis Workup

  • Author: Jason S Chang, MD; Chief Editor: Erik D Schraga, MD  more...
Updated: Dec 12, 2014

Laboratory Studies

See the list below:

  • Urinalysis
  • CBC with differential

Imaging Studies


Testicular appendage torsion appears as a lesion of low echogenicity with a central hypoechogenic area.

The presence of a large appendix adjacent to the epididymis (in the absence of clinically detectable inflammation) may signify testicular involvement.

If the edematous appendix and the head of the epididymis are close enough, this condition will have the "Mickey Mouse" appearance on transverse view.

Ultrasonography can be useful in distinguishing torsion of a testicle and torsion of an appendix testis.

In a retrospective study of 241 boys with acute scrotal pain, the best predictors for epididymitis were dysuria, a painful epididymis on palpation, and altered epididymal echogenicity and increased peritesticular perfusion on ultrasound studies; for appendix testis (AT), the best predictor was a positive blue dot sign.[6]

Color Doppler ultrasonography

Color Doppler sonography (CDS) is the imaging modality of choice for evaluation of the acute scrotum.[7]

In torsion of the testicular appendage, CDS shows normal blood flow to the testis, with an occasional increase on the affected side that possibly is due to inflammation.

In prepubertal patients, this method of imaging is somewhat controversial because the prepubertal testis has low-velocity blood flow, and CDS is less accurate in these instances.

Some studies suggest that CDS has 90% sensitivity and 98% specificity in diagnosing acute testicular torsion. However, variability exists in the sensitivity of color Doppler ultrasonography. As a result, a negative ultrasonographic result does not necessarily exclude testicular torsion.

A study by Pepe et al demonstrated that CDS specificity may not be as high as previously reported for testicular torsion.[8] In a subset analysis of 42 adolescents with diagnostic suspicion of testicular torsion by CDS, only 22 had surgical confirmation of this diagnosis, while 16 were found to be normal and 4 had torsion of the testicular appendage. In fact, clinical examination alone had sensitivity and specificity of 100% and 50%, respectively, while CDS had sensitivity and specificity of 95.7% and 48.7%, respectively. In a patient presenting with an acute scrotum, a negative CDS result may provide supportive evidence that the patient has a benign condition like torsion of an appendage, but it does not exclude the diagnosis of testicular torsion. In high clinical suspicion, surgical exploration may still be warranted.

Radionuclide imaging

The positive sign for testicular appendix torsion is the hot-dot sign, which is an area of increased tracer uptake. This sign is pathognomonic for testicular appendix torsion. Radionuclide images do not show a positive result if symptoms have been present for fewer than 5 hours. Positive results are seen in only 45% of patients whose symptoms have lasted 5-24 hours.[9] The test is reported to be 68% sensitive and 79% accurate.[9]

Contributor Information and Disclosures

Jason S Chang, MD Clinical Instructor, Department of Emergency Medicine, University of Pittsburgh Medical Center

Jason S Chang, MD is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, Society for Academic Emergency Medicine, Emergency Medicine Residents' Association

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Richard H Sinert, DO Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, Research Director, State University of New York College of Medicine; Consulting Staff, Vice-Chair in Charge of Research, Department of Emergency Medicine, Kings County Hospital Center

Richard H Sinert, DO is a member of the following medical societies: American College of Physicians, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Erik D Schraga, MD Staff Physician, Department of Emergency Medicine, Mills-Peninsula Emergency Medical Associates

Disclosure: Nothing to disclose.

Additional Contributors

Theodore J Gaeta, DO, MPH, FACEP Clinical Associate Professor, Department of Emergency Medicine, Weill Cornell Medical College; Vice Chairman and Program Director of Emergency Medicine Residency Program, Department of Emergency Medicine, New York Methodist Hospital; Academic Chair, Adjunct Professor, Department of Emergency Medicine, St George's University School of Medicine

Theodore J Gaeta, DO, MPH, FACEP is a member of the following medical societies: American College of Emergency Physicians, New York Academy of Medicine, Society for Academic Emergency Medicine, Council of Emergency Medicine Residency Directors, Clerkship Directors in Emergency Medicine, Alliance for Clinical Education

Disclosure: Nothing to disclose.


The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous authors, Sean O Henderson, MD, and Gregory Alfred, MD, to the development and writing of this article.

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