Orchitis Workup

Updated: Jan 26, 2023
  • Author: Nataisia Terry, MD; Chief Editor: Erik D Schraga, MD  more...
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Approach Considerations

Epididymo-orchitis is a clinical diagnosis based on symptoms and signs. The history, eliciting genitourinary symptoms and the risk of exually transmitted infections (including anal intercourse), alongside examination findings and preliminary investigations, will suggest the most likely etiology and guide use of empiric antibiotics. Historically, sexually transmitted infections have been identified as the predominant cause for epididymitis in persons younger than 35 years, and enteric pathogens the primary cause in persons older than 35 years. Evidence to support this approach is limited; and age and sexual history are not sufficient for guiding antibiotic therapy alone. [19]



Laboratory Studies

Laboratory tests are often not helpful in making the diagnosis of orchitis in the ED. Diagnosing mumps orchitis can be comfortably made based on history and physical examination alone. Diagnosing mumps orchitis can be confirmed with serum immunofluorescence antibody testing.

In sexually active males, urethral cultures and gram stain should be obtained for Chlamydia trachomatis and N gonorrhoeae. Urinalysis and urine culture should also be obtained.

Obtaining a C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) may also be helpful, because elevations of these are more suggestive of inflammation associated with epididymo-orchitis. [22, 23]


Imaging Studies

Color Doppler ultrasonography has become the imaging test of choice for the evaluation of acute testicular pain. [2, 16, 17]

Because orchitis often presents as acute edema and pain of the testicle, ruling out testicular torsion is critical. A finding of a normal-sized testicle with decreased flow is suggestive of torsion, whereas a finding of an enlarged epididymis with thickening and increased flow is more suggestive of epididymitis/orchitis. [24]

Often, the history and physical examination are enough to make the diagnosis; however, as an adjunct, ultrasonography is highly sensitive for ruling out testicular torsion and for demonstrating inflammation of the testis or the epididymis. [25, 26]