Diagnostic Ultrasound - Abdomen and Pelvis

Epididymitis/Orchitis
Diagnoses: Scrotum
TERMINOLOGY
• Inflammation of epididymis &/or testis
IMAGING
• Test of choice: Color Doppler US; high frequency
transducers (9-15 MHz)
• Diffuse or focal hyperemia in body and tail of epididymis ±
increased vascularity of testis (compare with contralateral
testis if subtle)
• Starts within tail of epididymis → body → testis
• Orchitis is usually secondary, occurring in 20-40% of
epididymitis due to contiguous spread of infection
○ Can cause vascular compromise → ischemia → testicular
infarction → sonographic features indistinguishable from
testicular torsion
○ Reversal of arterial diastolic flow of testis is ominous
finding associated with testicular infarction
KEY FACTS
TOP DIFFERENTIAL DIAGNOSES
• Testicular torsion
• Testicular lymphoma
• Testicular trauma
CLINICAL ISSUES
• Commonest cause of acute scrotal pain in adolescent boys
and adults (15-35 years)
• Males 14 to 35 years of age: Most commonly caused by
Neisseria gonorrhoeae and Chlamydia trachomatis
• Scrotal swelling, erythema; fever; dysuria
○ Scrotal pain due to epididymitis is usually relieved after
elevation of testes (scrotum) over symphysis pubis
(Prehn sign)
○ Associated lower urinary tract infection and its
symptoms, urethral discharge
• Prognosis excellent if treated early with antibiotics; followup
scans to exclude abscess if no improvement
(Left) Graphic shows an
enlarged and inflamed
epididymis st enveloping the
testis posteriorly. Note that
the testis ſt appears normal
in size and configuration.
(Right) Graphic shows an
irregularly enlarged
epididymis ſt with focal cystic
areas st indicating early
liquefaction and necrosis.
(Left) Sagittal grayscale
ultrasound of the right
scrotum demonstrates a
thickened heterogeneous and
hypoechoic epididymis .
(Right) Color Doppler of the
epididymis in the same patient
reveals marked hyperemia
of the epididymis consistent
with acute epididymitis.
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