result of descending infection caused by urinary tract pathogens
When the infection involves the epididymis and testis (epididymo-orchitis), sonography will frequently show an enlarged heterogeneous testis with increased color flow.
In sexually active men under age 35, acute epididymitis is caused most frequently by Chlamydia trachomatis and less commonly by Neisseria gonorrhoeae.
Clinical features suggestive of urethritis may be absent (subclinical urethritis). Epididymitis in men who have practiced unprotected insertive rectal intercourse is often caused by Enterobacteriaceae.
These men usually do not have urethritis but do have bacteriuria. Treatment of acute epididymo-orchitis consists of administering appropriate antibiotics for the treatment of both gonorrhea and Chlamydia infections.
Testicular Torsion
Unilateral absent flow on color and spectral Doppler sonography is a highly sensitive and specific finding
Heterogeneous echotexture of the testis is a common finding in sonograms performed to evaluate acute scrotal pain, regardless of the cause.