- Usual presentation of acute epididymitis is unilateral testicular pain and tenderness of gradual onset +/- symptoms of urethritis or urethral discharge.

- Important to rule out torsion of testis (surgical emergency) or tumour.

Etiology:

- Acute epididymitis may be caused by many different infectious organisms and a few noninfectious causes.

- The etiology of bacterial epididymitis is largely dependent on age, sexual practices, and the presence of urinary tract abnormalities or history of instrumentation.

- There has been a shift in age distribution, causative organism, and the importance of sexual activity on the etiology of epididymitis:

Among sexually active men of all ages, STI pathogens including Chlamydia trachomatis and Neisseria gonorrhoeae are common causes of epididymitis.
Mycoplasmoides genitalium (previously Mycoplasma genitalium) is now increasingly recognized as an important cause of epididymitis.
In addition, men who are the insertive partner during anal intercourse may also develop acute epididymitis from enteric organisms (e.g. Escherichia coli ).
In older men (>35 years), infection may be due to nonsexually transmitted infection with common uropathogens, such as Escherichia coli and Proteus sp and associated with other risk factors, such as bladder outlet obstruction, recent instrumentation of the urinary tract, or systemic illness.

- Half of all STI pathogens are detected in sexually active men who do not report high-risk sexual practices. It is therefore important to screen all sexually active men with epididymitis for STI pathogens.

Epididymo-orchitis