Orchitis can be caused by either a bacterial or viral infection.

Bacterial orchitis

Most often, bacterial orchitis is the result of epididymitis, an inflammation of the coiled tube that connects the vas deferens and the testicle. The vas deferens carries sperm from your testicles. When inflammation in the epididymis spreads to the testicle, the resulting condition is known as epididymo-orchitis.

Epididymitis usually is caused by an infection of the urethra or bladder that spreads to the epididymis. Often the cause of the infection is a sexually transmitted infection (STI), particularly gonorrhea or chlamydia. Other causes of infection may be related to having been born with abnormalities in your urinary tract or having had a catheter or medical instruments inserted into your penis.

Viral orchitis

Most cases of viral orchitis are the result of the mumps virus. About one-third of males who contract the mumps after puberty develop orchitis during their course of the mumps, usually four to seven days after onset.

Oct. 07, 2011