Epididymitis is an infection of the epididymis. The epididymis is a soft, coiled tubular structure on the back of the testicle.

What is going on in the body?

Infections generally spread to the epididymis from the bladder or the urethra. The urethra is the tube that allows urine to pass from the bladder to the outside of the body. In young children or older men, bacteria that cause urinary tract infections are often the cause. Sexually transmitted diseases are more likely to be the cause in sexually active young men.

Infection in the epididymis causes severe pain and swelling. The infection may spread to the testicle. When both structures are inflamed, the condition is known as epididymo-orchitis. It is rare that an infection will occur in the testicle alone. The bacteria will usually infect the epididymis first.

What are the causes and risks of the disease?

Risk factors for epididymitis are the same as for infections of the urethra or bladder. These two conditions create an increased risk for epididymitis. Infections of the urethra are often sexually transmitted. These infections may be avoided by not having sex or using condoms during sex. Bladder infections are more common in those with inherited kidney and bladder problems. Bladder infections are also more common in those with enlarged prostate glands. Persons who need to use urinary catheters are at a higher risk for epididymitis. Urinary catheters are urine drainage tubes placed through the penis into the bladder.