Definition of Orchitis:

Orchitis is an inflammation of one or both of the testicles, often caused by infection.

Causes, incidence, and risk factors:

Orchitis may be caused by number of different types of bacteria and viruses. It is usually a result of epididymitis, inflammation of the tube that connects the vas deferens and the testicle.

The most common viral cause of orchitis is mumps. Approximately 30% of patients who have mumps will develop orchitis during the course of the illness. It is most common in boys past puberty, and rare before the age of 10. It usually develops 4 to 6 days after the mumps occur. In one-third of boys who get orchitis caused by mumps, testicular atrophy (shrinking of the testicles) will result.

Orchitis develops in 2 - 20% of men with the rare disease brucellosis.

Orchitis may also occur along with infections of the prostate or epididymis and may occur as a result of sexually-transmitted diseases (STD) such as gonorrhea or chlamydia. The rate of sexually-transmitted orchitis or epididymitis is higher in men 19 to 35 years old.

Risk factors for non-sexually-transmitted orchitis include:

• Inadequate immunization against mumps
• Being older than age 45
• Recurrent urinary tract infections
• Congenital problems of the urinary tract
• Genito-urinary surgery
• Long term use of a Foley catheter (tube inserted into the bladder to drain urine)

Risk factors for sexually-transmitted orchitis include:

• Multiple sexual partners
• Other high risk sexual behaviors.
• History of a sexual partner with a previously diagnosed STD
• Personal history of gonorrhea or other STD