The epididymis is a coiled tube. It is part of the male reproductive system. A man’s two testicles sit inside the scrotum. One epididymis sits behind each testicle. Epididymitis is inflammation (swelling and irritation) of this tube. Orchitis occurs when the inflammation spreads to the testicle.
Sperm are made in the testicles. Sperm travel from the testicles through the epididymis. They flow into a tube called the vas deferens. During ejaculation, sperm pass from the vas deferens through the urethra out of the body. During urination, urine flows from the bladder through the urethra out of the body.
The problem is thought to be due to bacteria. If bacteria get into the urethra, they may cause an infection. Infection can then travel up the urethra into the epididymis. This leads to inflammation. Pain and swelling can then spread to the testicle. This is called orchitis. In rare cases, orchitis can be due to an infection with the mumps virus. There are two kinds of inflammation:
Acute inflammation comes on quickly. Symptoms may include:
Pain and swelling in the scrotum
Frequent urge to urinate
Discharge from the penis
Pain during ejaculation
Chronic inflammation is most often the late phase of an acute infection. Symptoms may include:
An ache or dull pain in the scrotum, which may spread to the groin
A heavy feeling in the scrotum