In epididymo-orchitis, the epididymis (the coiled tube that runs along the back of the testis and stores sperm, which then pass to the vas deferens) and testis become inflamed, causing pain and swelling at the back of the testis and, in severe cases, swelling, redness, and extreme pain in the scrotum. It is usually one-sided.
An inflammation that only affects the epididymis is called epididymitis.
Inflammation of the testis is called orchitis. Orchitis may cause swelling and pain in one or both testes, fever, nausea, and vomiting.
Epididymo-orchitis, epididymitis, and orchitis are usually caused by a sexually transmitted disease, such as chlamydia infection or nongonococcal urethritis , or a urinary tract infection rarely, it is due to an infection carried through the bloodstream from elsewhere in the body, such as tuberculosis . Treatment is with medication
