Orchitis is an acute inflammatory reaction of the testis secondary to infection. While the more common epididymo-orchitis is bacterial in origin, isolated orchitis usually has a viral etiology. This condition rarely occurs in postpubertal males with mumps.
Bacterial orchitis is even more rare, and it usually is associated with a concurrent epididymitis.
Sterility is rarely a consequence of unilateral orchitis. Despite some anecdotal reports, there is little evidence supporting an increased likelihood of developing a testicular tumor after an episode of orchitis. Orchitis is characterized by testicular pain and swelling. The course is variable and ranges from mild discomfort to severe pain. A sexual history should be obtained, when appropriate.