IntroductionAcute epididymo-orchitis (AEO) is an acute inflammatory disease of the epididymis and ipsilateral testis. Treatment should be started immediately after diagnosis and includes antibiotics, analgesics, and, if necessary, surgery.Materials and methodsAfter AEO diagnosis, patients were treated conservatively with analgesics and antibiotics. If no clinical improvement was observed within the first 48-72 hours of conservative treatment, patients underwent surgery. Depending on examination results, 254 patients (pts.) were divided into three groups: 1) with palpable differences between the epididymis and testis (E/T+), and without neither hydrocele, local softening (malacia), nor abscess of the epididymis or testis; 2) with E/T+, absence of malacia, presence of hydrocele, and none, one, or a few small abscesses within the epididymis/testis and 3) without palpatory differentiation between the epididymis and testis, with or without malacia, with hydrocele, and none, one, or more abscesses of any size. We analyzed the clinical outcomes in each group.ResultsAll of patients from the first group were successfully treated with antibiotics. In the second group, conservative treatment was effective in 70 pts. (85.4% of this group), but the other 12 pts. (14.6%) did not show clinical improvement and underwent organ-sparing surgery. The majority of patients from the third group did not demonstrate an objective response to antibacterial treatment during the first 48-72 hours and, therefore, underwent surgery. Based on examination results and clinical outcomes we developed a classification system for AEO, which divides AEO into three stages and recommends an approach to its treatment.ConclusionsOur classification is able to systematize treatment approaches in patients with AEO.