Snapshot A 20-year-old man presents with left-sided testicular pain and swelling. He has a past medical history of multiple sexually transmitted infections. On physical exam, his left scrotum and testicle are erythematous, indurated, and tender to palpation. An ultrasound reveals a thickened epididymis. He is sent to the lab for testing for sexually transmitted diseases. Introduction Clinical definition inflammation of epididymis with symptoms of < 6 weeks Epidemiology incidence 25 per 100,000 persons demographics men 18-35 years old risk factors sexual activity bladder outlet obstruction Etiology pathogens from sexually transmitted infections in men less than 35 years of age Neisseria gonorrhoeae Chlamydia trachomatis urinary tract pathogens in men greater than 35 years of age Escherichia coli Pathogenesis consequence of sexually transmitted disease or urinary tract infection retrograde ascent of pathogen bladder outlet obstruction bacteriuria and subsequent retrograde ascent of pathogen Prognosis resolves with antibiotics Presentation Symptoms testicular pain and often unilateral lower abdominal pain urinary frequency or urgency urinary dysuria Physical exam fever testicular erythema, tenderness, and induration cremasteric reflex intact Prehn's sign decrease in pain with scrotal elevation Imaging Ultrasound indications to rule out testicular torsion findings enlarged and thick epididymis increased blood flow may also find reactive hydrocele Studies Urine positive leukocyte esterase 10 or more wbc/hpf nucleic amplification testing for Chlamydia and Neisseria Differential Testicular torsion absent cremasteric reflex Treatment Medical antibiotics guided by sexual and urologic history ceftriaxone and doxycycline for sexually transmitted diseases fluoroquinolone for enteric pathogens Complications Sepsis Testicular atrophy