Epididymo-orchitis is an inflammation of the testis and epididymis, generally of infectious origin. In young men epididymo-orchitis is most often associated with sexually transmitted infections. In those aged over 35 the causative pathogens are more likely to be non-sexually transmitted coliform organisms associated with urinary tract infections. Other causes include viral infections such as mumps in immunocompromised, non-immunised or prepubescent males, local trauma, and medication such as amiodarone.