Epididymo-orchitis

Epididymo-orchitis describes an infection of the epididymis +/- testes resulting in pain and swelling. It is most commonly caused by local spread of infections from the genital tract (such as Chlamydia trachomatis and Neisseria gonorrhoeae, typically seen in sexually active younger adults) or the bladder (E. coli, typically seen in older adults with a low-risk sexual history).

Features

• unilateral testicular pain and swelling
• urethral discharge may be present, but urethritis is often asymptomatic
• factors suggesting testicular torsion include patients < 20 years, severe pain and an acute onset

The most important differential diagnosis is testicular torsion. This needs to be excluded urgently to prevent ischaemia of the testicle.

Investigations are typically guided by the age of the patient

• in younger adults assess for sexually transmitted infections (STI)
• in older adults with a low-risk sexual history send a mid-stream urine (MSU) for microscopy and culture

Management

• if an STI is the most likely cause advise urgent referral to a local specialist sexual health clinic
  • if the organism is unknown BASHH recommend: ceftriaxone 500mg intramuscularly single dose, plus doxycycline 100mg by mouth twice daily for 10-14 days
• if enteric organisms are the most likely cause
  • send an MSU as above
  • treating empirically with an oral quinolone for 2 weeks (e.g. ofloxacin)
• further investigations following treatment may be recommended to exclude any underlying structural abnormalities