Epididymo-orchitis

• Epididymo-orchitis is the clinical syndrome of pain and swelling of the epididymis and testis which occurs in the context of a urethral or a urinary tract infection.
• In sexually active men aged 14 – 35 the causative organisms are most commonly Chlamydia trachomatis and Neisseria gonorrhoeae, however men who have insertive anal sex may also acquire enteric Gram-negative bacteria (such as E. Coli).
• There is weak evidence for the causative role of Mycoplasma genitalium.
• In younger and older age groups the causative organisms are more likely to be enteric Gram-negative bacteria. 
• Epididymo-orchitis can also be secondary to a number of other bacterial infections (such as syphilis and tuberculosis) and viral infections (mumps) but this is seen uncommonly in our clinic. 

• Typically there is unilateral swelling and tenderness of the epididymis which feels indurated on palpation. 
• In milder infections there may be no involvement of the testis while in more severe infections, or viral orchitis, the testes are also involved.
• The presence of urethral or lower urinary tract symptoms, systemic symptoms and a more gradual onset helps to distinguish epididymo-orchitis from torsion of the testis, but differentiation is frequently difficult and the clinician needs to have a low threshold for referral. 
• Differential diagnosis includes:
  • Testicular torsion
  • Torsion of epididymal appendage
  • Trauma
  • Hydrocoele
  • Epididymal cyst
  • Testicular tumour
• Testicular torsion is a surgical emergency which should be considered in all patients with a painful scrotum.
  • It most commonly occurs in males under the age of 20 but can occur at any age. 
  • If testicular torsion is suspected, the patient should be referred to an emergency department for urgent surgical assessment.  
  • An ultrasound scan with Doppler is helpful diagnostically but should not delay surgical assessment.

Epididymo-orchitis is a clinical diagnosis, sometimes confirmed on ultrasound scan.

Index patient

• Antibiotic treatment depends on the presumed source of infection and should aim to cover the most likely bacterial pathogens.
• Simple analgesics, scrotal support, limitation of activity, and use of cold packs can be helpful.
• Patients with acute epididymo-orchitis on appropriate treatment should generally improve within 48 to 72 hours.
• If there is no improvement the diagnosis should be re-evaluated or referral considered.