acute epididymitis

Last edited 06/2021 and last reviewed 06/2021

Acute epididymitis mostly occurs in young males. Organisms may reach the epididymis by retrograde spread from the prostatic urethra and seminal vesicles or less commonly, through the blood stream.

Predisposing factors include urinary tract infection, urethral instrumentation and sexually transmitted infection. E. coli and Chlamydia in patients with a history of urethral discharge are the organisms most frequently cultured

  • bacterial infections are the most common aetiology for epididymitis
    • in men <= 35 years of age, ascending infection from the urethra by sexually transmittable pathogens, namely Chlamydia trachomatis and Neisseria gonorrhoeae, are aetiologically responsible
    • in older men with a history of bladder outlet disturbances
      • Enterobacteriaceae, particularly Escherichia coli, represent the dominant pathogens
    • tuberculous epididymitis caused by mycobacteria must be considered as a differential diagnosis

Clinically, epididymitis may be indistinguishable from testicular torsion. Epididymo-orchitis denotes secondary involvement of the testis.

Possible complications include testicular atrophy and fibrotic obstruction of epididymal tubes leading to impaired fertility

Key points (3):

  • usually due to Gram-negative enteric bacteria in men over 35 years with low risk of STI
  • if under 35 years or STI risk, refer to GUM


  • noninfectious pathogenetic factors include (1):
    • systemic diseases like Behcet's disease
    • urethral manipulation
    • drug-induced sequelae (amiodarone),
    • blow-out injury of the epididymal duct following vasectomy and the reflux of sterile urine into the epididymes