Description

• Inflammation (infectious or noninfectious) of the epididymis resulting in scrotal pain and swelling, induration of the posterior epididymis, involvement of the adjacent testicle, and possible hydrocele formation
• Acute epididymitis: scrotal pain for <6 weeks
• Chronic epididymitis: scrotal pain for ≥6 weeks
• Epididymitis with involvement of the testis is named epididymo-orchitis.
• Classification: infectious (bacterial, viral, fungal, parasitic) versus noninfectious (chemical, traumatic, autoimmune, idiopathic, industrial, vaso-epididymal reflux syndrome)
• System(s) affected: reproductive

Epidemiology

• Predominant age: generally younger, sexually active men or older men with UTIs and bladder outlet obstruction (e.g., benign prostatic hyperplasia [BPH])
• Predominant sex: male only

Pediatric Considerations
Epididymitis is found to be the most common cause of acute scrotal pain in prepubertal boys—more common than testicular torsion.

Incidence

• Common (600,000 cases annually in the United States) (1)
• 1 in 1,000 adult males per year
• 1.2 in 1,000 boys aged 2 to 13 years per year (2),(3)

Prevalence
Common

Etiology and Pathophysiology

• Infectious epididymitis
  • Retrograde passage of urinary bacteria from the prostate or urethra to the epididymis via the ejaculatory ducts and the vas deferens; rarely, hematogenous spread
  • Causative organism is identified in 80% of patients and varies according to patient age.
• Noninfectious epididymitis
  • Often, no etiology is found; however, can be instigated by trauma, autoimmune disease, or vasculitis
  • Likely secondary to reflux of sterile urine causing a chemical inflammation
  • Can develop as sequelae of strenuous exercise with a full bladder when urine is pushed through internal urethral sphincter (located at proximal end of prostatic urethra) or prolonged periods of sitting
  • Reflux of urine through orifice of ejaculatory ducts at verumontanum may occur with history of urethritis/prostatitis because inflammation may produce rigidity in musculature surrounding orifice to ejaculatory ducts, holding them open.
  • Exposure of epididymis to foreign fluid may produce inflammatory reaction within 24 hours.
• <14 years of age
  • Cause largely unknown, although likely from anatomic abnormalities resulting in urine reflux such as vesicoureteral reflux, ectopic ureter, or anorectal malformation (rectourethral fistula)
  • May also result from postinfectious syndrome from Mycoplasma pneumoniae, enterovirus, or adenovirus
  • Henoch-Schönlein purpura may present as acute scrotal pain.
• 14 to 35 years of age
  • Usually Chlamydia trachomatis, Neisseria gonorrhoeae, or Mycoplasma genitalium in sexually active males
  • With anal intercourse, likely enteric pathogens (e.g., Escherichia coli)
• >35 years
  • Commonly enteric bacteria but occasionally Staphylococcus aureus or Staphylococcus epidermidis
  • In elderly men, often with distal urinary tract obstruction, BPH, UTI, or catheterization
  • Tuberculosis (TB), if sterile pyuria, nodularity of vas deferens (hematogenous spread), and recent infection. TB is the most common granulomatous disease affecting the epididymitis.
  • Sterile urine reflux after transurethral prostatectomy
  • Granulomatous reaction following BCG intravesical therapy for bladder cancer
• Amiodarone may cause a dose-dependent noninfectious epididymitis; usually resolves with decreasing drug dosage (<200 mg/day)
• Syphilis, blastomycosis, coccidioidomycosis, and cryptococcosis are rare causes, but brucellosis can be a common cause in endemic areas.

Risk Factors

• UTI
• Prostatitis
• Indwelling urethral catheter
• Urethral instrumentation or transurethral surgery
• Urethral or meatal stricture
• Transrectal prostate biopsy
• Prostate brachytherapy (seeds) for prostate cancer
• Anal intercourse
• High-risk sexual activity
• Strenuous physical activity
• Prolonged sedentary periods
• Bladder obstruction (BPH, prostate cancer)
• HIV-immunosuppressed patient
• Severe Behçet disease
• Presence of foreskin
• Constipation
• Increased intra-abdominal pressure (due to frequent physical strain)
  • Military recruits, especially who begin physically unprepared
  • Laborers; restaurant kitchen workers
  • Full bladder during intense physical exertion

General Prevention

• Safer sexual practices
• Mumps vaccination
• Antibiotic prophylaxis for urethral manipulation
• Early treatment of prostatitis/BPH
• Vasectomy or vasoligation during transurethral surgery
• Avoid vigorous rectal exam with acute prostatitis.
• Emptying the bladder prior to physical exertion
• Physically conditioning the body prior to engaging in regular intense physical exertion
• Treat constipation.

Commonly Associated Conditions

• Prostatitis/urethritis/orchitis
• Hematospermia
• Constipation
• UTI