Epididymitis

Epididymitis is an inflammation of the epididymis that is commonly associated with genitourinary tract infections. The typical presentation involves a gradual onset of pain and swelling of the affected side of the scrotum as well as a positive Prehn sign. Epididymitis is a clinical diagnosis, but testicular torsion should be excluded by ultrasound because it has a similar presentation and is a surgical emergency. Treatment involves prompt empiric antibiotic therapy, scrotal elevation, and nonsteroidal anti‑inflammatory therapy to prevent abscess formation and possible infertility.

• Acute epididymitis: an inflammation of the epididymis, usually as a result of an infection
  • Urinary tract infections
    • Most common cause among older men and children
    • Pathogens: E. coli (most common), Pseudomonas (common), Proteus mirabilis, Klebsiella pneumoniae
  • Sexually transmitted infections
    • Most common cause among young males (usually < 35 years of age)
    • Pathogens: Chlamydia trachomatis; (common), Neisseria gonorrhoeae (common), Treponema pallidum, Trichomonas vaginalis, Gardnerella vaginalis
• Chronic epididymitis (> 6-week course of the disease)
  • Recurrent and/or untreated acute epididymitis
  • Tuberculosis (usually associated with renal tuberculosis)
  • Rare, noninfectious causes
    • Amiodarone-induced epididymitis
    • Autoimmune diseases (e.g., Behcet disease): associated with granuloma formation in seminiferous tubules

• Acute epididymitis
  • Unilateral scrotal pain and swelling; , which develops over several days and radiates to the ipsilateral flank ^[1]
  • Tenderness along the posterior testis.
  • Positive Prehn sign: reduced pain when the affected hemiscrotum is elevated
  • Scrotal skin overlying the epididymis may appear red, shiny, and edematous.
  • Low-grade fever (especially among children)
  • Symptoms of lower urinary tract infection (e.g., dysuria, frequency, urgency), including urethritis (urethral discharge)
• Chronic epididymitis
  • Recurrent bouts of scrotal pain
  • Swelling is minimal when compared to acute epididymitis
  • Thickened epididymis

Primarily a clinical diagnosis

• Laboratory findings ^[1]
  • Urinalysis (pyuria, bacteriuria) and urine culture if a UTI is suspected
  • Urethral swab for culture and nucleic acid amplification testing (Chlamydia, Gonorrhea) if an STI is suspected
  • CBC: leukocytosis
• Scrotal ultrasound
  • Indicated
    • To rule out testicular torsion if this is not possible based on history and physical exam
    • If an abscess is suspected
  • Findings in epididymitis: enlarged epididymis, increased blood flow

• Testicular torsion
• See “Differential diagnosis of scrotal pain.”
• Hydrocele
• Varicocele
• Inguinal hernia

Testicular torsion is the most important differential diagnosis of epididymitis and must be ruled out!

The differential diagnoses listed here are not exhaustive.

• Empiric antibiotic therapy based on likely pathogens (until the causative organism is known)
  • Suspected UTI (with enteric organisms): fluoroquinolones (e.g., ofloxacin, levofloxacin)
  • Suspected STI: (with chlamydia or gonorrhea) ceftriaxone PLUS doxycycline
  • In the case of Chlamydia, Gonorrhea, and enteric organisms: ceftriaxone PLUS fluoroquinolone
• Scrotal elevation, ice packs, and NSAIDs
• If an abscess develops: surgical drainage
• Chronic epididymitis
  • NSAIDs and prolonged antibiotic therapy
  • If symptoms persist: epididymectomy and/or orchidectomy
  • If tuberculosis is suspected: antituberculous therapy

• Epididymal abscess ^[2]
• Epididymo-orchitis: the spread of infection from the epididymis to the testicle
• Testicular infarction
• Infertility

We list the most important complications. The selection is not exhaustive.

1. Ludwig M. Diagnosis and therapy of acute prostatitis, epididymitis and orchitis. Andrologia. 2008; 40 (2): p.76-80.
2. Trojian TH, Lishnak TS, Heiman D. Epididymitis and orchitis: An overview. Am Fam Physician. 2009; 79 (7): p.583-587.