Summary
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.
Etiology
-
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
-
Urinary tract infections
-
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
Clinical features
-
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
Diagnostics
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
- Indicated
Differential diagnoses
- 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.
Treatment
- 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
Complications
- 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.