- Inflammation (infectious or noninfectious) of epididymis resulting in scrotal pain and swelling, induration of the posterior epididymis, eventual scrotal wall edema, involvement of the adjacent testicle, and hydrocele formation
- Acute epididymitis: scrotal pain for <6 weeks
- Chronic epididymitis: scrotal pain for ≥6 weeks
- Epididymitis with involvement of testis is named epididymo-orchitis.
- Classification: infectious (bacterial, viral, fungal, parasitic) versus noninfectious (chemical, traumatic, autoimmune, idiopathic, industrial, noninfectious, vaso-epididymal reflux syndrome, vasal reflux syndrome); chronic versus acute
- System(s) affected: reproductive
- Predominant age: usually younger, sexually active men or older men with UTIs; in older men, commonly secondary to bladder outlet obstruction (i.e., benign prostatic hyperplasia [BPH])
- Predominant sex: male only
In prepubertal boys: Epididymitis is found to be the most common cause of acute scrotum—more common than testicular torsion.
- Common (600,000 cases annually in the United States) (1)
- 1 in 1,000 adult males per year
- 1.2 in 1,000 boys age 2 to 13 years per year (2),(3)
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 rather than infectious
- Can develop as a 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 be part of postinfectious syndrome from Mycoplasma pneumoniae, enterovirus, or adenovirus
- Henoch-Schönlein purpura may present as acute scrotum.
- 14 to 35 years of age
- Usually Chlamydia trachomatis (serous urethral discharge) or Neisseria gonorrhoeae (purulent discharge) in sexually active males
- With anal intercourse, likely Escherichia coli or Haemophilus influenzae
- >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 (4).
- Sterile urine reflux after transurethral prostatectomy
- Granulomatous reaction following BCG intravesical therapy for bladder cancer
- Amiodarone may cause noninfectious epididymitis; dose dependent and 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.
- 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
- 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
- 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
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Domino, Frank J., et al., editors. "Epididymitis." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2020. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116211/0.2/Epididymitis.
Epididymitis. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2020. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116211/0.2/Epididymitis. Accessed May 29, 2023.
Epididymitis. (2020). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (27th ed.). Wolters Kluwer. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116211/0.2/Epididymitis
Epididymitis [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2020. [cited 2023 May 29]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116211/0.2/Epididymitis.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Epididymitis ID - 116211 ED - Domino,Frank J, ED - Baldor,Robert A, ED - Golding,Jeremy, ED - Stephens,Mark B, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116211/0.2/Epididymitis PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -