What is epididymitis?

What is Epididymitis

Epididymitis is an inflammation of the epididymis that typically presents with unilateral testicular pain and tenderness, accompanied by palpable swelling of the epididymis and often a hydrocele. 1

Pathophysiology and Route of Infection

• Epididymitis occurs when pathogens reach the epididymis primarily through retrograde ascent through the vas deferens, making it the most common route of infection 2, 3
• This represents the most common intrascrotal inflammation and accounts for approximately 400 cases per 100,000 men annually 4, 3
• The condition affects men across all age groups, with a frequency peak between 20 and 40 years of age 2

Age-Specific Causative Organisms

Men <35 Years (Sexually Active)

• Chlamydia trachomatis and Neisseria gonorrhoeae are the predominant pathogens in this age group 5, 6, 7
• Sexually transmitted epididymitis usually accompanies urethritis, which is often asymptomatic 5
• Among men tested in emergency departments, chlamydia (12.3%) was more common than gonorrhea (3.1%) 7

Men Who Practice Insertive Anal Intercourse

• Enteric organisms (particularly Escherichia coli) are common causative agents in addition to sexually transmitted pathogens 5, 6
• This occurs due to sexually transmitted enteric organisms 5

Men >35 Years

• Gram-negative enteric organisms (especially E. coli) are the primary pathogens 5, 6
• These infections typically result from reflux of urine into the ejaculatory ducts secondary to bladder outlet obstruction 6, 2
• Underlying urinary tract abnormalities or recent urinary instrumentation are frequently present 5, 2

Children <14 Years

• The etiology is largely unknown, but reflux of urine into the ejaculatory ducts is considered the most common mechanism 6

Clinical Presentation

• Gradual onset of unilateral posterior scrotal pain is the hallmark symptom 1, 6
• Palpable swelling of the epididymis with the testis in an anatomically normal position 1, 6
• Hydrocele may be present 1
• Urinary symptoms such as dysuria and urinary frequency may accompany the pain 6
• Fever may occur in more severe cases 1

Critical Differential Diagnosis

Testicular torsion is a surgical emergency that must be excluded in all cases of acute scrotal pain 5, 1:

• Torsion occurs more frequently in adolescents and presents with sudden onset of severe pain 1
• It is more common in patients without evidence of inflammation or infection 5
• Emergency consultation with a specialist is indicated when the diagnosis is questionable, as testicular viability may be compromised 5, 1

Other important differentials include testicular infarction, abscess, cancer, and tuberculous or fungal epididymitis (especially in immunocompromised patients) 1

Complications if Untreated

• Infertility can result from untreated acute epididymitis 6
• Chronic scrotal pain is a potential long-term complication 5, 6
• Post-inflammatory subfertility develops in approximately 40% of patients 4
• Abscess formation and testicular infarction are potential acute complications 1
• Approximately 88% of epididymal abscesses can be successfully treated without surgery 4