Description

Epididymitis is an acute inflammation of the epididymis which can cause severe scrotal pain. It is important to differentiate epididymitis from testicular torsion or testicular appendage torsion.

Epidemiology

• Epididymitis is the most common cause of acute scrotum, approximately 37–65% of cases. The incidence ranges between 0.8 and 1.2 cases per 1,000 persons per year.
• There is a bimodal distribution with a peak in incidence in infants <1 year of age and peripubertal boys.

Risk Factors

Urologic manipulation (cystoscopy, intermittent self-catheterization, surgery of the urethra)

Pathophysiology

• The majority of epididymitis is idiopathic (73%).
• Viral epididymitis: second most common cause
  • Urinalysis and culture are negative.
  • Often elevated titers of enterovirus, Mycoplasma pneumoniae, and adenoviruses.
  • New research suggests that some epididymitis might be due to postinfectious inflammation as 50% of patients had respiratory symptoms within 1 month of presentation, and presentations appear to peak in concert with rotavirus and enterovirus.
• Bacterial epididymitis: 2–6% of cases and is related to age
  • Due to ascending infection from the urethra or bladder, reflux of infected urine into the vas deferens, or hematogenous dissemination
  • Infants <1 year:
    • Typically due to genitourinary anomalies (73% vs. 21% in children >1)
    • Abnormalities include meatal stenosis, neurogenic voiding dysfunction, urethral stenosis, posterior urethral valves, ectopic ureter.
    • Typical bacteria include Escherichia coli, Klebsiella, and Enterococcus.
    • Postpubertal sexually active boys may have infection with sexually transmitted diseases such as gonorrhea or chlamydia.
• Chemical epididymitis: due to reflux of sterile urine into the vas deferens or drugs (amiodarone)
• Posttraumatic

Commonly Associated Conditions

• Systemic serositis (familial Mediterranean fever, sarcoidosis, Kawasaki disease)
• Systemic vasculitis (Henoch-Schönlein purpura, polyarteritis nodosa)