Epididymitis

Basics

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)

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