Epididymitis

DESCRIPTION

Epididymitis is an acute inflammation of the epididymis that can cause severe scrotal pain. It is important to differentiate epididymitis from testicular torsion (TT) 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)
• Viral illness
• Sexually transmitted infections
• Anatomic congenital and acquired urologic abnormalities (e.g., ectopic ureter; posterior urethral valves, urethral abnormalities)

PATHOPHYSIOLOGY

• The majority of cases of epididymitis are idiopathic (73%).
• Viral epididymitis: second most common cause
  • Urinalysis and culture are negative.
  • Often elevated titers of enterovirus, Mycoplasma pneumoniae, and adenoviruses
  • Some cases of epididymitis may 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 aged <1 year:
    • Typically, due to genitourinary anomalies (73% vs. 21% in children aged >1 year)
    • Abnormalities include meatal stenosis, neurogenic voiding dysfunction, urethral stenosis, posterior urethral valves, and ectopic ureter.
    • Typical bacteria include Escherichia coli, Klebsiella, and Enterococcus.
  • Postpubertal sexually active and sexually abused patients may have acquired sexually transmitted infections such as gonorrhea or chlamydia.
• Chemical epididymitis: due to reflux of sterile urine into the vas deferens or drugs (amiodarone)
• Posttraumatic
• Torsion of an epididymal appendage

COMMONLY ASSOCIATED CONDITIONS

• Systemic serositis (familial Mediterranean fever, sarcoidosis, Kawasaki disease)
• Systemic vasculitis (Henoch-Schönlein purpura, polyarteritis nodosa)
• Voiding dysfunction
• Urethral strictures distal to the external sphincter