Epididymo-Orchitis: Evaluation, Red Flags & Management
Clinical evaluation of epididymo-orchitis in general practice: excluding testicular torsion red flags, age-specific pathogens, and antibiotic regimens.
Pathophysiology & Age-Based Etiology
Epididymo-orchitis is acute inflammation and infection of the epididymis and adjacent testis, typically caused by retrograde ascent of infectious pathogens along the vas deferens from the urethra or bladder. The causative micro-organisms divide into two distinct demographic cohorts:
- Sexually Active Men Under 35 Years: Predominantly caused by sexually transmitted pathogens: Chlamydia trachomatis and Neisseria gonorrhoeae.
- Men Over 35 Years or Following Urological Instrumentation: Predominantly caused by enteric Gram-negative urinary tract pathogens: Escherichia coli, Klebsiella, Proteus, or Pseudomonas, frequently secondary to bladder outflow obstruction (benign prostatic hyperplasia), catheterisation, or urethral strictures.
Clinical Assessment & Bedside Signs
Patients typically present with subacute, progressive unilateral scrotal pain and swelling developing over several days, accompanied by dysuria, urethral discharge, or fever.
- Cremasteric Reflex: Usually intact in epididymitis (elicited by lightly stroking the inner thigh, resulting in normal ipsilateral testicular elevation), whereas it is characteristically absent in testicular torsion.
- Prehn's Sign: Elevation of the affected hemiscrotum may relieve pain in epididymitis, but does not reliably relieve pain in torsion (and should not be relied upon in isolation).
- Diagnostic Workup: First-pass urine for chlamydia/gonorrhoea NAAT; midstream urine for microscopy and culture; urethral swab if discharge is visible; scrotal colour Doppler ultrasound to assess parenchymal blood flow.
Empirical Antimicrobial Regimens
Empirical antibiotic therapy is commenced immediately while awaiting microbiology results:
- Sexually Transmitted Pathogens Suspected (Age < 35 or STI risk): Ceftriaxone 500 mg IM stat (covers N. gonorrhoeae) PLUS Doxycycline 100 mg orally twice daily for 14 days (covers C. trachomatis).
- Enteric Urinary Pathogens Suspected (Age > 35 or low STI risk): High-dose oral Ciprofloxacin or Ofloxacin for 10 to 14 days (or trimethoprim-sulfamethoxazole based on regional sensitivities).
- Supportive Measures: Strict bed rest, scrotal elevation and supportive underwear, simple analgesia (paracetamol and NSAIDs like ibuprofen), and ice pack application.
- Follow-Up: Formal clinical review at 48 to 72 hours to ensure symptom improvement; lack of improvement warrants repeat ultrasound to exclude testicular abscess or infarction.
Archival Document Available: You can also access Dr Tseng's original reference sheet as a printable PDF.
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