What is epididymoorchitis?

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Epididymoorchitis: Definition, Diagnosis, and Management

Epididymoorchitis is an inflammatory condition affecting both the epididymis and testis, typically caused by infectious agents that reach these structures through retrograde propagation via the vas deferens or hematogenous spread. 1

Etiology and Epidemiology

The causative organisms vary by age group:

  • Men <35 years: Most commonly caused by sexually transmitted infections (STIs)

    • Chlamydia trachomatis
    • Neisseria gonorrhoeae 2, 1
  • Men >35 years: More commonly caused by enteric organisms associated with urinary tract infections

    • Escherichia coli and other gram-negative enteric bacteria
    • Often related to urinary tract abnormalities, recent instrumentation, or surgery 2, 1
  • Special cases:

    • Viral causes (particularly orchitis): Mumps virus, Coxsackie virus, rubella virus, Epstein-Barr virus, and varicella zoster virus 2
    • Fungal and mycobacterial causes: More common in immunosuppressed patients, including those with HIV 2

Clinical Presentation

  • Unilateral testicular pain and tenderness with gradual onset
  • Palpable swelling of the epididymis
  • Hydrocele may be present
  • Often accompanied by urethritis (which may be asymptomatic)
  • Fever and systemic symptoms may occur in severe cases 2, 1

Diagnostic Approach

  1. Physical examination:

    • Assess for unilateral testicular pain, tenderness, and swelling
    • Check for presence of hydrocele
    • Evaluate for Prehn sign (pain relief with testicular elevation) 1
  2. Laboratory testing:

    • Gram-stained smear of urethral exudate (>5 PMNs per oil immersion field indicates urethritis)
    • Culture or nucleic acid amplification test (NAAT) for N. gonorrhoeae and C. trachomatis
    • Urinalysis and urine culture
    • Syphilis serology and HIV testing 2, 1
  3. Imaging:

    • Doppler ultrasound of the scrotum is the standard imaging modality
    • Helps distinguish inflammatory conditions from testicular torsion
    • Shows increased blood flow in epididymoorchitis (versus decreased/absent flow in torsion) 1

Differential Diagnosis

Critical to distinguish from testicular torsion, which is a surgical emergency:

Feature Epididymoorchitis Testicular Torsion
Onset Gradual Sudden
Pain relief with elevation Yes (Prehn sign) No
Cremasteric reflex Present Absent
Testicular position Normal High-riding
Doppler ultrasound Increased blood flow Decreased/absent blood flow

Other conditions to consider: testicular tumor, abscess, infarction, and tuberculous or fungal epididymitis 2

Treatment

For men <35 years (likely STI-related):

  • Ceftriaxone 250 mg IM in a single dose
  • PLUS Doxycycline 100 mg orally twice a day for 10 days 2, 1

For men >35 years (likely enteric organisms):

  • Ofloxacin 300 mg orally twice a day for 10 days
  • OR Levofloxacin 500 mg orally once daily for 10 days 2, 1

Supportive measures:

  • Bed rest
  • Scrotal elevation
  • Analgesics until fever and local inflammation subside 2

Hospitalization considerations:

  • Severe pain suggesting alternative diagnoses
  • Febrile patients
  • Concerns about medication non-compliance 2, 1

Follow-Up and Complications

  • Clinical improvement should occur within 3 days of starting treatment

  • Failure to improve requires reevaluation of diagnosis and therapy

  • Persistent swelling or tenderness after completing antibiotics warrants comprehensive evaluation for other conditions 2, 1

  • Potential complications include:

    • Abscess formation
    • Testicular ischemia
    • Infertility
    • Chronic scrotal pain 1, 3

Management of Sexual Partners

  • For STI-related epididymoorchitis, sexual partners should be referred for evaluation and treatment if contact occurred within 60 days preceding symptom onset
  • Patients should avoid sexual intercourse until they and their partners complete treatment and are symptom-free 2, 1

Special Considerations

  • HIV-infected patients: Should receive the same treatment regimen as HIV-negative patients, but be aware that fungal and mycobacterial causes are more common 2, 1
  • Antibiotic resistance: Rising resistance to fluoroquinolones in E. coli isolates may necessitate alternative antimicrobials with adequate penetration into genital tissues 4
  • Surgical intervention: May be necessary if no clinical improvement is observed within 48-72 hours of conservative treatment, particularly in cases with hydrocele, abscess formation, or inability to differentiate between epididymis and testis on examination 3

References

Guideline

Scrotal Pain and Epididymoorchitis Management

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Acute epididymo-orchitis: staging and treatment.

Central European journal of urology, 2012

Research

Epididymo-orchitis caused by enteric organisms in men > 35 years old: beyond fluoroquinolones.

European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology, 2018

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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