Epididymitis Explained: Diagnosis, Causes, and Treatment by Age and Risk Factors

🔹 Definition

Epididymitis is the inflammation of the epididymis, the coiled duct located posterior to the testis responsible for sperm transport and maturation. It is a common cause of acute scrotal pain in adults, often resulting from bacterial infection ascending from the urethra, prostate, or bladder. When the inflammation extends to the testis, the condition is called epididymo-orchitis.

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🔹 Etiology

1. Infectious Causes

• Sexually transmitted infections (STIs) — common in sexually active men <35 years:

  • Chlamydia trachomatis

  • Neisseria gonorrhoeae

• Urinary tract pathogens — common in older men (>35 years) or those with bladder outlet obstruction or instrumentation:

  • Escherichia coli

  • Pseudomonas aeruginosa

• Insertive anal intercourse: may involve coliforms + STI organisms.

2. Non-infectious Causes

• Trauma

• Drug-induced (e.g., amiodarone)

• Autoimmune disorders

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🔹 Pathophysiology

Infectious organisms ascend via the vas deferens from the urethra or bladder → invade the epididymal duct → trigger an inflammatory response → resulting in pain, swelling, and hyperemia.If untreated, it may extend to the testis (epididymo-orchitis) or form abscesses.

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🔹 Diagnostic Criteria

Diagnosis is clinical, supported by ultrasound and laboratory findings.

Typical Diagnostic Features

• Gradual onset of unilateral scrotal pain and swelling (hours–days).

• Tenderness and induration localized to the posterior aspect of the testis (epididymis).

• Prehn’s sign positive — elevation of scrotum relieves pain.

• Cremasteric reflex preserved (absent in torsion).

• May have dysuria, frequency, or urethral discharge (STI-related).

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🔹 Investigations

1. Scrotal Ultrasound with Color Doppler (Key Diagnostic Test)

• Findings:

  • Enlarged, hypoechoic epididymis.

  • Increased blood flow (hyperemia) to epididymis and testis.

  • Reactive hydrocele may be present.

  • Rule out torsion: Torsion shows absent or decreased blood flow.
    

2. Laboratory Tests

Test	Purpose / Findings
Urinalysis and Urine Culture	Detect pyuria or bacteriuria (UTI pathogens).
Urethral swab or NAAT (PCR)	Identify Chlamydia trachomatis and Neisseria gonorrhoeae.
CBC, CRP, ESR	Leukocytosis and elevated inflammatory markers.
HIV and Syphilis screening	If STI suspected.
Urine Gram stain	For antibiotic guidance.

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🔹 Management

Step 1: Determine Setting

• Outpatient (OPD): Most cases (mild–moderate, stable).

• Inpatient (IPD): Severe systemic illness, abscess formation, immunocompromised, or torsion not excluded.
  

Step 2: Definitive Treatment (Antibiotics)

1. STI-related Epididymitis (<35 years old):

• Ceftriaxone 500 mg IM single dose+ Doxycycline 100 mg PO bid × 10 days

2. Non-STI/UTI-related Epididymitis (>35 years old, instrumentation, obstruction):

• Levofloxacin 500 mg PO daily × 10 daysOR

• Ofloxacin 300 mg PO bid × 10 days

3. Insertive Anal Intercourse (mixed pathogens):

• Ceftriaxone 500 mg IM single dose+ Levofloxacin 500 mg PO daily × 10 days
  

Step 3: Supportive Treatment

• Analgesia / NSAIDs: e.g., Ibuprofen 400 mg PO every 8 hours.

• Scrotal elevation and support: improves venous return and reduces pain.

• Bed rest: until inflammation subsides.

• Adequate hydration.
  

Step 4: Partner Management

• Treat and test all sexual partners within the past 60 days for Chlamydia and Gonorrhea.

• Abstain from sexual activity until both patient and partner complete therapy and are asymptomatic.
  

Step 5: Follow-up and Monitoring

• Re-evaluate in 3–7 days:

  • If symptoms worsen or fail to improve → reassess diagnosis (possible torsion, abscess, tumor).

• Monitor for complications:

  • Abscess formation

  • Chronic epididymitis

  • Testicular infarction

  • Infertility (rare)
    

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🔹 Prognosis

• Excellent with prompt antibiotic therapy.

• Most patients recover fully within 2–4 weeks.

• Delay in diagnosis or inadequate treatment may lead to chronic pain or infertility.

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🔹 Summary Table

Aspect	Epididymitis
Onset	Gradual (hours–days)
Pain Location	Posterior scrotum
Prehn’s sign	Positive
Cremasteric reflex	Present
Ultrasound	Increased blood flow (hyperemia)
Treatment	Antibiotics + Supportive
Common Pathogens	Chlamydia, Gonorrhea (<35 yrs); E. coli (>35 yrs)

Key Clinical Pearl:

Always exclude testicular torsion in acute scrotal pain — torsion is sudden, severe, with absent Doppler flow and requires emergency surgery.