🌸 Epididymitis Antibiotic Treatment Simulator
The simulator differentiates between bacterial (chlamydial/gonococcal) etiology of epididymitis, presents the Prehn's sign, and selects an appropriate antibiotic treatment regimen.
Scrotal Pain & Swelling
Gradual, unilateral scrotal pain over days signals epididymitis, not torsion.
- Gradual: Onset speed (hours to days)
- Sudden: Torsion onset (minutes, for contrast)
- 14–35: Typical age (sexually active men)
- 600k/yr: Peak incidence (US outpatient visits)
Gradual onset is the key clue
Pain builds slowly, often with fever and dysuria.
Posterior tenderness
Swelling starts at the epididymis, behind the testicle.
Why timing matters
Torsion is a surgical emergency; epididymitis is not.
Prehn's Sign Assessment
Lifting the scrotum eases pain in epididymitis, not in torsion.
- Positive: Prehn's sign (relief with elevation)
- Negative: Torsion Prehn (no relief, or worse)
- Intact: Cremasteric reflex (usually present)
- Limited: Exam reliability (ultrasound still needed)
The maneuver
Gently raise the scrotum and ask about pain change.
Relief supports infection
Elevation reduces venous congestion, easing inflamed tissue.
Not definitive alone
Doppler ultrasound confirms blood flow either way.
Etiology Differentiation
Age and sexual history split epididymitis into STI or enteric causes.
- STI likely: Under 35 (chlamydia, gonorrhea)
- Enteric likely: Over 35 (E. coli, coliforms)
- Enteric risk: Anal intercourse (any age)
- Pyuria: Urinalysis (supports diagnosis)
Sexually transmitted cause
Chlamydia trachomatis and Neisseria gonorrhoeae dominate under 35.
Enteric cause
E. coli follows urinary reflux, common in older men.
Testing
NAAT for STIs plus urine culture guide therapy.
Antibiotic Regimen Selection
The chosen regimen must match the suspected pathogen exactly.
- CRO+Doxy: STI regimen (ceftriaxone + doxycycline)
- Fluoroquinolone: Enteric regimen (levofloxacin or ofloxacin)
- 500 mg IM: Ceftriaxone dose (single dose)
- 10 days: Doxycycline course (oral, twice daily)
STI-suspected regimen
Ceftriaxone injection plus ten days of doxycycline.
Enteric-suspected regimen
A fluoroquinolone covers E. coli and coliforms.
Partner treatment
STI cases require partner notification and treatment.
Symptom Resolution
Swelling and pain fade over days as antibiotics clear infection.
- 2–3 days: Symptom relief (pain begins easing)
- ~2 weeks: Swelling resolves (full course needed)
- Low: Recurrence risk (if course completed)
- 72 hours: Follow-up (confirm improvement)
Completing the course
Full antibiotic duration prevents relapse and abscess.
Supportive care
Scrotal support and rest speed comfort during healing.
When to escalate
No improvement in 72 hours warrants imaging.
The simulator differentiates between bacterial (chlamydial/gonococcal) etiology of epididymitis, presents the Prehn's sign, and selects an appropriate antibiotic treatment regimen.
2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install