Epidemiology
Etiology
- Age < 35 y/o: Sexually transmitted infections (STI).
- Chlamydia trachomatis (most common overall), Neisseria gonorrhoeae.
- Risk factors: Multiple sexual partners, unprotected intercourse.
- Age ≥ 35 y/o: Enteric uropathogens.
- Escherichia coli (most common), Pseudomonas spp.
- Risk factors: BPH, bladder outlet obstruction, recent GU instrumentation/Foley catheterization.
- Children: Congenital GU anomalies (e.g., ectopic ureter, posterior urethral valves), viral (enterovirus).
- Non-infectious: Chronic Amiodarone therapy (dose-dependent sterile inflammation).
Pathophysiology
Clinical features
- Unilateral scrotal pain and swelling, which develops over several days and radiates to the ipsilateral flank
- Tenderness along the posterior testis
- Positive Prehn sign: reduced pain when the affected hemiscrotum is elevated
- Scrotal skin overlying the epididymis may appear red, shiny, and edematous
- Low-grade fever (especially among children)
- Symptoms of lower urinary tract infection (e.g., dysuria, frequency, urgency), including urethritis (urethral discharge)
Tip
- Testicular torsion: negative Prehn sign, negative cremasteric reflex
- Epididymitis: positive Prehn sign, positive cremasteric reflex