Reproductive · Infectious Disease
The facts most likely to be tested
Prehn sign is a classic clinical finding where scrotal elevation provides pain relief in epididymitis, helping to distinguish it from testicular torsion.
Chlamydia trachomatis and Neisseria gonorrhoeae are the most common pathogens in men younger than 35 years old.
Enterobacteriaceae (e.g., E. coli) are the most common pathogens in men older than 35 years old or those with bladder outlet obstruction.
Doppler ultrasound is the diagnostic test of choice to confirm increased blood flow to the epididymis and rule out testicular torsion.
Ceftriaxone plus Doxycycline is the empiric treatment regimen for patients at risk for sexually transmitted infections.
Levofloxacin or Ofloxacin is the preferred empiric treatment for patients at low risk for sexually transmitted infections.
Cremasteric reflex remains intact in epididymitis, whereas it is typically absent in cases of testicular torsion.
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A 28-year-old male presents to the urgent care clinic with a 3-day history of gradual onset left-sided scrotal pain and swelling. He reports associated dysuria and frequency. On physical exam, the left hemiscrotum is tender and indurated at the posterior aspect. Scrotal elevation results in significant pain relief. The cremasteric reflex is present bilaterally.
What is the most likely diagnosis and the most appropriate empiric antibiotic therapy?
Epididymitis; Ceftriaxone and Doxycycline.
The patient's presentation of gradual pain, positive Prehn sign, and intact cremasteric reflex points to epididymitis, and his age group necessitates coverage for common STIs.
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High yield triage
Etiology / Epidemiology
Age <35: Chlamydia trachomatis or Neisseria gonorrhoeae. Age >35: E. coli (enteric organisms).
Clinical Manifestations
Gradual onset unilateral scrotal pain and swelling. Prehn sign: relief with scrotal elevation.
Diagnosis
Scrotal ultrasound with Doppler is the gold standard to rule out torsion.
Treatment
Age <35: Ceftriaxone + Doxycycline. Age >35: Levofloxacin. Avoid fluoroquinolones in pregnancy.
Prognosis
Most resolve with antibiotics; infertility is a rare but serious long-term complication.
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Epidemiology & Etiology
In men <35, it is primarily a sexually transmitted infection. In men >35, it is typically associated with bladder outlet obstruction or BPH leading to retrograde flow of infected urine. Rare cases are caused by Amiodarone toxicity.
Pertinent Anatomy
The epididymis is a coiled tube located on the posterior aspect of the testis. Inflammation here causes localized tenderness distinct from the testis itself.
Pathophysiology
Infection typically spreads via the vas deferens from the urethra or bladder. The resulting inflammatory response causes edema, which can lead to testicular ischemia if the pressure is high enough to compress the testicular artery.
Clinical Manifestations
Patients present with unilateral scrotal pain, swelling, and tenderness. Prehn sign (relief with elevation) is classic but not diagnostic. Red flags include high fever, severe systemic toxicity, or abscess formation requiring surgical drainage.
Diagnosis
Scrotal ultrasound is the gold standard to differentiate from torsion; it shows increased blood flow (hyperemia) and enlarged epididymis. Urinalysis and NAAT for gonorrhea/chlamydia are mandatory for etiology.
Treatment
For <35: Ceftriaxone 500mg IM once plus Doxycycline 100mg BID for 10 days. For >35: Levofloxacin 500mg daily for 10 days. Fluoroquinolones are contraindicated in pregnancy and carry a risk of tendon rupture.
Prognosis
Most patients improve within 48-72 hours of therapy. Chronic pain or infertility due to scarring are the primary long-term concerns.
Differential Diagnosis
Testicular Torsion: absent cremasteric reflex and decreased flow on Doppler
Orchitis: testicular swelling often associated with mumps
Inguinal Hernia: bowel sounds in the scrotum
Hydrocele: painless, transilluminates on exam
Spermatocele: painless, cystic mass at the epididymal head