How do I evaluate and treat acute orchitis in a male patient, including when to obtain an urgent scrotal ultrasound to exclude testicular torsion and which antibiotics to use based on age, suspected pathogen, and β‑lactam allergy?

Orchitis Treatment

Immediate Evaluation: Exclude Testicular Torsion First

Any acute scrotal pain must be treated as a potential surgical emergency until testicular torsion is excluded, regardless of the suspected diagnosis. 1

When to Obtain Urgent Scrotal Ultrasound

• Obtain immediate Duplex Doppler ultrasound if the patient presents with sudden onset of severe scrotal pain, especially if urinalysis does not support urethritis or UTI 1
• Proceed directly to surgical exploration without imaging if clinical suspicion for torsion is high (high-riding testicle, absent cremasteric reflex, severe acute unilateral pain with nausea/vomiting), as imaging should never delay surgery 1, 2
• Ultrasound has 69-96.8% sensitivity for torsion, meaning false-negatives occur in up to 30% of cases—clinical judgment supersedes imaging 1, 3

Key Clinical Distinguishing Features

• Testicular torsion: Abrupt onset, severe pain, negative Prehn sign (no relief with elevation), normal urinalysis 1
• Epididymo-orchitis: Gradual onset, may have abnormal urinalysis (though normal UA does not exclude it), positive Prehn sign 1, 4
• Age matters: Torsion peaks in neonates and postpubertal boys; epididymo-orchitis is most common in adults but can occur at any age 1, 5

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Antibiotic Treatment for Confirmed Epididymo-Orchitis

Age-Based Pathogen Considerations

Men < 35 years old (Sexually Transmitted Pathogens)

• Primary pathogens: Chlamydia trachomatis and Neisseria gonorrhoeae 4, 5
• First-line treatment: Doxycycline 100 mg PO twice daily for at least 10 days 6
  • For acute epididymo-orchitis caused by C. trachomatis: 100 mg PO BID × 10 days minimum 6
  • For acute epididymo-orchitis caused by N. gonorrhoeae: 100 mg PO BID × 10 days minimum 6
• If β-lactam allergy: Doxycycline is already the preferred agent and does not contain β-lactam 6

Men ≥ 35 years old (Enteric Organisms)

• Primary pathogen: E. coli and other enteric bacteria, often associated with bladder outlet obstruction (BPH, urethral stricture) 7, 4
• Traditional treatment: Fluoroquinolones (ciprofloxacin) have been the mainstay, but rising resistance in E. coli necessitates alternative antimicrobials with adequate genital tissue penetration 7
• If β-lactam allergy: Fluoroquinolones remain an option; however, consider local resistance patterns and alternative agents with good epididymal penetration 7

Supportive Measures

• Bed rest, scrotal elevation, and analgesics until inflammation subsides 1, 5
• Patients in severe pain or systemically unwell require referral for IV antibiotics, analgesia, and hydration 4

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Critical Pitfalls to Avoid

• Never delay surgical exploration for imaging when torsion is clinically suspected—testicular viability is compromised after 6-8 hours 1, 2
• Normal Doppler ultrasound does not exclude torsion, especially with partial or intermittent torsion 1, 3
• Failure to improve within 3 days of appropriate antibiotics warrants urgent urological consultation to exclude testicular malignancy, complicated infection, or missed torsion 3
• Examine for bladder outlet obstruction (palpable bladder, BPH on DRE) in men ≥35 with epididymo-orchitis, as enteric organisms are often associated with functional urinary problems 4
• Consider testicular malignancy if persistent tenderness, swelling, or palpable mass after failed antibiotic treatment—obtain serum tumor markers immediately 3

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Algorithm Summary

1. Acute scrotal pain → Assess for torsion clinically (sudden onset, severe pain, high-riding testis, absent cremasteric reflex)
2. High suspicion for torsion → Immediate urological consultation and surgical exploration (do not wait for imaging) 1, 2
3. Intermediate suspicion → Urgent Duplex Doppler ultrasound with grayscale, color Doppler, and power Doppler 1
4. Torsion confirmed or highly suspected → Surgery within 6-8 hours 1, 2
5. Epididymo-orchitis confirmed → Age-based antibiotic selection:
   • < 35 years: Doxycycline 100 mg PO BID × 10 days minimum 6
   • ≥ 35 years: Fluoroquinolone (consider local resistance) or alternative with good tissue penetration 7
6. No improvement in 3 days → Urgent urology referral to exclude malignancy or complicated infection 3