Epididymo-orchitis
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Direct answer
Gradual-onset scrotal pain with fever over two or three days, tenderness that starts at the lower pole of the epididymis behind the testis, and dysuria with pyuria — that constellation is epididymo-orchitis, and the patient's age names the organism. Under thirty-five, Chlamydia trachomatis and gonorrhoea, sexually transmitted; over thirty-five or after instrumentation, coliforms from the urinary tract. Treatment is ceftriaxone plus doxycycline for the young man and a fluoroquinolone for the older, with scrotal support and rest. The diagnosis that must never be missed is torsion — Doppler ultrasound whenever doubt exists, because the Prehn sign (relief of pain on elevating the scrotum) is too unreliable to gamble a testicle on. In Indian practice, chronic painless epididymal induration with a beaded vas argues for tuberculosis.
What you must remember
- Age-pathogen rule: under 35 — chlamydia and gonococcus: ceftriaxone 250 mg intramuscularly as a single dose plus doxycycline 100 mg twice daily for 10-14 days, with partner treatment; over 35 or insertive MSM — Enterobacteriaceae, often with benign prostatic obstruction or catheters: a fluoroquinolone for 10-14 days, guided by culture.
- Bedside picture: fever, exquisitely tender posterolateral scrotal swelling beginning at the epididymal lower pole, reactive hydrocele, pyuria on urinalysis; the cremasteric reflex is usually preserved (typically absent in torsion).
- Investigations: urinalysis and culture, first-void nucleic-acid amplification test for chlamydia and gonorrhoea in the young; Doppler ultrasound when torsion is possible or an abscess is suspected.
- Torsion safeguard: sudden onset, age 12-18, a high-lying transverse testis, absent cremasteric reflex and vomiting — explore or scan within the hour; a lost hour after six is a lost testis.
- Complications: abscess and pyocele, testicular infarction, chronic epididymal pain, and infertility when bilateral obstruction or testicular damage develops.
- Mumps orchitis: a postpubertal complication of mumps — parotitis preceding a painful swollen testis, testicular atrophy risk, and impaired fertility when bilateral; supportive treatment only.
- Tuberculous epididymitis (Indian classic): chronic, nearly painless, hard epididymal enlargement, beaded vas deferens, cold scrotal abscess or sinus, sterile pyuria — antitubercular therapy, not repeated courses of ordinary antibiotics.
The acute scrotum, sorted
Four diseases produce an acutely painful scrotum, and the sorting is clinical before it is radiological. Torsion: a teenager with sudden severe pain, vomiting, a high-riding transverse testis, absent cremasteric reflex — the surgical emergency, where Doppler must not delay theatre. Epididymo-orchitis: a young adult with days of worsening pain, fever, dysuria and pyuria, tenderness greatest behind the testis — antibiotics, rest, scrotal support. Strangulated inguinoscrotal hernia: an irreducible groin lump with obstructive signs — surgical. Testicular tumour: usually painless, but haemorrhage into a tumour can mimic acute orchitis — hence the rule that every "orchitis" that does not settle deserves an ultrasound, because a tumour hiding behind inflammation is the trap.
The pathway then is discipline: if the history and signs fit infection and torsion is unlikely, treat and review at 48 hours. Improvement confirms; no improvement demands ultrasound for abscess, pyocele or tumour. The man over 50 with coliform epididymitis needs his prostate and bladder assessed once the inflammation settles — the infection is a symptom of the outflow, not the whole disease.
The Prehn sign trap
The Prehn sign — pain relieved by elevating the scrotum, suggesting epididymitis and worsening in torsion — appears in older textbooks as a discriminator and fails often enough that no modern guideline trusts it; NBE has caught up, and the keyed answer to "next step in suspected torsion" is colour Doppler or exploration, never a sign. The second tested pair is age-pathogen with its two regimens, asked as a pharmacology MCQ in surgical clothing. The Indian tier adds tuberculosis: the beaded vas and cold abscess are quotable examination findings, and the discipline is sending urine for mycobacteria and starting antitubercular therapy rather than a fourth fluoroquinolone course.
Frequently asked questions
Which pathogens and treatment for epididymitis under 35?
Chlamydia trachomatis and Neisseria gonorrhoeae — ceftriaxone 250 mg intramuscularly once plus doxycycline 100 mg twice daily for 10-14 days, with partner treatment.
Is the Prehn sign reliable for excluding torsion?
No — it is too insensitive to trust; colour Doppler ultrasound or exploration is required whenever torsion is possible.
What are the consequences of mumps orchitis?
Testicular pain and swelling after parotitis in a postpubertal man, with risk of testicular atrophy and impaired fertility when both sides are involved.
Which features suggest tuberculous epididymitis?
Chronic painless hard epididymis, beaded vas deferens, cold abscess or scrotal sinus, and sterile pyuria — treated with antitubercular therapy.
When should an apparent epididymitis be imaged?
Failure to improve within 48 hours of appropriate antibiotics, or a palpable mass — ultrasound excludes abscess, pyocele and tumour masquerading as infection.