Epididymitis

Epididymitis is inflammation of the epididymis, and epididymo-orchitis involves the adjacent testis (in 20 to 40%). It is a common cause of acute scrotal pain in adult men, with about 600,000 cases yearly in the United States. It may be acute (symptoms under 6 weeks), subacute (6 weeks to 3 months), or chronic (over 3 months of pain, with or without inflammation).

Aetiology depends on age and sexual practices

• Men under 35 (sexually active): sexually transmitted organisms: Chlamydia trachomatis (the commonest), Neisseria gonorrhoeae, Mycoplasma genitalium, and Ureaplasma. Also Trichomonas.
• Men over 35 and those who practise insertive anal sex: enteric Gram-negative bacilli (E. coli, Klebsiella, Pseudomonas, Proteus) via reflux of infected urine into the vas deferens, associated with bladder outlet obstruction, benign prostatic hyperplasia, urethral stricture, urinary tract infection, catheterisation, or recent urological instrumentation (cystoscopy, prostate biopsy, catheter). MSM may have both.
• Children and boys: usually post-viral or idiopathic, or associated with congenital urinary tract anomalies (ectopic ureter, posterior urethral valves, vesicoureteral reflux), enteric organisms, and rarely sexual abuse. Torsion must be excluded.
• Other causes: viral (mumps, coxsackievirus, adenovirus), mycobacterial (tuberculosis, BCG after intravesical therapy), fungal (Candida, Cryptococcus, Coccidioides), Brucella (endemic regions), Salmonella, schistosomiasis, amiodarone-induced (non-infectious, in the epididymal head), sarcoidosis, Behçet disease, vasculitis (Henoch-Schönlein purpura), vasectomy (congestive epididymitis), and trauma or heavy lifting (reflux of sterile urine, chemical epididymitis).

Complications

• Abscess formation and testicular infarction, pyocele, chronic epididymitis or orchialgia, scarring with obstruction and infertility (especially bilateral), epididymal-cutaneous fistula, and sepsis. Spread of infection to the testis (orchitis) may lead to atrophy.
• Risk factors: unprotected sex, new partners, previous STI, urinary tract obstruction, BPH, catheterisation, urological instrumentation, diabetes, immunosuppression, anatomical abnormality, and strenuous activity.

Acute epididymitis

• Gradual onset (over hours to days) of unilateral scrotal pain, posterior to the testis, radiating to the groin, flank or lower abdomen, with scrotal swelling, erythema and warmth, hydrocele, and fever or chills.
• Associated lower urinary tract symptoms (dysuria, frequency, urgency) or urethral discharge, or both, in STI-related cases.
• Examination: tender, swollen epididymis (initially the tail, then entire), possibly with a thickened spermatic cord and tender vas, enlargement of the testis in orchitis, scrotal skin erythema and oedema, and reactive hydrocele. A positive Prehn sign (pain relief on testicular elevation) is suggestive but unreliable. The cremasteric reflex is typically preserved.
• Urethral discharge, tender prostate (prostatitis), and inguinal lymphadenopathy may be present.

Chronic epididymitis

• Scrotal, groin or testicular pain lasting more than 3 months, often dull and aching, with epididymal induration or tenderness on examination. Some patients have a normal examination.
• It follows unresolved acute infection, obstruction (vasectomy, scarring), amiodarone, or a chronic pain syndrome with pelvic floor involvement.

Differential diagnosis

• Testicular torsion: the key diagnosis not to miss. Peaks at 12 to 18 years but occurs at any age. Sudden onset, high-riding horizontal testis, absent cremasteric reflex, and no urinary symptoms or fever.
• Torsion of the testicular appendage (blue dot sign), testicular tumour, strangulated inguinal hernia, infected hydrocele or haematocele, trauma, and spermatocele.
• Referred pain from ureteric stone or lumbar root, Henoch-Schönlein purpura in children, and Fournier gangrene.

Red flags

• Sudden severe pain in a young male (treat as torsion until excluded).
• Fever with hypotension, crepitus, skin necrosis or rapidly spreading erythema (necrotising infection).
• Fluctuant swelling (abscess), urinary retention, and failure to improve within 72 hours.
• Hard testicular nodule, which suggests a tumour.

Exclude torsion first. Any suspicion in a patient under 20, or with sudden onset, needs urgent colour Doppler ultrasound or immediate surgical exploration without waiting for imaging. Exploration should occur within 6 hours of onset for best salvage.

Targeted tests

• Urethral Gram stain or smear: 2 or more polymorphonuclear leukocytes per oil immersion field, with intracellular Gram-negative diplococci in gonorrhoea.
• First-void urine NAAT (or urethral swab) for Chlamydia trachomatis, Neisseria gonorrhoeae and Mycoplasma genitalium.
• Urinalysis and midstream urine culture for enteric organisms. Pyuria and bacteriuria are common.
• CBC, CRP, creatinine, glucose or HbA1c, and blood cultures when febrile or septic.
• HIV and syphilis serology in all sexually active patients.
• Tuberculosis workup (three early-morning urine samples for AFB, interferon gamma release assay), Brucella serology, and fungal cultures in persistent or granulomatous disease.

Scrotal colour Doppler ultrasound

• Enlarged, heterogeneous, hypoechoic or hyperaemic epididymis with increased flow, thickened spermatic cord, reactive hydrocele, and scrotal wall thickening. Epididymal flow is increased, and testicular flow is preserved or increased in orchitis.
• Reduced or absent testicular flow indicates torsion or infarction from venous compression in severe epididymo-orchitis.
• Look for abscess, pyocele, and a testicular mass.

Additional evaluation

• Men over 35 or with recurrent episodes: post-void residual by bladder scan, uroflowmetry, renal tract ultrasound, and cystoscopy or urethrography for obstruction or stricture.
• Persistent swelling beyond 4 to 6 weeks: repeat ultrasound and tumour markers (AFP, beta hCG, LDH) to exclude malignancy.
• Chronic pain: semen analysis, and review of medications (amiodarone).

Start empirical therapy as soon as samples are taken, and tailor to age and risk.

Sexually transmitted infection likely (men under 35, or high-risk exposure)

• Ceftriaxone 500 mg IM single dose plus doxycycline 100 mg orally twice daily for 10 to 14 days.
• Gonorrhoea or chlamydia with insertive anal sex: add enteric cover with levofloxacin 500 mg daily or ofloxacin 300 mg twice daily for 10 days.
• Mycoplasma genitalium: doxycycline 100 mg twice daily for 7 days, then moxifloxacin 400 mg daily for 7 to 10 days if macrolide-resistant (or azithromycin 1 g then 500 mg daily for 3 days if susceptible).

Enteric organisms likely (men over 35, urinary tract disease, instrumentation)

• Levofloxacin 500 mg daily for 10 days, or ciprofloxacin 500 mg twice daily for 10 to 14 days.
• Alternatives: trimethoprim-sulfamethoxazole 160/800 mg twice daily for 10 to 14 days, or amoxicillin-clavulanate 875/125 mg twice daily.
• Fluoroquinolones carry risks (tendinopathy, QT prolongation, neuropsychiatric effects, aortic aneurysm), so choose according to local resistance and tolerability.

Severe or systemic illness (sepsis, vomiting, immunosuppression, abscess, diabetes with poor control)

• Admit. Give ceftriaxone 1 to 2 g IV daily, or piperacillin-tazobactam 4.5 g IV every 6 to 8 hours, with gentamicin 5 mg/kg IV daily when indicated. Use meropenem 1 g IV every 8 hours for ESBL risk.
• Switch to oral therapy after 24 to 48 hours of improvement, and complete 14 days (longer for abscess).

Supportive care

• Bed rest for the first days, scrotal elevation and support, cold packs for 15 to 20 minutes at a time, and hydration.
• Ibuprofen 400 to 600 mg every 8 hours or naproxen 500 mg twice daily with food. Paracetamol 1 g every 6 hours. Short opioid course for severe pain.
• Spermatic cord block with lidocaine 1% (10 to 20 mL) with or without bupivacaine for severe pain.
• Avoid sexual intercourse until treatment is complete and partners are treated.

Specific causes

• Amiodarone epididymitis: reduce the dose or stop if possible (resolves in weeks).
• Tuberculous epididymitis: standard four-drug anti-tuberculosis therapy for 6 months.
• Brucellosis: doxycycline 100 mg twice daily with rifampicin 600 to 900 mg daily for 6 weeks (or with streptomycin 1 g IM daily for 2 to 3 weeks).
• Viral (mumps, enteroviruses): supportive treatment only.
• Underlying obstruction (BPH, stricture): relieve with catheterisation, alpha blocker, or urological intervention.

Complications

• Abscess or pyocele: ultrasound-guided aspiration or surgical drainage. Epididymectomy or orchiectomy for non-viable tissue, chronic sinus, or failure of drainage.
• Testicular infarction: orchiectomy.
• Chronic epididymitis: trial of antibiotics for 4 to 6 weeks, NSAIDs, neuropathic agents (gabapentin 300 mg at night titrated to 1800 mg/day, amitriptyline 10 to 50 mg at night), cord block, pelvic floor physiotherapy, and epididymectomy or microsurgical denervation of the spermatic cord for refractory pain after careful counselling.

Partner management and follow-up

• STI-related: notify and treat partners from the preceding 60 days, abstain until both complete therapy plus 7 days, and retest for chlamydia and gonorrhoea at 3 months.
• Review at 72 hours. Failure to improve warrants repeat ultrasound for abscess, torsion, tumour, or tuberculosis.
• Review at 2 weeks and again at 4 to 6 weeks if swelling persists. Swelling may take weeks to months to resolve.
• Bilateral disease or recurrent episodes: semen analysis and fertility counselling, because obstruction can follow.