Epididymo-orchitis

Acute epididymitis is an inflammation of the epididymis. When infection is severe and extends to the adjacent testicle, it causes acute epididymo-orchitis. Chronic epididymitis refers to epididymal pain and inflammation (usually without scrotal swelling) that lasts for more than 6 months. Orchitis (infection limited to the testis) is much less common.¹

• In men younger than 35 years of age, epididymo-orchitis is most often caused by sexually transmitted pathogens such as Chlamydia trachomatis and Neisseria gonorrhoeae.²
• In men older than 35 years of age epididymo-orchitis is most often caused by non-sexually transmitted Gram negative enteric organisms causing urinary tract infections, e.g. E. coli, Pseudomonas spp.
• Gram-negative enteric organisms are more commonly the cause of epididymo-orchitis if recent instrumentation or catheterisation has occurred.
• Obstruction: adults older than 40 years usually have a bladder outlet obstruction, (e.g. benign prostatic hyperplasia or urethral stricture; children may have various congenital abnormalities or functional voiding problems.
• Men with Behcet's disease may develop a non-infective epididymo-orchitis.
• Epididymo-orchitis has also been reported as an adverse effect of amiodarone. This is a dose-dependent, and usually occurs at doses greater than 200 mg daily.
• Trauma to the scrotum can be a precipitating event.
• Other rare infections (e.g. brucellosis, coccidioidomycosis, blastomycosis, cytomegalovirus and candidiasis) usually occur in immunocompromised hosts.

Aetiology of acute orchitis

• Viral: mumps orchitis is most common. Coxsackievirus type A, varicella, and echoviral infections are rare.
• Bacterial and pyogenic infections: E. coli, Klebsiella, Pseudomonas, Staphylococcus, and Streptococcus species are unusual.
• Granulomatous: syphilis, tuberculosis, leprosy, Actinomyces, and fungal diseases are rare.
• Trauma.
• Idiopathic.

• The estimated incidence is 1 in 1,000 men.³
• Acute epididymitis most commonly occurs in patients aged 15-30 years and patients older than 60 years. Prepubertal epididymitis is rare (and testicular torsion is much more common in this age group).
• Structural urological abnormalities are common in children and in men older than 40 years with acute epididymitis. Adults usually have bladder outlet obstruction or urethral stricture; children may have an ectopic ureter, posterior urethral valves or vesicoureteral reflux.
• Mumps orchitis occurs in 20-40% of postpubertal boys with mumps; it is rare in prepubertal boys.

Risk factors

• Instrumentation and indwelling catheters are common risk factors for acute epididymitis. Urethritis or prostatitis may also coexist.
• Reflux of infected urine from the prostatic urethra to the epididymis via the ejaculatory ducts and vas deferens may be induced by Valsalva or strenuous exertion. Epididymitis is common in men performing strenuous exertion when there is no opportunity to void, resulting in a full bladder.

• Usually presents with swelling, scrotal erythema and pain.
• Acute epididymitis is usually unilateral but is bilateral in 5-10% of the patients.
• In sexually transmitted epididymo-orchitis there may be symptoms of a urethritis, e.g. urethral discharge.
• Mumps orchitis: fever, malaise, and myalgia. Parotiditis often precedes the onset of orchitis by 3-5 days. Subclinical infections occur in 30-40% of patients.
• Patient may be pyrexial.
• Tenderness on palpation.
• Palpable swelling of the epididymis.
• Erythema, oedema and mild scrotal cellulitis may be present.
• A reactive hydrocoele is frequent with advanced epididymo-orchitis, which may make scrotal examination difficult.

Careful evaluation for the possible causes of acute scrotal pain and swelling is essential.⁴

• Torsion:
  • More likely if the pain has a sudden onset and is severe
  • More common in men under 20 years (but can occur at any age)
  • Must be excluded as testicular torsion is a surgical emergency
• Trauma
• Abscess formation
• Testicular tumour
• Mumps epididymo-orchitis
• Tuberculous or fungal epididymitis
• Hydrocoele

• Urethral swab and first void urine: for gonorrhoeae and chlamydia infection.
• Screen for UTI: midstream urine for microscopy, culture and sensitivities.
• Screen for urethritis: all patients with sexually transmitted epididymo-orchitis should be screened for other sexually transmitted infections. Sexual contacts should also be evaluated.
• Ultrasound: useful to help distinguish acute epididymitis from testicular torsion if immediately accessible but must not delay intervention or exploration if testicular torsion is suspected.⁵
• Anatomical abnormalities of the urinary tract are common in the group infected with Gram negative enteric organisms and further investigation of the urinary tract should be considered in all such patients, especially in those older than 50 years.

• If any possibility of torsion, arrange urgent urology opinion.
• If possible STD (e.g. younger age, multiple partners or new partner):⁶
  • Refer urgently to genito-urinary clinic for full STD screen, treatment and contact tracing.
  • Advise to avoid unprotected sex until treatment and follow up, including tracing and treating sexual contacts, have been completed.
• If older age group and no recent change of partner, treat as for complicated UTI as below.

General advice

• Advise rest, scrotal elevation and supportive underwear.
• Ice packs.
• Anti-inflammatory agents.
• Analgesics.

Drugs

• If urine dipstick negative, and/or high suspicion of urethritis, start empirical treatment before culture results are available:⁷
  • Uncomplicated gonorrhoea: cefixime (unlicensed indication) or ciprofloxacin.
  • Uncomplicated genital chlamydial infection, non-gonococcal urethritis and non-specific genital infection: doxycycline or azithromycin (treat with doxycycline for 7 days or with azithromycin as a single dose); alternatively treat with erythromycin for 14 days.
• If urine dipstick positive and most likely enteric organisms, treat as for 'complicated UTI', e.g. trimethoprim or ofloxacin for 14 days.⁶

Surgical

• Scrotal exploration if a torsion or tumour cannot be ruled out and for the complications of acute epididymitis and orchitis (e.g. abscess, testicular infarction).⁸

• Scrotal abscess.
• Testicular infarction: cord swelling can limit testicular artery blood flow.
• Recurrence.
• Chronic epididymitis.
• Sterility is uncommon after acute epididymitis, although the documented true incidence is unknown. Disturbances in the sperm quality are usually transient.
• More important is the far less common azoospermia:
  • Caused by the epididymal duct obstruction observed in untreated and improperly treated men with epididymitis.
  • The incidence of this condition is unknown.