INTRODUCTION	Section 2 of 11
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Background: Acute epididymitis is an inflammation of the epididymis. It is a significant cause of morbidity and is frequently observed by urologists, emergency medicine practitioners, and primary care physicians. When infection is severe and extends to the adjacent testicle, acute epididymo-orchitis is typically present. Chronic epididymitis refers to epididymal pain and inflammation (usually without scrotal swelling) that lasts for more than 6 months. Much less common, orchitis is an acute inflammatory reaction of only the testes, exclusive of epididymitis. Hippocrates first described mumps orchitis during the fifth century BC.

Pathophysiology: Acute epididymitis is thought to be caused by a retrograde passage of infected urine from the prostatic urethra to the epididymis via the ejaculatory ducts and vas deferens. Obstruction of the prostate or urethra and congenital anomalies creates a predisposition for sterile or urethro-vasal reflux, which normally does not occur. (The oblique angle of the ejaculatory ducts through the dense prostatic tissue usually prevents reflux.)

Instrumentation and indwelling catheters are common risk factors for acute epididymitis. Urethritis or prostatitis can also coexist. Tuberculous epididymitis may be the presenting feature of genitourinary tuberculosis (TB), which occurs through hematogenous spread. Orchitis differs from epididymitis in that a viral pathogen (mumps) is an important factor.

Reflux 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.

Frequency:

• In the US: An estimated 1 in 1000 men is affected yearly, and there are more than 600,000 medical visits per year for acute epididymitis. The mumps, measles, and rubella (MMR) vaccine has markedly reduced the incidence of mumps orchitis.

• Internationally: In the United Kingdom, there are 13,000 medical visits per year for acute epididymitis.

Race: Epididymitis and orchitis have no predilection for any racial or ethnic group.

Age:

• Acute epididymitis most commonly occurs in patients aged 15-30 years and patients older than 60 years. Childhood (prepubertal) epididymitis is rare, and testicular torsion is much more common in this age group.

• Structural urologic abnormalities are common in children and in men older than 40 years with acute epididymitis. Adults usually have bladder outlet obstruction (BOO) or urethral stricture; children may have an ectopic ureter, ectopic vas deferens, prostatic utricle, urethral duplication, posterior urethral valves, urethrorectal fistula, detrusor sphincter dyssynergia, or vesicoureteral reflux. According to the study from Merlini et al, 7 of 11 infants with documented bacteruria had reflux or urogenital malformations, while only 3 of 14 children older than 1 year had associated anatomical abnormalities.

• Mumps orchitis occurs in 20-40% of postpubertal boys with the mumps; it is rare in prepubertal boys.

	CLINICAL	Section 3 of 11
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography

History:

• Acute epididymitis and orchitis

• Gradual onset of scrotal pain and swelling

• Dysuria, frequency, urgency

• Fever and chills occur in only 25% of patients with acute epididymitis.

• Urethral discharge may precede acute epididymitis by more than 30 days or may not occur at all.

• Mumps orchitis

• Fever, malaise, and myalgia

• Parotiditis typically precedes the onset of orchitis by 3-5 days.

• Subclinical infections occur in 30-40% of patients.

Physical:

• Acute epididymitis

• Tenderness and induration first occur in the epididymal tail, then the body, and then the spermatic cord (funiculitis) or the ipsilateral testis (epididymo-orchitis).

• Prehn sign: Elevation of the affected hemiscrotum relieves the pain of epididymitis and exacerbates the pain of torsion. Manual detorsion of the affected testis may dramatically reduce pain in children with torsion.

• Physical examination findings may be unable to distinguish acute epididymitis from testicular torsion because early torsion also involves only the epididymis. A normal cremasteric reflex makes testicular torsion less likely.

• Acute epididymitis is bilateral in 5-10% of the patients.

• Erythema and mild scrotal cellulitis may be present.

• A reactive hydrocele is frequent with advanced epididymo-orchitis, which makes a scrotal examination difficult.

• TB can cause focal epididymitis, a draining sinus, or classical beading of the vas deferens with extensive involvement. Orchitis rarely occurs without epididymitis in TB.

• Orchitis

• Testicular enlargement, induration, and a reactive hydrocele commonly occur.

• The epididymis is not tender.

Causes:

• Etiology of acute epididymo-orchitis

• Nonspecific bacterial infections: Urinary coliforms (eg, Escherichia coli, pseudomonads) are more common in children and in men older than 40 years. Systemic infections from Haemophilus influenzae or Neisseria meningitides are rare. TB can occur in endemic areas.

• Sexually transmitted diseases (STDs): Chlamydia is most commonly identified (50%). Neisseria gonorrhoeae, Ureaplasma urealyticum, Treponema pallidum, Trichomonas, and Gardnerella vaginalis are also observed.

• Sterile reflux or urethro-vasal reflux may occur.

• Obstruction: Adults older than 40 years usually have a BOO (eg, benign prostatic hyperplasia [BPH]) or urethral stricture; children may have various congenital abnormalities or functional voiding problems.

• Amiodarone epididymitis is secondary to drug concentration, usually in the head of the epididymis, and can occur in as many as 3-11% of patients on the drug. This is a dose-dependent phenomenon, and typically occurs at dosages greater than 200 mg daily. Histological analysis reveals focal fibrosis and lymphocytic infiltration of epididymal tissues.

• Trauma to the scrotum can be a precipitating event.

• Other rare infections (eg, brucellosis, coccidioidomycosis, blastomycosis, cytomegalovirus (CMV), candidiasis, CMV in HIV) usually occur in immunocompromised hosts.

• Etiology 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: T pallidum, Mycobacterium tuberculosis, Mycobacterium leprae, Actinomyces, and fungal diseases are rare.

• Trauma

• Idiopathic