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Epididymitis is inflammation of the epididymis that is either acute or chronic. The inflammation results in pain and swelling that occurs on the back of testicles. It is usually unilateral and can be caused by sexually transmitted infections. Common causing pathogens are Chlamydia trachomatis, Neisseria gonorrhea and syphilis. Non-sexually transmitted infections from Escherichia coli, staphylococci and streptococci more commonly occur in older men.

The Epididymis

The epididymis is a tightly coiled tubular structure that lies posterior to the testis. It has three main regions, the head, body and tail. The head is the most superior part and receives the sperm. The testes produce spermatozoa that flow into the epididymis and are partially stored there. The tail is the narrowest part and joins into the vas deferens.

The lining of the epididymis is pseudostratified columnar epithelium that is surrounded by smooth muscle and connective tissue. Two main types of cells, principal and basal cells, are present in the epithelium. The principal cells bear stereocilia that are microvilli, which increase surface area; this helps absorption of fluid and defective sperm. Sperm matures as it passes through the epididymis. After spending a month in the epididymis the sperm expires and are replaced. The defective and dead sperm is absorbed by the body and excreted.

The vas deferens passes superiorly and posteriorly to the testis and then winds antero-medially in an oblique fashion opening into the prostatic urethra via an opening known as the verumontanum. The seminal vesicles sit inferiorly to the vas deferens on each side and also open into the verumontanum in the prostatic urethra. The prostate sits inferiorly to the seminal vesicles and its central urethral portion surrounds the prostatic portion of the urethra.

The prostate and seminal vesicles produce the bulk of the seminal fluid. This is then combined with the sperm to form semen that is released upon ejaculation. Successful ejaculation is dependent on numerous factors. During ejaculation the vas deferens contracts and causes anterograde propulsion of the sperm to flow.

Right vas deferens - lateral-right view


Epididymitis can be classified as acute or chronic. Acute onset develops over a few days. Chronic epididymitis goes on for more than three months and this can be due to inflammation with or without infection and obstruction. Underlying causes of chronic epididymitis need to be investigated to rule out testicular cancer, varicocele or epididymal cyst.


  • In some cases epididymitis is idiopathic, and the causation is unknown.
  • In younger men usually less than 35 years of age epididymitis can be caused most commonly by sexually transmitted infection such as Chlamydia trachomatis, Neisseria gonorrhoea and syphilis. Older men more than 35 years old with urinary tract or prostate infections, bladder outlet obstruction and recent urological surgery can have epididymitis caused by enteric pathogens such as streptococci, staphylococci and E. coli. And some with systemic illness and immunosuppressed contact with tuberculosis can cause it.
  • Viral infections may cause epididymo-orchitis; in those who have not been immunised against Mumps can develop mumps orchitis. Other viruses associated are Coxsackie virus, echovirus and varicella zoster.
  • Vasculitic diseases such as Henoch-Schonlein purpura and Behcet’s syndrome have rarely presented with epididymo-orchitis. And another, rare yet reversible cause is from the use of amiodarone which is an anti arrhythmic drug.

Risk Factors

  • Epididymitis can be related to risk factors such as unprotected sexual intercourse. Men who have sex with men are at risk during unprotected anal intercourse.
  • Indwelling and intermittent urethral catheters and cystoscopic procedures can put patients at risk of infection. Urinary tract infections can spread to the epididymis leading to epididymitis.
  • Bladder outflow obstruction can occur in older men from benign prostatic hyperplasia, bladder neck obstruction, or urethral stricture formation. This puts patients at risk of higher pressures during urination and incomplete bladder emptying which leads to infection and spread to the epididymis.

Urinary bladder - lateral-right view

Signs and Symptoms

In acute onset, epididymis symptoms develop over a few days and last for less than six weeks. The swelling is usually unilateral. The area is painful and tender. There can be enlargement of the testis and is hot, red and swollen. Patients can experience lower urinary tract symptoms such as frequency and dysuria. Uncommon signs are urethral discharge, fluctuant swelling and fever. A useful sign to differentiate between testicular torsion and epididymitis is the cremasteric reflex. This reflex by the superior and medial aspect of the thigh being lightly stroked in any direction, the normal response should be the pulling of the testis ipsilaterally by the contraction of the cremaster muscle. The cremasteric reflex if normal before the onset of epididymitis symptoms will remain normal with the condition. On physical examination, the testicle is often elevated within the scrotum in a transverse rotated position in testicular torsion while it should be in a normal position in epididymitis.



  • Initial investigations are to gram stain and culture of the urethral secretions. The sample of secretions should swabbed before micturition. This test is very helpful in checking for gonococcal infection.
  • Then a urine dipstick test is required to check for white blood cells an indication of urinary tract infection. To follow urine microscopy and culture of the first void sample can be done to confirm urine dipstick results.
  • The test to check for Chlamydia and Gonorrhoea is nucleic acid amplification test (NAAT). This test amplifies and identifies microbial DNA. It is highly sensitive and specific in detecting viruses and bacteria causing epididymitis.
  • Colour duplex ultrasonography is useful as it visualises structure and blood flow, it has a high sensitivity and specificity in diagnosing epididymitis and very good at differentiating it with testicular torsion.


  • If symptoms do not subside after three days, treatment should be commenced. Once they have been ruled out treatment for epididymitis should be commenced.
  • Patients who have likely got a sexually transmitted infection should be treated with antibiotics; various hospitals will recommend different antibiotics. Usually, the treatment of choice for both gonorrhea and chlamydia are azithromycin or ceftriaxone plus doxycycline can be used.
  • For non-sexually transmitted infections caused by enteric bacteria, quinolone antibiotics such as ofloxacin are recommended.
  • For signs of sepsis, intravenous fluid replacement is required and to follow the sepsis protocol. For pain relief Non-steroidal anti-inflammatory drugs (NSAIDs) are prescribed. Patients are advised to have bed rest, scrotal elevation and cold compresses applied until signs of infection have subsided.
  • Persistent symptoms in chronic epididymitis lasting for more than three months may indicate: testicular abscess, infarction, underlying tumour or atypical infections like fungal or tuberculosis. It is important to investigate and treat for these differentials and treat accordingly.
  • Epididymectomy is the surgical removal of the epididymis; this may be recommended in cases that are severe with chronic infections and not successfully managed by medical intervention. However, this procedure will cause sterility.


  • Epididymitis left untreated can leave to severe complications that can cause permanent damage of the epididymis and lead ultimately to male infertility. Testicular infarction occurs due to occlusion of the testicular arteries. The inflammatory process in the epididymis can lead to extrinsic compression of structures around it. This can lead to infertility. Early treatment of epididymitis will prevent this from happening.Testicular artery - ventral view
  • The inflammatory process of epididymitis can lead to scarring and cause epididymal obstruction; this can also result in infertility. Corticosteroids have been beneficial in reducing the development of obstruction.
  • Another complication of not treating epididymitis early enough is abscess formation this is a rarely occurring and needs urgent antibiotic, or it may need to be surgically drained.
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Show references


  • Murray Longmore, Ian Wilkinson, Andrew Baldwin, Elizabeth Wallin: Oxford Handbook of Clinical Medicine, 9th Edition.
  • Martel Janelle: Epididymitis. Healthline Media. (accessed 21/05/2016)
  • Lab Tests Online: Chlamydia and Gonorrhea NAAT Screening. American Association for Clinical Chemistry. (accessed 21/05/2016)
  • David M. Whiley, John W. Tapsall, and Theo P. Sloots: Nucleic Acid Amplification Testing for Neisseria gonorrhoeae. 
  • David Schlossberg: Clinical Infectious Disease. Cambridge medicine.
  • W. John Spicer: Clinical Microbiology and Infectious Diseases: An Illustrated Colour Text. 2nd edition. Churchill Livingstone Elsevier.
  • Markus Hohenfellner, R.A. Santucci: Emergencies in Urology. Springer.

Author, Review and Layout:

  • Shahab Shahid
  • Uruj Zehra
  • Catarina Chaves


  • Right vas deferens - lateral-right view - Irina Münstermann
  • Urinary bladder - lateral-right view - Irina Münstermann
  • Testicular artery - ventral view - Hannah Ely
© Unless stated otherwise, all content, including illustrations are exclusive property of Kenhub GmbH, and are protected by German and international copyright laws. All rights reserved.
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