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Chapter 3: Epididymitis

Epididymitis is defined as inflammation of the epididymis and is generally caused by genitourinary infections, especially sexually transmitted infections.  Symptoms of epididymitis classically involve unilateral scrotal pain and swelling.  The testis is involved in most cases of acute epididymitis, commonly referred to as epididymoorchitis [Images 1, Image 2].  In approximately 10% of cases, trauma is the cause of acute epididymitis and, as an etiology, can usually be eliminated by history.  In patients with no history of scrotal trauma, important etiologic considerations include testicular torsion, epididymitis, tumor, and tuberculosis (the latter two diagnoses typically having more indolent presentations).  If the patient suspects he has a sexually transmitted disease, infection should be carefully considered as the cause of his symptoms.


Among sexually active men <35 years of age, most cases of epididymitis are due to Chlamydia trachomatis (CT) and the remainder to N. gonorrhoeae (GC).  Insertive anal intercourse is commonly associated with cases of epididymitis due to gram negative enteric pathogens including Escherichia coli or Pseudomonas spp.  In men >35 years of age, sexually transmitted epididymitis is relatively uncommon and causes due to urinary obstruction, (e.g., benign prostatic hyperplasia, urinary retention and urinary instrumentation) is more common.

Mycobacterium tuberculosis is responsible for more rare cases of chronic epididymitis in the U.S. and should be suspected in individuals who represent endemic geographic areas or are otherwise high risk given recent exposure.


History and Examination

Image 3-1. Epididymitis
Image 1.
Image 3-2. Epididymitis
Image 2.

The approach to the diagnosis of epididymitis in patients with unilateral scrotal pain and swelling begins with ruling out trauma by history and examination.

If torsion is strongly suspected, based primarily upon:

  • sudden onset,
  • excruciating pain,
  • age under 20,
  • available test results do not support a diagnosis of urethritis or urinary tract infection.

If torsion is suspected, immediately obtain urologic consultation and pursue radionuclide or Doppler flow studies to determine whether surgery is necessary.

If torsion is not strongly suspected, epididymitis becomes the most likely diagnosis based on:

  • less than 35 years of age,
  • history of recent urethritis or
  • urethritis (frequently asymptomatic),
  • no history of underlying genitourinary pathology of any other sort (prostatitis, recent catheterization, or other urologic procedure),
  • signs of epididymal or testicular inflammation (typically unilateral tenderness, swelling or increased warmth).

The evaluation of epididymitis should include one of the following (

  • Gram stain of urethral secretions demonstration ≥5 WBC per oil immersion field.  Gram stain is the preferred rapid test given its sensitivity and specificity for documenting urethritis and the presence or absence of gonococcal infection.
  • Positive leukocyte esterase test on first-void urine of microscopic examination of first-void urine sediment demonstrating ≥10 WBC per high power field.


Initially, separate patients suspected of having sexually transmitted pathogens from those suspected of having urinary tract infections by history, urethral Gram stain, and urinalysis.

Gonococcal and nongonococcal infection can be differentiated on the basis of the following:

  • Urethral Gram stain demonstrating ≥ WBC per oil immersion field. Gram stain is preferred given its highly sensitive and specific nature for diagnosing gonococcal infection (see Image 3 and 4)
  • Positive leukocyte esterase test on first-void urine or microscopic examination of first-void urine sediment demonstrating ≥10 WBC per high power field.
  • Urethral culture or nucleic acid amplification test for gonorrhea and C. trachomatis
image 3-3. Intracellular Gram-negative diplococci
Image 3.
Intracellular Gram-negative diplococci in urethral Gram stain
Image 3-4. Urethral Gram stain
Image 4.
Urethral Gram stain with 5 PMNs per high power field (nongonococcal urethritis)


For a more detailed discussion of these regimens and other treatment considerations, please refer to the CDC STD Treatment Guidelines at

Epididymitis-related symptoms range from mild to severe (fever, nausea, vomiting, abdominal and severe scrotal pain, marked epididymal and testicular swelling).  Patients with severe epididymitis should be hospitalized for initial management.  The remainder can be managed as outpatients. Bed rest, analgesics and scrotal elevation are recommended for all patients with acute epididymitis. Patients with pyuria and bacteriuria on urinalysis should be treated with appropriate antimicrobials.

The goals of treatment for either chlamydial or gonococcal epididymitis are:

  1. microbiologic cure of infection
  2. improvement of signs and symptoms of infection
  3. prevention of transmission of sexually transmitted pathogens
  4. decrease in risk of potential complications (e.g., infertility or chronic pain)

Recommended regimen

Ceftriaxone 250 mg IM in a single dose


Doxycycline 100 mg orally twice a day for 10 days

For acute epididymitis most likely caused by enteric organisms

Levofloxacin 500 mg orally once daily for 10 days


Ofloxacin 300 mg orally twice a day for 10 days

Both ceftriaxone with a fluroquinolone are recommended for populations at risk for both sexually transmitted and enteric organisms (e.g., men who have sex with men [MSM] who report insertive anal intercourse).


The frequency of follow-up should be individualized. Most patients should be reexamined 2 to 4 days after starting therapy.  Signs and symptoms that do not improve after three days of therapy requires re-evaluation and consideration of referral for specialty (urology) care.


Patients with confirmed epididymitis due to GC or CT should refer all sex partners in the 60 days preceding onset of their own symptoms for evaluation and treatment.  Patients should avoid sexual intercourse until after they and their sex partners are treated and until all symptoms have resolved.


Local complications include abscess formation and infarction of the testicle.  Infertility has occasionally been observed, mainly in cases with acute bilateral epididymitis. The risk of infertility after unilateral epididymitis has not been established but appears to be low.

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