Epididymitis

Epididymitis refers to inflammation of the epididymis, and may be associated with inflammation extending to the testis itself, in which case the term epididymo-orchitis is used. This should be distinguished from isolated orchitis, which is by comparison much less common. 

There are two peaks of prevalence: <2 years of age and >6 years of age.

The clinical spectrum ranges from mild tenderness to a severe febrile process with acute unilateral scrotal pain. 

The infection usually originates in the bladder or prostate gland, spreads through the ductus deferens and the lymphatics of the spermatic cord to the epididymis, and finally reaches the testis, causing epididymo-orchitis.

The epididymal tail is the most affected region, and reactive hydrocoele and scrotal wall thickening are frequently present. As the infection spreads, it can ascend the body and later the head of the epididymis.

Increased size and, depending on the time of evolution, decreased, increased, or heterogeneous echogenicity of the affected organ are usually observed.

The inflammation produces increased blood flow within the epididymis, testis, or both.

Analysis of the epididymal waveform may reveal a low-resistance pattern as compared with the normal pattern.

Pertechnetate scintigraphy can be used in evaluating the acute scrotum. Increased perfusion and uptake of the scrotal contents is characteristic of epididymo-orchitis. In isolated epididymitis increased curvilinear activity is seen laterally, corresponding to the inflamed epididymis. 

Complications of epididymo-orchitis include:

Differential considerations include

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Article information

rID: 12749
System: Urogenital
Section: Pathology
Synonyms or Alternate Spellings:
  • Epididymo-orchitis
  • Epididymoorchitis

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Cases and figures

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    Case 1
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    Case 2: with epididymal abscess formation
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    Case 3
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     Case 4
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    Case 5: epididymo-orchitis
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    Case 6: on right side
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    Case 8
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    Case 9
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