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 head is the most affected region, and reactive hydrocoele and wall thickening are frequently present.
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 epididymus.
Treatment and prognosis
Complications of epididymo-orchitis include:
- vascular compromise due to increased intratesticular pressure resulting in testicular ischaemia and even infarction
- epididymal abscess
- testicular abscess
Differential considerations include
- isolated orchitis
- granulomatous epididymitis
- chronic epididymitis: enlarged epididymis with increased heterogeneous echogenicity
- testicular neoplasm: clinical presentation is usually different
Ultrasound - testicular and scrotal
- ultrasound (introduction)
testicular and scrotal ultrasound
unilateral testicular lesion
- testicular torsion
- testicular rupture
- germ cell tumours of the testis
- sex cord / stromal tumours of the testis
- bilateral testicular lesion
- paratesticular lesions
- tubular ectasia of the rete testis
- cystadenoma of the rete testis
- testicular sarcoidosis
- testicular tuberculosis
- spermatic cord
- fibrous pseudotumour of the scrotum
- scrotal leiomyosarcoma
- testicular adrenal rest tumours (TARTs)
- tunica vaginalis testis mesothelioma
- splenogonadal fusion
- unilateral testicular lesion
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