Introduction
Background
Acute epididymitis, testicular torsion, and testicular tumors can have a common presentation of pain. Acute epididymitis is the most common condition that causes acute scrotal pain. Distinguishing between acute epididymitis and testicular torsion is important because their treatments differ significantly.
Pathophysiology
Usually, acute epididymitis is caused by Chlamydia trachomatis or Neisseria gonorrhoeae, which are sexually transmitted. In prepubertal boys and men older than 35 years, the disease is most frequently caused by Escherichia coli or Proteus mirabilis.
Other causes include tuberculosis (especially in patients with AIDS), sarcoidosis, brucellosis, and leprosy. Noninfectious causes include trauma and drugs such as amiodarone.
Mumps is the most common cause of orchitis and usually requires no intervention.
Frequency
United States
Acute epididymitis is the most common cause of acute scrotum in male adolescents.
International
As in the United States, acute epididymitis is the most common cause of acute scrotum in male adolescents.
Mortality/Morbidity
Complications of epididymitis and/or epididymo-orchitis include the following:
- Chronic epididymitis
- Infarction
- Infertility
- Abscess
- Atrophy
- Pyocele
Race
No racial predilection is reported.
Sex
Only males are affected.
Age
Adolescents and adults can be affected.
Anatomy
Normal testes develop in the celom and begin to descend into the scrotum at 36 weeks' gestation, guided by the contractile, cordlike structure called the gubernaculum testis. The epididymis and ductus deferens develop from the wolffian ducts.
At sonography, a normal adult testis has medium-level echoes and measures 5 x 3 x 2 cm. Septa extend from the tunica albuginea into the testicle, dividing the testes into lobules. The posterior surface of the tunica albuginea is reflected into the interior of the gland to form the incomplete septum known as the mediastinum of the testis. Each lobule is composed of many seminiferous tubules that open, via tubules (tubuli recti), into dilated spaces called the rete testes in the mediastinum. These, in turn, communicate via efferent ductules in the epididymal head.
The epididymis is composed of a head, body, and tail, the ducts of which continue as the vas deferens in the spermatic cord. The epididymis lies superior and lateral, along the posterior aspect of the testis; the head of epididymis is the most cephalic part.
Four testicular appendages have been described; however, only 2 are clinically relevant: the appendix of the testis (müllerian duct remnant) and the appendix of the epididymis, a wolffian duct remnant. Sonographically, the head of the epididymis is better depicted in the longitudinal view than in others. It is an isoechoic or slightly hypoechoic structure with medium-level echoes. Usually, the body of the epididymis is not identified at sonography in healthy adults. Sometimes, the epididymal tail is seen.
Presentation
Patients present with acute pain in the scrotum, which may be associated with fever and pyuria. Physical examination reveals an enlarged and tender epididymis that can be separated from the scrotum. The pain is relieved by elevating the scrotum to the symphysis pubis (Prehn sign). Usually, the cremasteric reflex is present.
Regarding the differential diagnosis, testicular torsion has a similar presentation. Torsion of the appendix of the testis also causes pain, but systemic symptoms are usually absent. Physical examination reveals the blue dot sign, which occurs in patients with torsion of the appendix of the testis. The Prehn sign is positive in patients with acute epididymitis and negative in patients with testicular torsion. The cremasteric reflex is present in patients with acute epididymitis and absent in patients with testicular torsion. Approximately 10% of the tumors may cause acute pain.
Preferred Examination
Sonography, clinical history taking, and physical examination are the mainstays in diagnosing acute epididymitis. The preferred imaging examination is ultrasonography, which is very useful in the detection of the epididymitis and/or epididymo-orchitis. Ultrasonography is helpful in excluding testicular torsion.
Differential Diagnoses
Testicle, Malignant Tumors
Testicle, Trauma
Testicular Torsion
More on Epididymitis |
 Overview: Epididymitis |
| Imaging: Epididymitis |
| Follow-up: Epididymitis |
| Multimedia: Epididymitis |
| References |
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References
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Further Reading
Keywords
epididymis, acute epididymitis, epididymo-orchitis, acute scrotum, acute scrotal pain, testicular torsion, Chlamydia trachomatis, C trachomatis, Neisseria gonorrhoeae, N gonorrhoeae, Escherichia coli, E coli, Proteus mirabilis, P mirabilis, Prehn sign
