From the Guidelines
Epididymitis can be diagnosed using a combination of clinical history, physical examination, and imaging modalities, with ultrasound (US) being the established first-line imaging modality.
Diagnostic Methods
- Clinical History and Physical Examination: A thorough clinical history and physical examination are essential in diagnosing epididymitis, with symptoms such as scrotal pain, swelling, and redness being common presentations 1.
- Ultrasound (US): US is the primary imaging modality for diagnosing epididymitis, with high-resolution grayscale and color Doppler US allowing for prompt and accurate differentiation of scrotal emergencies 1. US findings in patients with epididymitis include an enlarged and hypoechoic epididymis due to edema, reactive hydroceles, and scrotal wall thickening, with color Doppler imaging showing increased blood flow corresponding to hyperemia.
- Laboratory Tests: Laboratory tests, such as nucleic acid amplification tests (NAATs) and cultures, can be used to identify the underlying cause of epididymitis, with Chlamydia trachomatis and Neisseria gonorrhoeae being common pathogens in men <35 years of age 1.
Important Considerations
- Differential Diagnosis: Epididymitis must be differentiated from other causes of acute scrotal pain, such as testicular torsion and torsion of the testicular appendage, which can have overlapping clinical presentations 1.
- Imaging Findings: US findings in epididymitis can be similar to those seen in testicular torsion, and correlation with clinical data, including laboratory markers for infection, is essential to distinguish between the two entities 1.
From the Research
Diagnostic Methods for Epididymitis
The diagnostic methods for epididymitis include:
- Physical examination and medical history review 2, 3
- Laboratory tests such as:
- Urinalysis and urine culture to detect bacterial infections 4, 5, 6
- Nucleic acid amplification testing (NAAT) for chlamydia, gonorrhea, and trichomonas 4
- Polymerase chain reaction (PCR) for sexually transmitted infections (STIs) and 16S ribosomal DNA (rDNA) analysis 5
- Blood tests such as C-reactive protein (CRP) to assess inflammation 6
- Imaging studies such as ultrasound may be used to rule out other conditions 3
Laboratory Testing
Laboratory testing is crucial in diagnosing epididymitis, particularly in identifying the underlying cause of the infection. Studies have shown that:
- Urine culture can detect bacterial growth in approximately 31% of patients with acute epididymitis 6
- NAAT can detect chlamydia, gonorrhea, and trichomonas in patients with epididymitis 4
- PCR and 16S rDNA analysis can detect STIs and other bacterial infections 5
- Elevated CRP levels can indicate bacterial epididymitis 6
Clinical Guidelines
Clinical guidelines recommend the use of empirical antimicrobial therapy in patients with acute epididymitis, particularly those with suspected bacterial infections 5. The choice of antibiotic therapy should be based on the suspected cause of the infection and local resistance patterns. Studies have shown that fluoroquinolones and group 3 cephalosporins are effective against common bacterial pathogens such as Escherichia coli 5.