Basics
Description
Epididymitis is an acute inflammation of the epididymis that can cause severe scrotal pain. It is important to differentiate epididymitis from testicular torsion or testicular appendage torsion.
Epidemiology
- Epididymitis is the most common cause of acute scrotum, approximately 37-65% of cases. The incidence ranges between 0.8 and 1.2 cases/1,000 persons per year.
- There is a bimodal distribution with a peak in incidence in infants younger than 1 year of age and peripubertal boys.
Risk Factors
Urologic manipulation (cystoscopy, intermittent self-catheterization, surgery of the urethra)
Pathophysiology
- The majority of epididymitis is idiopathic (73%).
- Viral epididymitis: 2nd most common cause
- Urinalysis and culture are negative.
- Often elevated titers of enterovirus, Mycoplasma pneumoniae, and adenoviruses
- New research shows that some epididymitis might be due to postinfectious inflammation, as 50% of patients had respiratory symptoms within 1 month of presentation and presentations appear to peak in concert with rotavirus and enterovirus.
- Bacterial epididymitis: 2-6% of cases and is related to age
- Due to ascending infection from the urethra or bladder, reflux of infected urine into the vas deferens, or hematogenous dissemination
- Infants <1 year of age
- Typically due to genitourinary anomalies (73% vs. 21% in children >1 year of age)
- Abnormalities include meatal stenosis, neurogenic voiding dysfunction, urethral stenosis, posterior urethral valves, ectopic ureter.
- Typical bacteria include Escherichia coli, Klebsiella, and Enterococcus.
- Postpubertal sexually active boys may have infection with sexually transmitted diseases such as gonorrhea or chlamydia.
- Chemical epididymitis: due to reflux of sterile urine into the vas deferens or drugs (amiodarone)
- Posttraumatic
Commonly Associated Conditions
- Systemic serositis (familial Mediterranean fever, sarcoidosis, Kawasaki disease)
- Systemic vasculitis (Henoch-Sch ¶nlein purpura, polyarteritis nodosa)
Diagnosis
History
- It is not always possible to distinguish between testicular torsion, testicular appendage torsion, and epididymitis based on history and physical exam.
- Duration of symptoms is longer than in testicular torsion, typically >12 hours.
- The majority of patients complain of scrotal pain (91-98%), scrotal swelling (83%), and scrotal erythema (74%).
- Patients who have bacterial epididymitis are more likely to have prior urologic history than patients without bacterial epididymitis (73% vs. 0%).
- 16-33% of patients have a fever, almost always in bacterial epididymitis
Physical Exam
Inflamed, swollen scrotum with localized epididymal pain early in the course that can spread to generalized testicular inflammation late in the course.
Diagnostic Tests & Interpretation
Lab
- Urinalysis and urine culture are only positive in a minority of presentations (7% and 1-6% respectively), but they should be sent for all patients to help guide therapy if they are positive for bacterial epididymitis.
- WBC, CRP, and ESR are most elevated in systemic serositis or vasculitis.
- Any sexually active boy or boy with an unclear sexual history should have gonorrhea and chlamydial testing performed.
Imaging
- Epididymitis typically appears as an enlarged epididymis with hypervascular flow and mixed echogenicity with reactive fluid.
Alert
For acute scrotum, perform scrotal ultrasound with Doppler to differentiate between testicular torsion, testicular appendicular torsion, or epididymitis.
Differential Diagnosis
- Testicular torsion
- Testicular appendage torsion
- Incarcerated inguinal hernia
- Hydrocele
- Systemic vasculitis
- Recent urologic surgery
- Idiopathic scrotal edema
- Testicular tumor
- Appendicitis
- Mumps orchitis
Treatment
General Measures
Given that the majority of acute epididymitis is nonbacterial, initial treatment should be supportive with analgesics, nonsteroidal anti-inflammatory drugs, bed rest, scrotal ice packs, and scrotal elevation.
Medication
- Any children younger than 1 year of age or with pyuria should be empirically begun on antibiotics based on a local antibiogram.
- If a child has culture-proven bacterial epididymitis, they should be started on culture-sensitive antibiotics for a 2-week course.
Ongoing Care
Follow-up Recommendations
- Schedule for follow-up appointment in 2-4 weeks to ensure resolution of epididymitis.
- Recommend referral to pediatric urology.
- Children <1 year of age and any child with a positive urine culture should be evaluated with a renal bladder ultrasound to rule out genitourinary anomalies.
Additional Reading
- Cappele O, Liard A, Barret E, et al. Epididymitis in children: is further investigation necessary after the first episode? Eur Urol. 2000;38(5):627-630. [View Abstract]
- Halachmi S. Inflammation of the gonad in prepubertal healthy children. Epidemiology, etiology, and management. ScientificWorldJournal. 2006;6:1081-1085. [View Abstract]
- Makela E, Lahdes-Vasama T, Rajakorpi H, et al. A 19-year review of paediatric patients with acute scrotum. Scand J Surg. 2007;96(1):62-66. [View Abstract]
- Somekh E, Gorenstein A, Serour F. Acute epididymitis in boys: evidence of post-infectious etiology. J Urol. 2004;171(1):391-394; discussion 394. [View Abstract]
- Tekgul S, Riedmiller E, Gerharz P. Guidelines on Paediatric Urology. European Society for Paediatric Urology. 2008. http://www.uroweb.org/fileadmin/user_upload/Guidelines/19%20Paediatric%20Urology.pdf. Accessed June 23, 2014.
Codes
ICD09
- 604.90 Orchitis and epididymitis, unspecified
- 604.99 Other orchitis, epididymitis, and epididymo-orchitis, without mention of abscess
- 604.91 Orchitis and epididymitis in diseases classified elsewhere
ICD10
- N45.1 Epididymitis
- N45.3 Epididymo-orchitis
- N45.4 Abscess of epididymis or testis
- N45.2 Orchitis
SNOMED
- 31070006 Epididymitis (disorder)
- 43491000 Acute epididymitis
- 236768005 Chronic epididymitis
- 197994001 epididymitis associated with another disorder (disorder)
FAQ
- Q: What is the best empiric antibiotic?
- A: Empiric antibiotic choice should be based on local antibiogram. Typically reasonable choices include cephalexin, sulfamethoxazole and trimethoprim (Bactrim, Septra), or fluoroquinolone.
- Q: What should be done if the epididymitis has not resolved after 2 weeks?
- A: The child should have repeat urinalysis and urine culture to ensure he or she has not developed a resistant bacterial infection and repeat scrotal ultrasound to ensure he or she has not developed an abscess.
- Q: What is a Prehn sign?
- A: A Prehn sign (named after Douglas T. Prehn, MD) is a historical diagnostic maneuver that was previously used to help diagnose epididymitis. This maneuver is inferior to Doppler ultrasound. To conduct the Phren maneuver, elevate the testicles from below. The elevation of the testes should decrease pain if it is due to epididymitis; however, it does not theoretically relieve pain due to testicular torsion.