Diagnostic Ultrasound - Abdomen and Pelvis

Epididymitis/Orchitis
708
Diagnoses: Scrotum
– Other causes: Pseudomonas, Klebsiella, Proteus
mirabilis, Staphylococcus aureus, Mycobacterium
tuberculosis, Mumps virus
○ Bacterial seeding occurs directly in cases with
genitourinary (GU) anomaly and presumably
hematogenously in cases without demonstrable
anomaly
○ Primary orchitis is rare and caused by mumps (usually
bilateral)
○ Traumatic epididymitis: Similar findings as infectious
epididymitis
– However, patient will have preceding history of scrotal
trauma ± additional traumatic features such as
hematocele &/or testicular injury
– Conservative management: Antibiotics not needed
– Should not be confused with infectious epididymitis
○ Drugs such as amiodarone hydrochloride may cause
chemical epididymitis
○ Strenuous physical activity
○ Pelvic/inguinal surgery
Staging, Grading, & Classification
• Epididymitis: Isolated epididymitis, focal or diffuse
○ Acute/chronic epididymitis
• Orchitis or combined epididymitis & orchitis
○ Primary: Isolated orchitis (may be seen in boys with
mumps)
○ Secondary: Infection spread from adjacent epididymis
○ Acute/chronic orchitis or epididymo-orchitis
Gross Pathologic & Surgical Features
• Treated surgically only if abscess forms despite antibiotic
treatment
Microscopic Features
• Inflammatory infiltrate of testis and epididymis
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Commonest cause of acute scrotal pain in adolescent
boys and adults
○ Scrotal swelling, erythema; fever; dysuria
– Prehn sign: Scrotal pain due to epididymo-orchitis is
usually relieved after elevation of scrotum over
symphysis pubis → may help clinically to differentiate
from torsion
○ Associated lower urinary tract infection and its
symptoms, urethral discharge
• Other signs/symptoms
○ Pyuria (95%), prostatic tenderness (infrequent)
○ ↑ CRP can help distinguish epididymo-orchitis from
testicular torsion (sensitivity 96%, specificity 94%)
○ Positive urinalysis for WBC and bacteria; may have
elevated WBC
Demographics
• Age
○ Most commonly 15-35 years
• Epidemiology
○ Most frequently seen in sexually active young men; also
seen in infants and boys
Natural History & Prognosis
• Prognosis excellent if treated early with antibiotics
• Complications
○ Abscess formation (epididymal abscess: 6%, testicular
abscess: 6%), microabscesses are usually seen in lowgrade
infection such as tuberculosis and in
immunocompromised host
○ Testicular infarction
– Venous infarction: Due to venous outflow obstruction
– Thrombosis of main testicular artery or its branches
secondary to chronic inflammation
– Gangrene is rare but a known complication
○ Gonadal vein thrombosis
○ Pyocele
○ Late testicular atrophy (21%)
○ Recurrent infection may lead to infertility
Treatment
• Antibiotic therapy; follow-up scans to exclude abscess if no
improvement
• Work-up for GU anomalies in younger children and
recurrent cases
• Bed rest, scrotal elevation, analgesics
DIAGNOSTIC CHECKLIST
Consider
• Torsion if low or absent flow within testis
Image Interpretation Pearls
• Hyperemic and enlarged epididymis &/or testis
SELECTED REFERENCES
1. Avery LL et al: Imaging of penile and scrotal emergencies. Radiographics.
33(3):721-40, 2013
2. Boettcher M et al: Differentiation of epididymitis and appendix testis torsion
by clinical and ultrasound signs in children. Urology. 82(4):899-904, 2013
3. D'Andrea A et al: US in the assessment of acute scrotum. Crit Ultrasound J. 5
Suppl 1:S8, 2013
4. Yusuf G et al: Global testicular infarction in the presence of epididymitis:
clinical features, appearances on grayscale, color Doppler, and contrastenhanced
sonography, and histologic correlation. J Ultrasound Med.
32(1):175-80, 2013
5. Aganovic L et al: Imaging of the scrotum. Radiol Clin North Am. 50(6):1145-
65, 2012
6. Yagil Y et al: Role of Doppler ultrasonography in the triage of acute scrotum
in the emergency department. J Ultrasound Med. 29(1):11-21, 2010
7. Thinyu S et al: Role of ultrasonography in diagnosis of scrotal disorders: a
review of 110 cases. Biomed Imaging Interv J. 5(1):e2, 2009
8. Trojian TH et al: Epididymitis and orchitis: an overview. Am Fam Physician.
79(7):583-7, 2009
9. Aso C et al: Gray-scale and color Doppler sonography of scrotal disorders in
children: an update. Radiographics. 25(5):1197-214, 2005
10. Dogra V et al: Acute painful scrotum. Radiol Clin North Am. 42(2):349-63,
2004
11. Dogra VS et al: Sonography of the scrotum. Radiology. 227(1):18-36, 2003
12. Chung JJ et al: Sonographic findings in tuberculous epididymitis and
epididymo-orchitis. J Clin Ultrasound. 25(7):390-4, 1997
13. Gordon LM et al: Traumatic epididymitis: evaluation with color Doppler
sonography. AJR Am J Roentgenol. 166(6):1323-5, 1996
14. Bukowski TP et al: Epididymitis in older boys: dysfunctional voiding as an
etiology. J Urol. 154(2 Pt 2):762-5, 1995