A 40-year-old man presented with painful swelling of the right side of his scrotum and history of fever of two days duration. Swelling and tenderness in the right side of scrotum on local examination.
High resolution ultrasonography of the scrotum was done.
Longitudinal section of the right side of scrotum shows the right Testis in normal axis (lie), enlarged with inhomogeneous hypoechoic echotexture. Scrotal wall oedema is seen.
Transverse section of the scrotum shows both testes in normal axis (lie). Oedematous right testis with altered echotexture. Scrotal wall oedema on the right side.
Colour Doppler Ultrasonogram shows marked increase in right testicular blood flow.
Colour Doppler Ultrasonogram of the normal left testis with the same Doppler settings as for the right side shows normal intratesticular vascularity.
Diagnosis: Acute Orchitis.
Inflammatory causes of scrotal pain predominate in all age groups. Epididymitis usually results from descending infection, frequently associated with urinary tract infection. Genitourinary anomalies (such as ectopic ureter, ectopic vas deferens, or urethral stricture) may predispose a child to epididymitis. In pubertal boys and young adults, epididymitis most commonly results from sexually transmitted diseases. Less commonly, epididymitis may result from hematogenous infection, trauma, idiopathic granulomatous disease, and vasculitides, such as Henoch-Schönlein purpura and Kawasaki disease. Chemical epididymitis from amiodarone hydrochloride, an antiarrhythmic agent, has been described. With infectious epididymitis, the process begins in the tail and proceeds cephalad. [from Reference 2 below]
On US, the epididymis is enlarged and hypoechoic or heterogeneous in echotexture. Often there is a reactive hydrocele and scrotal wall thickening. Associated orchitis is seen in 20% of cases and may be diffuse or focal, characteristically seen as a crescentic hypoechoic lesion within the testicle, located at the periphery near the inflamed epididymis. Isolated orchitis is rare, and is usually a result of postviral or posttraumatic inflammation. [from Reference 2 below]
At color and power Doppler US, the hallmark of scrotal infection is hyperemia of the epididymis, testis, or both. Increased blood flow to the epididymis and testis at color Doppler US examination is a well-established criterion for the diagnosis of epididymo-orchitis. The sensitivity of color Doppler US imaging in detecting scrotal inflammation is nearly 100%. In 20% of cases of epididymitis and 40% of cases of orchitis, hyperemia is the diagnostic color Doppler US finding, because gray-scale US findings are normal. [from Reference 3 below]
References & Further Reading:
- Mayo Clinic article on Testicular Torsion.
- Chen P, John S. Ultrasound of the acute scrotum. Appl Radiol 2006;35: 9-17 [Full text article. Subscription required, free]
- Dogra VS, Gottlieb RH, Oka M, Rubens DJ. Sonography of the Scrotum. Radiology 2003 227: 18-36 [Full text article, free]
- Ragheb D, Higgins JL. Ultrasonography of the Scrotum: Technique, Anatomy, and Pathologic Entities. J Ultrasound Med 2002 21: 171-185. [Full text article, free in India. Subscription required for others.]
- Winter T. Ultrasonography of the scrotum. Appl Radiol 2002;31: 9-18 [Full text article. Subscription required, free]
- Goldman SM, Sandler CM. Genitourinary Imaging: The Past 40 Years. Radiology 2000 215: 313-324 [Full text article, free]