Emphysematous epididymo-orchitis is a rarely reported entity with only a handful of case reports which still lacks a strong evidence for the existence of the disease. It is reported as a rare cause of acute scrotum encountered in poorly controlled diabetics. Pathology of this condition is unknown with few possible hypotheses postulated. Diagnosis is usually made by ultrasonography with CT done to confirm the diagnosis, evaluate the extent of emphysematous spread of infection and to rule out coexistent retroperitoneal source. It has a high mortality and requires emergent orchidectomy.
All case reports published had spontaneous presentation of sudden onset testicular pain which does not relieve with scrotal elevation. It is associated with local inflammation, i.e. swelling, reddening and local rise in temperature. There may be associated fever, leukocytosis, pyuria and bacteriuria.
Pathology of this entity is unknown with diabetes mellitus being a predisposing factor as with other emphysematous infections. Following hypotheses are postulated:
- coexistent retroperitoneal emphysematous infection adjacent to origin of testicular artery with involvement of ipsilateral testis
- rupture of sigmoid diverticula into the seminal vesicle as a source of air within the testis
Hyperechoic foci within the testicular parenchyma showing posterior dirty shadowing and reverberation artefacts or a curved hyperechoic line conforming to the globular shape of testis is seen on high resolution ultrasound of scrotum suggesting the diagnosis. This hyperechogenicity needs to be differentiated from testicular microliths, sutures and foreign body. Presence of posterior dirty shadowing, reverberation artefacts and clinical profile help differentiate these entities. There may be associated reactive hydrocoele, funiculitis and scrotal wall thickening with increased vascularity.
CT is the modality of choice to demonstrate intratesticular air. Hypodense foci or patchy areas (Hounsfield unit value around -1000) noted within the testicular parenchyma confirm the diagnosis. CT also helps in determining the extent of spread of infection. Also abdominal sections may point toward other associated conditions like sigmoid diverticulae and retroperitoneal emphysematous infections.
Can confirm the presence of air within the testis but is time consuming and does not add any further to the diagnosis. Thus MRI in these cases is not recommended as it delays the emergent orchidectomy.
Treatment and prognosis
Time is the key to successful management. Emergent orchidectomy is the treatment of choice with secondary management of predisposing condition like retroperitoneal infection or sigmoid diverticulae. Strict control of diabetes may help prevent this condition. Prognosis is usually worse.
Fournier gangrene with testicular involvement:
Differentiation between emphysematous epididymo-orchitis and Fournier gangrene with testicular involvement is a challenge even radiologically. Presence of air within the subcutaneous plane with necrotizing fasciitis of perineal, genital and perianal regions point towards this entity. This is rarely reported with such cases having a retroperitoneal source of infection highlighting the difference in arterial supply of the testis (testicular artery from aorta) and scrotal wall (branches from internal iliac artery).
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