Emphysematous epididymo-orchitis

Emphysematous epididymo-orchitis is a rarely reported entity with only a handful of case reports. It is reported as a rare cause of acute scrotum encountered in poorly controlled diabeticsgas-forming epididymo-orchitis. The pathology of this condition is unknown with few possible hypotheses postulated. The diagnosis is usually made by ultrasonography with CT acquiredas an adjunct, to confirm the diagnosis, evaluate theits extent of emphysematous spread of infection and to rule out a coexistent retroperitoneal sourceinfective focus. It carrieshas a high mortality rate and requiresusually necessitates emergent orchidectomy.

Clinical presentation

All case reports published described adescribe 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, leucocytosis, pyuria and(pus in the urine) and bacteriuria.  

Pathology

Pathology of this entity is unknown with diabetes mellitus being a key predisposing factor as within most cases (as for other emphysematous infections). The following hypotheses are postulated:

• coexistent retroperitoneal emphysematous infection adjacent to the origin of the testicular artery with involvement of the ipsilateral testis
• rupture of sigmoid diverticula into the seminal vesicle as a source of air within the testis

Radiographic features

Ultrasonography

Hyperechoic foci within the testicular parenchyma showing posterior dirty shadowing and reverberation artifacts 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 bodies. The presence of posterior dirty shadowing, reverberation artifacts and clinical profile help differentiate these entities. There may be an associated reactive hydrocoelehydrocele, funiculitis and scrotal wall thickening with increased vascularity.

CT

CT is the modality of choice to demonstrate intratesticular airgas. Hypodense foci or patchy areas (Hounsfield unit value around(~ -1000HU) noted within the testicular parenchyma confirm the diagnosis. CT also helps in determining the extent of spread of infection. The images may also point toward other associated conditions like sigmoid diverticulaediverticula and retroperitoneal emphysematous infections.

MRI

MRI can confirm the presence of airgas 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 conditions like retroperitoneal infection or sigmoid diverticulaediverticula. StrictGood glycaemic control in the context of diabetes mellitus may help prevent thisthe condition. The prognosis is usually worse.

Differential diagnosis

• Fournier gangrene with testicular involvement 
  • presence of airgas within the subcutaneous plane with necrotising 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)