An 80-year-old man presented to the emergency department in August 2016 with a 2-day history of painful scrotal swelling and fever. There was no history of trauma. He had a history of hypertension, diabetes mellitus and bullous pemphigoid, and was taking long-term steroid therapy. Upon presentation, the patient had a fever of 38.8°C and fast atrial fibrillation with a heart rate of 170 beats per minute. Blood pressure was 149/104 mm Hg. Physical examination of the patient revealed scrotal skin erythema and a firm left scrotal swelling that was tender on palpation. No cough impulse could be elicited. His white cell count was 21.8 × 109 /L and blood glucose level was 21.6 mmol/L. Ultrasound of the left hemiscrotum showed a fluid collection with hyperechoic interfaces and ring-down artefact suggestive of the presence of gas, obscuring the underlying structures (Fig 1). Subsequent non-contrast computed tomographic scan of the pelvis confirmed that the mottled gas and fluid density were confined to the left hemiscrotum (Fig 2a). The left testis and epididymis were poorly delineated. There was no gas density in the subcutaneous layer of the scrotum or perineum or in the intraperitoneal cavity. There was also no evidence of indirect inguinal hernia (Fig 2b). A diagnosis of emphysematous epididymo-orchitis was made. Emergency surgery was arranged a few hours after imaging. Intra-operatively, gas and pus were seen within the left tunica vaginalis. The left epididymis was necrotic and almost destroyed but the left testis was relatively spared with friable tissue and patches of necrosis (Fig 3). Drainage of pus and left orchidectomy were performed. Pus culture revealed Escherichia coli. The patient subsequently developed septic shock and died 3 days after the operation.

Emphysematous cholecystitis, pyelonephritis, and cystitis are not uncommonly seen in patients with poorly controlled diabetes mellitus. It is nonetheless rare to see gas-forming infection of the epididymis and testis although this is also reported to be associated with diabetes mellitus.1 2 3 Long-term use of steroid in our patient may have been an additional risk factor due to immunosuppression. Based on the clinical presentation and ultrasound findings of our patient, the main differential diagnoses included Fournier’s gangrene and incarcerated indirect inguinal hernia. Computed tomographic scan was very helpful in delineating the definitive diagnosis. Gas pockets confined to the scrotal sac without involvement of the subcutaneous layer of the perineum virtually excluded the possibility of Fournier’s gangrene. Incarcerated indirect inguinal hernia was excluded due to the absence of bowel loops in the scrotal sac.

When a diabetic patient presents with acute scrotal pain and features of infection, careful examination during the initial ultrasound scan for the presence of gas within the scrotum is essential as this will alter the subsequent management plan as it implies a much poorer prognosis than non–gas-forming epididymo-orchitis.

In conclusion, emphysematous epididymo-orchitis is an uncommon but life-threatening disease. Ultrasound and computed tomographic scan are essential to identify this entity for early treatment.

All authors have made substantial contributions to the concept or design of this study; acquisition of data; analysis or interpretation of data; drafting of the article; and critical revision for important intellectual content.

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

All authors have disclosed no conflicts of interest. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.

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2. Mandava A, Rao RP, Kumar DA, Naga Prasad IS. Imaging in emphysematous epididymo-orchitis: a rare cause of acute scrotum. Indian J Radiol Imaging 2014;24:306-9. Crossref

3. Hegde RG, Balani A, Merchant SA, Joshi AR. Synchronous infection of the aorta and the testis: emphysematous epididymo-orchitis, abdominal aortic mycotic aneurysm, and testicular artery pseudoaneurysm diagnosed by use of MDCT. Jpn J Radiol 2014;32:425-30. Crossref