Fournier\'s gangrene after a trivial foot injury

Clinical History

A 54-year-old Chinese male patient was referred to us with 3 days history of penetrating foot injury by a nail. He presented with swelling of scrotum and groin area, fever, mild respiratory distress and developed urinary retention within 3 days of injury. The patient was treated successfully with early surgical debridement and antibiotic cover.

Imaging Findings

The scrotal ultrasound was performed with high resolution 12 MHz linear probe in supine position. The scrotum, right groin and perineal area showed extensive oedema and wall thickening. The thickness measured approximately 3 cm. Multiple reverberating artefacts (dirty shadowing) were noted suggestive of presence of gas. No definite area of loculated collection was noticed. Both testes and epididymi were normal in size and echo-texture. Colour Doppler examination showed mildly increased blood flow in the periphery. All these findings were consistent with Fournier’s gangrene. In case ultrasound was inconclusive a CT would most likely be performed.

Discussion

Fournier’s gangrene is a mixed microbial infection which results in rapidly progressive necrotising fasciitis of the urogenital area. It is more prevalent in middle aged men with a male to female ratio of 5:1 [1]; however, no age is exempt as more than 50 cases have been reported in children [2]. It can be idiopathic or associated with diabetes mellitus, alcoholism, HIV infection, long-term use of steroids, chemotherapy, radio-therapy, various malignancies, and trauma. In 40-60% patients with Fournier’s gangrene, diabetes mellitus has been found to be an independent risk factor [3].
Patients may present with scrotal swelling, redness, pain, crepitus and perceptible stench. Fournier’s gangrene can become a vascular emergency after infection and leads to necrosis of skin and subcutaneous fatty tissue resulting in sloughing of the skin of scrotum. Testes become exposed to the surface, but remain healthy in most of the cases. Local infection and necrosis spreads upward into adjacent tissues and retroperitoneum. Severe sepsis can ensue, progressing rapidly into multiple organ failure and imminent death in a previously immunocompromised patient. Inflammatory markers are found to be raised, especially C reactive protein [4]. Blood cultures typically show more than three organisms in single cases. Gram positive bacteria such as E. coli, Staph aureus, Proteus species and gram negative organisms like Bacteroides, anaerobic streptococci and clostridia are the main culprits involved in the pathogenesis of Fournier’s gangrene [5].
Sonography can show oedema, thickening of the affected area, effusion and abscess formation with interspersed echogenic foci and dirty acoustic shadows, suggestive of the presence of gas [6]. CT scan may reveal the extension of disease process into the abdominopelvic cavity & retro-peritoneum [5]. Plain X-ray may depict air.
Empirical antibiotics are instituted after obtaining samples for culture and sensitivity, with change in regimen after their results. Extensive surgical debridements and abscess drainage improve the viability and subsequent salvage of the involved soft tissues. Mortality rate is very high in spite of aggressive antimicrobial and surgical treatments, ranging from 14.7% in general population [1] to 36% in diabetics [3]. Children have a very excellent cure rate.
The fulminant nature and devastating outcome of the disease with high mortality mandates an early suspicion even after a trivial trauma. Ultrasound examination can help us to diagnose the cases, whereas CT scans can delineate the extent of the disease in advanced scenarios. Every effort should be made to contain Fournier’s gangrene at an early stage.

Differential Diagnosis List

Final Diagnosis

Fournier's Gangrene after a trivial foot injury

URL:	https://www.eurorad.org/case/10845
DOI:	10.1594/EURORAD/CASE.10845
ISSN:	1563-4086