Case report: role of bedside ultrasonography in early diagnosis of myonecrosis rapidly developed in deep soft tissue infections.

BACKGROUND: Myonecrosis can rapidly develop in soft tissue necrotizing infections, often with initial sparing of the skin. Despite the improvements in management of necrotizing soft tissue infections, mortality remains high, according to the location, microbial agents and comorbidities, ranging between 17 and 46 %. A prompt diagnosis represents the greatest challenge for the emergency physician. CASE REPORT: We describe the case of a patient with a history of hypertension and arrhythmia who developed nonclostridial necrotizing fasciitis with extensive myonecrosis, after articular infiltration procedure. A bedside focused ultrasonography (US) revealed disappearance of the regular fibrillar architecture of the long head of biceps muscle, with diffuse abnormal hyperechogenicity assembled in a "clod pattern". Computed tomography (CT) of the right arm did not depict muscle involvement, but showed a small gas collection around the shoulder, spreading to the subclavian region behind the major pectoral muscle. Necrotizing fasciitis with wide myonecrosis was confirmed by surgical debridement. Microbiological results showed a Staphylococcus aureus infection, managed by a selected antibiotic therapy. The patient was discharged after a small period of mechanical ventilation.
CONCLUSION: This is the first report of a previously healthy patient developing a nonclostridial necrotizing fasciitis with extensive myonecrosis attributable to infiltrative procedure and detected early by bedside US in emergency department. The role of bedside US in the emergency setting may save time for the prompt management of life-threatening necrotizing infections.