Necrotizing streptococcal myositis of the upper extremity: a case report

Necrotizing myositis is a rare but life-threatening soft-tissue infection characterized by rapidly spreading inflammation and subsequent necrosis of the affected tissue. The myositis is often caused by toxin-producing, virulent bacteria such as group A β-hemolytic streptococcus and associated with severe systemic toxicity. It is rapidly fatal unless diagnosed promptly and treated aggressively. However, necrotizing myositis is often initially misdiagnosed as a more benign soft-tissue infection as such fulminant, invasive muscle infections are rare with no more than 30 cases reported over the last century.

We illustrate the case of a 74-year-old male Caucasian initially presenting with a progressing swelling and gradually oncoming pain of the upper right extremity. Rapidly, livid discolorations of the skin, blisters, hypoesthesia and severe pain resistant to analgesics treatment developed accompanied by disruption of the arterial blood flow. Due to a manifest compartment syndrome the patient was admitted to theater for fasciotomy of the arm. After multiple revision surgeries wound closure was achieved using a pedicled, fasciocutaneous parascapular flap and a free, ipsilateral anterolateral thigh flap. Microbiological analysis revealed group A β-hemolytic streptococcus, histology a bacterial interstitial myositis with necrotic muscular fibers.

A high degree of clinical suspicion is necessary to avert potentially disastrous consequences of necrotizing myositis. Timely diagnosis, broad-spectrum antibiotic therapy, and aggressive surgical debridement of affected tissue are keys to the treatment of this serious, often life-threatening infection.