Synchronous Subacromial and Subdeltoid Bursal Abscess and Pyomyositis of Rotator Cuff Muscles Caused by Viridans Streptococcus

The most common causal organism in septic bursitis and pyomyositis is Staphylococcus aureus. Primary subacromial and subdeltoid abscess caused by viridans Streptococcus infection has never been reported and, to our knowledge, nor has diffuse pyomyositis of the rotator cuff associated with subacromial abscess. We describe the clinical presentation, radiological investigations and strategies for the management of a 56-year-old female who presented with purulent subacromial/subdeltoid bursitis and abscess formation in the rotator cuff muscles as a result of viridans Streptococcus infection. Because of its deep anatomic location, primary subacromial/subdeltoid septic bursitis and pyomyositis of rotator cuff muscles are rarely reported. The immunocompromise caused by diabetes mellitus presented a risk factor for the unusual infection observed in this patient. Magnetic resonance imaging aided the diagnosis. Treatment consisted of surgical debridement and drainage, with antibiotic administration, which resolved the infection without sequelae.