Bacterial Pyomyositis in the Neck Due to Bacteroides Fragilis

Bacterial pyomyositis is characterized by the formation of abscesses in skeletal muscle groups, frequently in the lower extremities. It is most prevalent in tropical climates and associated with Staphylococcus aureus. The presentation of pyomyositis in the neck is rare. We present a unique case of pyomyositis caused by a gut bacterium, Bacteroides fragilis. Additionally, the case highlights the difficulty in identifying the cause of spread of the bacteria from the gut to the affected musculature. A 77-year-old diabetic Caucasian male presented with progressive bilateral neck swelling and limited range of motion of the neck. CT imaging confirmed a peripherally enhancing sternocleidomastoid abscess, right pectoralis major muscle abscess, and a hypodense fluid collection found in the anterior mediastinum and retrosternal space. The patient underwent exploration with incision and drainage of the abscess. Blood and tissue culture-confirmed Bacteroides fragilis. Subsequent abdominal CT imaging revealed a perforated ascending colon, which, is thought to be responsible for the source of the bacterium. Bacterial pyomyositis is a rare condition and if not treated early can lead to sepsis and death. We present a rare case of bacteria from a gastrointestinal (GI) source that has not been reported in the literature. This highlights the importance of a thorough evaluation of a source of infection in patients with pyomyositis, especially in the setting of atypical microbes.