Subscapularis pyomyositis, a rare cause of shoulder pain, in a patient without apparent risk factors: A case report.

INTRODUCTION: Pyomyositis, previously tropical, now seen more in temperate zones, particularly in those with HIV, cancer, or diabetes. Even healthy individuals, like athletes, can get it post-exercise or minor injuries. Our patient, in a desert-like area, adds an interesting aspect. Diagnosing is challenging due to deep tissue occurrence and subtle symptoms, leading to delayed detection and higher risks of morbidity.

PRESENTATION OF CASE: A 45-year-old female patient presented with acute left shoulder pain and functional impairment, exacerbated by movement. Clinical examination revealed tenderness upon deep palpation in the left upper posterior thoracic region and restricted range of motion of the affected shoulder.

DISCUSSION: Initial assessments at medical facilities suggested musculoskeletal strain and lower cervical disc prolapse despite normal X-ray results. MRI scans confirmed a developing abscess in the left subscapularis muscle, with intraoperative findings revealing extensive purulent fluid and necrotic tissue. Four surgeries drained the abscess and treated fat necrosis, with tailored antibiotics administered. Subsequent arthroscopy showed fibrous tissue, swelling, and inflammation. At the 3-month check-up, she had fully recovered, experiencing no pain or complications, and had almost regained full range of motion.

CONCLUSION: Shoulder pyomyositis presents diagnostic challenges, causing delayed treatment. This case highlights the importance of considering pyomyositis in severe shoulder pain cases, even without typical risk factors or inconclusive X-rays. Timely recognition, surgical drainage, tailored antibiotics, and physical therapy are crucial. An interdisciplinary approach with orthopaedic surgery, infectious disease specialists, radiology, and physical therapy is vital for comprehensive management, improving outcomes, and reducing complications.