Presentation
Five days of progressive left shoulder/upper arm pain with no history of trauma. She was systemically well but noted to be febrile.
Patient Data
No fracture or malalignment identified.
Along the proximal diaphysis of the humerus there is a subperiosteal collection.
There is extensive enhancement along the periosteal and subperiosteal surface of the proximal humerus, extending from the proximal metaphysis to the mid shaft. There is also intramedullary enhancement and heterogeneity and generalized soft tissue edema of the muscles of the upper arm. The findings are likely to indicate osteomyelitis.
Case Discussion
Initial ultrasound imaging was reported as subperiosteal hematoma, however, with no history of trauma and significantly raised inflammatory markers, an MRI was requested which was suggestive of osteomyelitis and subperiosteal abscess. The patient was taken to theater and found to have subperiosteal frank pus at the lateral proximal humerus and frank pus within the humerus medullary cavity. Fluid, tissue and bone cultures grew Group A Streptococcus. The GAS was likely hematogenous spread from a recent boil the patient had on her lower leg.