Diagnose on Sight: Post-traumatic Finger Pain

acute osteomyelitis Case: A 32-year-old male with a past medical history of diabetes presents with a 1 month history of finger pain after slamming his finger in a car door. 2 weeks after the initial incident he presented to the emergency department for worsening pain and received x-rays that were negative for acute fracture. Today he presents reporting pain radiating up the hand, arm, and into the shoulder, with associated chills. His labs are significant for hyperglycemia, hyponatremia, and an elevated erythrocyte sedimentation rate and c-reactive protein. His x-ray is seen here (figure 1 image courtesy of Daniel Rogan, MD). What is the diagnosis?