Snapshot A 53-year-old man presents to the emergency department for fever, chills, and pain in the left foot. His symptoms began several weeks ago and have progressively worsened since. The pain is present with and without movement; he denies any recent trauma to the area. He feels feverish and experiences rigors at night. Medical history is significant for poorly controlled type II diabetes mellitus and peripheral vascular disease. On physical exam, there is a tender and erythematous ulcer on the pedal surface of the left foot. A probe-to-bone test is performed and demonstrates a hard and gritty surface. Laboratory testing is significant for an elevated erythrocyte sedimentation rate and C-reactive protein and leukocytosis. A plain radiograph demonstrates periosteal thickening and soft tissue swelling. Microbial cultures are obtained and he is started on empiric antibiotics. Introduction Clinical definition inflammation of the bone and bone marrow most commonly due secondarily to infection that can be categorized as acute osteomyelitis login to view 2 more bullets chronic osteomyelitis login to view 2 more bullets Epidemiology risk factors diabetes peripheral vascular disease open fracture intravenous drug use catheter use surgery Etiology note that infection can be due to bacteria, fungi, and mycobacteria microbiology Staphylococcus auerus login to view 6 more bullets Neisseria gonorrhoeae login to view 1 more bullet Staphylococcus epidermidis login to view 1 more bullet Salmonella species login to view 1 more bullet Mycobacterium tuberculosis login to view 1 more bullet Pasteurella multocida login to view 1 more bullet Pseudomonas and Candida login to view 1 more bullet Pathogenesis hematogenous seeding of bone contiguous spread of infection from adjacent structures (e.g., soft tissues and joints) direct inoculation e.g., penetrating trauma and contaminated surgical tools Prognosis mortality has significantly decreased since the use of antibiotics Presentation Symptoms acute osteomyelitis lethargy acute pain in affected site erythema and chronic osteomyelitis chronic pain Physical exam swelling erythema tenderness reduced range of motion bone tenderness ulcers exposed bone may be seen sinus tract pathognomonic for chronic osteomyelitis must perform a neurovascular exam Imaging Radiographs indication preferred initial test in evaluating for osteomyelitis login to view 1 more bullet findings periosteal thickening and elevation "Codman triangle" Magnetic resonance imaging indication considered when radiography is unrevealing findigs may reveal bone necrosis, abscess, and sinus tracts Studies Labs ↑ C-reactive protein ↑ erythrocyte sedimentation rate leukocytosis present in acute osteomyelitis unlikely to be found in chronic osteomyelitis Biopsy and culture confirms the diagnosis Differential Septic arthritis Gout Cellulitis Osteosarcoma Treatment Medical empiric antibiotics indication login to view 2 more bullets Operative debridement indication login to view 1 more bullet Complications Bone necrosis Sepsis Squamous cell carcinoma most common tumor associated with osteomyelitis