Osteomyelitis: Orthopedic High-Yield
Infectious Orthopedics: Diagnostic and Clinical Pearls
1. Pathogen & Patient Associations
| Clinical Context | Most Likely Pathogen |
|---|---|
| General Population (Hematogenous) | Staphylococcus aureus |
| Sickle Cell Disease | Salmonella spp. |
| Diabetic Foot Ulcer | Polymicrobial (Staph, Strep, Gram-negatives, Anaerobes) |
| Prosthetic Joint/Hardware | Staphylococcus epidermidis |
2. Radiographic Progression
- Early (Days): Plain radiographs are usually normal (showing only soft tissue swelling).
- Intermediate (Weeks): Periosteal reaction, cortical bone erosion, and lucent lesions (sequestrum/involucrum) appear.
- Gold Standard Imaging: MRI is the most sensitive and specific modality for early detection of bone marrow edema and abscesses.
3. High-Yield NEET Concepts
- Sequestrum: A piece of dead, devitalized bone that has separated from sound bone during necrosis.
- Involucrum: New bone formation that surrounds the necrotic sequestrum.
- Brodie’s Abscess: A subacute/chronic form of osteomyelitis manifesting as a localized lytic lesion, commonly in the metaphyseal area of long bones.
- Management: Bone biopsy/culture is the “Gold Standard” for diagnosis. Treatment involves surgical debridement and prolonged, targeted IV antibiotic therapy.