A 61 yo F w/ a history of schizophrenia presents to the ED w/R middle finger pain. She reports pain and swelling to that digit for 6 months, but both have worsened over the last 2 days and now there is associated redness. An x-ray is obtained. What's the diagnosis?  (scroll down for answer)

Answer: Osteomyelitis of R third digit

• Most cases of osteomyelitits present via contiguous (~80%) or hematogenous (~20%) spread
• Occurs w/ co-existing septic arthritis in ~15% cases
• Risk factors include: diabetes, IV drug use, sickle cell diease, recent surgery, bite wounds or extremes of age (pediatrics/elderly)
• Plain films may be normal early in course, but later will show periosteal elevation, bone demineralization and lytic lesions
• MRI is 95% sensitive
• Bone biopsy provides definitive diagnosis
• Empiric antibiotic coverage should cover for s.aureus (most common causative agent)
• If patient nontoxic, can discuss with consultant holding antibiotics until culture/biopsy obtained