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Diabetic Foot Osteomyelitis — RACP Adult Medicine MCQ

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ModerateInfectious DiseasesDiabetic Foot OsteomyelitisRACP Adult Medicine

A 60-year-old man with poorly controlled type 2 diabetes presents with a red, hot, swollen right foot. He stood on a nail 5 days ago. There is a deep ulcer on the plantar surface with probing to bone. X-ray shows periosteal reaction and cortical destruction of the second metatarsal. What is the most likely diagnosis?

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Correct answer: E — Osteomyelitis

Probe-to-bone test positivity in a diabetic foot ulcer has >85% positive predictive value for osteomyelitis. X-ray changes (periosteal reaction, cortical destruction) confirm the diagnosis. MRI is more sensitive for early detection. Treatment requires prolonged antibiotics (typically 6 weeks) and often surgical debridement.

Reference: eTG Antibiotic – 2025 – Diabetic Foot Infection; Lipsky 2020 IWGDF Guidelines