Synopsis
Detect bone infection beneath a neuropathic ulcer without relying on one negative test, grade systemic and limb threat, obtain useful tissue, restore perfusion and pressure control, and choose medical or surgical treatment coherently.
- Think osteomyelitis when diabetes accompanies local infection, a deep wound or a chronic ulcer; absence of pain is expected in neuropathy and never reassures.
- Normal CRP, plain radiographs or probe-to-bone testing do not individually exclude diabetic-foot osteomyelitis under NICE NG19.
- Grade the whole threat: systemic severity, depth and extent, abscess or necrosis, perfusion, neuropathy, glucose and ketones, renal function and ability to offload.
- Initial imaging is plain radiography. If osteomyelitis remains suspected but unconfirmed, NICE advises considering MRI to confirm and map disease.
- Obtain a deep tissue specimen after cleansing and debridement; bone culture and histology are most specific when the diagnosis or pathogen remains uncertain. Avoid treating a surface swab as bone microbiology.
- Drain abscess and excise non-viable tissue promptly. Coordinate revascularisation and debridement when ischaemia threatens healing rather than assuming either can safely wait in every case.
- For moderate or severe infection, NICE lists oral treatment first-line when feasible, intravenous treatment for severe illness for at least 48 hours until stabilised, and intravenous review at 48 hours.
- Course length is based on response and source control: NICE allows a minimum of 7 days and up to 6 weeks for osteomyelitis, using oral therapy for prolonged treatment when possible.
Key red flags
Systemic inflammatory response, confusion, hypotension, tachypnoea, lactate elevation or metabolic decompensation defines severe infection and requires hospital sepsis care rather than ambulatory wound treatment.
Crepitus, bullae, skin anaesthesia, rapidly spreading discoloration or pain beyond visible change raises concern for necrotising infection and demands immediate surgical exploration.
Coldness, rest pain, absent Doppler signals, gangrene or a non-healing wound with poor perfusion requires urgent vascular assessment; neuropathy can make limb-threatening ischaemia painless.
Deep fluctuance, purulent tracking, exposed bone, new deformity or an unstable hot swollen foot suggests abscess, osteomyelitis, septic joint or acute Charcot change and needs multidisciplinary imaging and offloading.
Investigation priorities
Assess bone destruction, gas, foreign body and deformity.
Management branches
Systemic inflammatory response, metabolic decompensation, necrosis or rapidly advancing deep infection is present.
- Admit, apply sepsis care, obtain blood cultures and begin severity-appropriate intravenous antibiotics immediately.
- Call foot, orthopaedic or vascular surgery urgently and drain abscess or remove necrotic tissue without waiting for perfect imaging.
- Assess arterial supply and coordinate revascularisation around immediate source-control needs.
- Control glucose and ketones, protect renal function and completely offload the affected foot.
A deep ulcer suggests osteomyelitis without systemic instability or immediate necrosis.
- Clean and debride the wound, document probe-to-bone, perfusion, neuropathy and mechanical loading.
- Obtain blood tests and initial radiographs, then use MRI when suspicion remains but radiography is non-confirmatory.
- Secure deep tissue or planned bone culture and histology when the result will change prolonged therapy or surgery.
- Choose oral treatment first-line when severity and absorption permit, linked to offloading, wound and vascular plans.