Guidelines
Diabetic Foot Infection

Diabetic Foot Infection

Diagnosis

Diabetic patient with foot ulcer

AND

Two or more of:

  • redness
  • warmth
  • swelling or induration
  • pain or tenderness
  • purulent discharge
  • HgbA1c (if result not available from past 3 months)
  • CRP (if exposed bone/concern for osteomyelitis)
  • Deep tissue specimen, bone specimen, or aspirate of purulent fluid sent for C&S (aerobic and anaerobic)
  • Plain xray of the affected area on admission
  • Ankle-brachial index (ABI)

Classification of Severity

  • Local infection involving epidermis and subcutaneous tissue
  • Signs of inflammation (erythema, warmth, tenderness) limited to within 2 cm of wound margin
  • No systemic symptoms or signs
  • Infection involving tissue deeper than epidermis and subcutaneous tissue
  • Signs of inflammation (erythema, warmth, tenderness) may extend beyond 2 cm 
  • Absence of systemic signs of SIRS
  • Local foot wound infection with signs of systemic inflammatory response syndrome (SIRS)
  • SIRS = presence of >2 of the following signs:
    • Temp >38°C or <36°C
    • Heart rate >90 beats/min
    • Respiratory rate >20 breaths/min
    • PaCO2 <32 mm Hg
    • WBC count >12 or <4, or >10% bands
  • Hypotension
  • Metabolic disturbance (severe hyperglycemia, new onset renal insufficiency)

Antibiotic Treatment According to Severity

Additional Management

Optimize glycemic control

  • Antimicrobial absorbent dressing
  • Consult Wound Care Team
  • Consult general surgery if necrotic tissue present
  • Assessment for peripheral arterial disease warranted for every diabetic patient with foot ulcer
  • Ankle-brachial index (ABI) (<0.9 is abnormal)
  • CT peripheral angiography with run-offs if/once renal function is optimized
  • Consult vascular surgery (phone call) with CT angio results
  • Suspect this when bone is visualized, palpated, or wound probes to bone
  • MRI is most sensitive and specific imaging modality
  • Bone scan helpful if negative; positive result needs confirmation with gallium scan
  • Gallium scan used when MRI is not available or contraindicated
  • Decisions regarding anticoagulant thromboprophylaxis in acutely ill, hospitalized medical patients should be made after consideration of risk factors for both VTE and bleeding
  • For more information, refer to Thrombosis Canada Clinical Guides
  • Higher doses of prophylactic LMWH indicated for weight >120 kg

Note: High VTE Risk population = Active cancer, obesity, history of VTE

  • A multidisciplinary approach for the treatment of ulcers has been shown to improve outcomes
  • The team may include:
    • wound care nurses
    • vascular surgery
    • orthopedic surgery
    • plastic surgery
    • infectious disease consultant
    • internal medicine
    • physiatry
    • orthotists
    • diabetes educators

References