Diabetic Foot Infection: A challenge for primary and secondary care

1. Diabetic Foot Infection: A challenge for primary and secondary care? Dr Tony Berendt Consultant Physician Bone Infection Unit NOC NHS Trust, Oxford

2. Disclosure of Potential Conflicts of Interest Has received honoraria, travel expenses and hospitality for serving on speakers bureaux and advisory boards for RPR (Synercid), Pfizer (Linezolid) MSD (Ertapenem) and MacroChem (Pexiganin) Vice-Chair of IDSA Clinical Practice Guidelines Committee for Diabetic Foot Infections; Chair of IWGDF Osteomyelitis Sub-group Member of Oxfordshire Priorities Forum and ORH-NOC Medicines Advisory Committee DIPC at NOC, Chair of TV (South Central) CHAIN and Steering Group for pan-Oxfordshire C. difficile intervention project

3. Infection and Healing

4. Learning objectives Be able to discuss the epidemiological importance of DFI Know how to assess risk of diabetic foot ulceration and infection Be able to assess a patient with a diabetic foot infection, in the context of published guidelines, and make rational antibiotic choices

5. General epidemiology 252 million diabetics worldwide

7. General epidemiology 252 million diabetics worldwide Foot problems account for largest number of hospital bed days used for diabetic patients 1-4% of diabetics develop foot ulcer annually, 25% in lifetime 45-75% of all lower extremity amputations are in diabetics 85% of these preceded by foot ulcer Two-thirds of elderly patients undergoing amputation do not return to independent life Studies have shown less costs for saving a limb cf. amputation

8. Pathophysiology: diabetic foot ulceration Neuropathy

10. Pathophysiology: diabetic foot ulceration Neuropathy

11. 30-second foot examination Any previous diabetes related foot problems? Are both foot pulses palpable? Is protective sensation intact? Is there evidence of significant foot deformity?

13. Two-minute foot examination Examine feet for ulcers, callus, blisters, maceration, skin breaks, infection Examine the toenails Identify nature of any foot deformity Examine the shoes Observe patient�s ability to perform foot care and examination (by observing them replace socks and shoes) Establish need for patient education

14. Standard ulcer care Evaluate for infection Debride ulcer, remove callosities Check for sensation (monofilament) Check for circulation (pulses, Dopplers) Probe to bone? Adequate offloading Antibiotics if infected Secondary prevention of ulcer and of major diabetes related events

15. Overview of Diabetic Foot Infections

16. Independent Risk Factors* for Foot Infection:Diabetex Prospective Trial Variable Risk Ratio (95%CI) p Value Wound depth to bone 6.7 (2.3�19.9) 0.001 Wound duration >30 days 4.7 (1.6�13.4) 0.004 Recurrent foot wound 2.4 (1.3�4.5) 0.006 Traumatic wound etiology 2.4 (1.1�5.0) 0.02 Peripheral vascular disease 1.9 (1.0�3.6) 0.04

17. Microbiology Popular mythology = all infections are polymicrobial

19. Treatment: myths Treat uninfected ulcers to promote healing Treat infected ulcers until the ulcer is healed Treat all the organisms isolated from the microbiological specimens Hospitalise all infections Give lots of intravenous therapy

20. Timeline of Staphylococcal antibiotic resistance

22.

24. Evaluating the Patient with a DFI Patient Systemic response Fever, chills, sweats, cardiovascular status Metabolic status Hyperglycaemia, electrolyte imbalance, hyperosmolality, renal impairment Cognitive function Delirium, depression, dementia, psychosis Social situation Support, self-neglect � Limb/Foot � Wound

25. Evaluating the Patient with a DFI Patient Limb or Foot Biomechanics Vascular Ischaemia Venous insufficiency Neuropathy Infection Wound Size, depth Necrosis, gangrene Infection

27. Clinical Classification of Diabetic Foot Infection Wound without purulence or other evidence of inflammation ?More than 2 of purulence, erythema, pain, tenderness, warmth or induration. Any cellulitis/erythema extends =2 cm around ulcer and infection is limited to skin/superficial subcut tissues. No local complications or systemic illness Infection in patient who is systemically well & metabolically stable but has any of: cellulitis extending >2 cm; lymphangitis; spread beneath fascia; deep tissue abscess; gangrene; muscle, tendon, joint or bone involved Infection in a patient with systemic toxicity or metabolic instability

28. Outcomes By IDSA DFI Severity Classification

32. Table 8: Suggested Antibiotic Regimens: DFI

35. The diabetic foot: Charcot foot with �rocker bottom� deformity

36. Charcot foot grossly disordered architecture and biomechanics midfoot ulceration instability of midfoot note previous minor amputations still well-vascularised

37. Bone resorption and destruction

38. Bone regeneration on antibiotic therapy

39. Conclusions Ulceration is a common consequence of diabetic neuropathy To understand and treat ulceration, understand the pathophysiology and biomechanics Infection (DFI) is a common and frequently serious consequence of diabetic foot ulceration (DFU) A structured approach to assessment and treatment, using international or local guidelines, provides a means to rationalise care and improve outcomes Care must be multidisciplinary to achieve this; agreed pathways, health service management and audit are required