1. Diagnosis and treatment of DM foot infections (2012 IDSA Clinical Practice Guidelines) Moon Soo-youn Division of Infectious Diseases Kyung Hee University Hospital at Gangdong

2. Diabetic foot infections (DFI) –Improper diagnosis and therapeutic approaches  amputations Infected diabetic foot or not? –Antibiotics? –Surgical interventions?

6. I.In which diabetic patients with a foot wound should I suspect infection, and how should I classify it? II.How should I assess a diabetic patient presenting with a foot infection? III.When and from whom should I request a consultation for a patient with a diabetic foot infection? IV.Which patients with a diabetic foot infection should I hospitalize, and what criteria should they meet before I discharge them? V.When and how should I obtain specimen(s) for culture from a patient with a diabetic foot wound?

7. VI.How should I initially select, and when should I modify, an antibiotic regimen for a diabetic foot infection? VII.When should I consider imaging studies to evaluate a diabetic foot infection, and which should I select? VIII.How should I diagnose and treat osteomyelitis of the foot in a patient with diabetes? IX.In which patients with a diabetic foot infection should I consider surgical intervention, and what type of procedure may be appropriate? X.What types of wound care techniques and dressings are appropriate for diabetic foot wounds?

8. I. In which diabetic patients with a foot wound should I suspect infection, and how should I classify it?

9. Possibility of infection occurring in any foot wound in a patients with diabetes –Classic signs of inflammation: redness, warmth, swelling, tenderness, or pain –Purulent secretions –Additional or secondary signs: nonpurulent secretions, friable or discolored granulation tissue, undermining of wound edges, foul odor –≥2 of the classic findings of inflammation  infected (2004)

10. Factors increasing the risk for DFI –Positive probe-to-bone (PTB) test –Ulceration >30 days –History of recurrent foot ulcers –Traumatic foot wound –Peripheral vascular disease –Previous lower extremity amputation –Loss of protective sensation –Renal insufficiency –History of walking bare foot

11. Perfusion Extent Depth Infection Sensation

12. Other classification systems –Meggitt-Wagner: ulcer depth, presence of infection and gangrene –S(AD)/SAD: size, (area, depth), sepsis (infection), arteriopathy, and denervation –University of Texas (UT) ulcer classification: combined matrix of 4 grades and 4 stages –Ulcer Severity Index: 20 clinical parameters –Diabetic Ulcer Severity Score (DUSS) and MAID: specific wound characteristics associated with stages of wound repair –DFI Wound Score: semiquantitative assessment of the presence of signs and symptoms of inflammation, combined with measurements of wound size & depth

13. II. How should I assess a diabetic patient presenting with a foot infection?

14. The patient as a whole –Complications of diabetes: peripheral neuropathy, peripheral vascular disease, neuro-osteoarthropathy, impaired wound healing –Various patients comorbidities –Maladaptive behaviors –Immunologic perturbations – reduced PMN function, impaired humoral and cell-mediated immunity The affected foot or limb –Vascular supply: arterial ischemia, venous insufficiency Ankle-Brachial Index –Presence of protective sensation –Biomechanical problems

15. The infected wound –Debride any wound with necrotic tissue or surrounding callus –Microorganisms colonize all wounds  clinical diagnosis!

16. III. When and from whom should I request a consultation for a patient with a diabetic foot infection?

17. Multidisciplinary diabetic foot care team –Endocrinology, dermatology, podiatry, general surgery, vascular surgery, orthopedic surgery, plastic surgery, wound care, psychology or social work –Specialists in infectious diseases or clinical microbiology Ischemia – revascularization –Peripheral arterial disease –ABI <0.40 Pressure off-loading, dressing techniques

18. IV. Which patients with a diabetic foot infection should I hospitalize, and what criteria should they meet before I discharge them?

19. Hospitalization –All patients with a severe infection –Selected patients with a moderate infection with complicating features (sever PAD, lack of home support) –Any patient unable to comply with an appropriate outpatient treatment regimen –Patient failing to improve with OPD therapy Discharge –Clinically stable –Any urgently needed surgery performed –Acceptable glycemic control –Able to manage at discharge location –Well-defined plan including appropriate antibiotic regimen, off-loading scheme, wound care and OPF f/u

20. V. When and how should I obtain specimen(s) for culture from a patient with a diabetic foot wound?

21. Infected wound culture prior to empiric antibiotic therapy

22. VI. How should I initially select, and when should I modify, an antibiotic regimen for a diabetic foot infection?

24. Route of therapy –All severe and some moderate DFIs: IV therapy, at least initially –Most mild, and in many moderate infections: Highly bioavailable oral antibiotics –Selected mild superficial infection: Topical therapy Duration of therapy –Until, but NOT beyond resolution of findings of infections –NOT through complete healing of the wound –1-2 weeks for mild infections –2-3 weeks for moderate to severe infections

25. Gram positive cocci

26. In countries where P. aeruginosa is a frequent isolate In patients who have been soaking their feet In patients who have failed therapy with non-pseudomonal therapy In patients with severe infection History of previous MRSA infection or colonization within the past year Local prevalence of MRSA is high enough (50% for mild and 30% for moderate SSTI) Severe infection – failing to empirical coverage for MRSA  unacceptable risk of treatment failure Most severe Chronic, previously treated, or severe infections

27. VII. When should I consider imaging studies to evaluate a diabetic foot infection, and which should I select?

28. Plain radiographs for all patients with new DFI –Bony abnormality, soft tissue gas and radio-opaque foreign bodies

29. MRI –Study of choice for additional imaging –Soft tissue abscess, osteomyelitis

30. Combination of radionuclide bone scan and a labeled WBC scan –Best alternative when MRI is unavailable or contraindicated

31. VIII. How should I diagnose and treat osteomyelitis of the foot in a patient with diabetes?

32. Diagnosis –PTB test for any DFIs with an open wound –Plain X-ray relatively low sensitivity and specificity Serial X-ray –MRI –Leukocyte or antigranulocyte scan + bone scan –Bone culture and histology  definitive diagnosis

34. Treatment –Microbiology S. aureus, S. epidermidis E. coli, K. pneumoniae, Proteus species, P. aeruginosa Peptostreptococcus, Peptococcus, Finegoldia magna –Surgical treatment or medical treatment?

37. –Adjunctive treatment Hyperbaric oxygen therapy –Cochrane review – reduced risk of major amputation (2004) Growth factors (granulocyte colony stimulating factor) –No accelerated resolution of infection but reduced need for operative procedures (2004) Maggots (larvae) Topical negative pressure therapy (Vacuum-assisted closure) No persuasive evidence

38. IX. In which patients with a diabetic foot infection should I consider surgical intervention, and what type of procedure may be appropriate?

39. Urgent surgical intervention –Gas in the deeper tissues, abscess, necrotizing fasciitis Less urgent surgery –Wounds with substantial nonviable tissue or extensive bone or joint involvement Early, evolving infection –Best to delay surgery in an attempt to avoid the consequent scarring and deformity Key element to any surgical approach –To reach the appropriate foot compartment(s) and extend the exploration and debridement to healthy tissue 4-7 compartments

41. Revascularization –Ischemia secondary to larger-vessel atherosclerosis rather than to “small-vessel disease” –Angioplasty or vascular bypass

42. X. What types of wound care techniques and dressings are appropriate for diabetic foot wounds?

43. Appropriate wound care –Debridement Removing colonizing bacteria Granulation tissue formation and re-epithelialization Reducing pressure at callused sites Collection of appropriate specimens for culture Examination for the presence of deep tissue involvement Relatively contraindicated in wounds primarily ischemic

44. –Redistribution of pressure off the wound to the entire weight-bearing surface of the foot (“off-loading”) Vital part of wound care Total contact cast: often considered “gold standard” device –Caution in patients with severe PAD or active infection Other devices –Removal, especially at home

45. –Wound dressing Optimal healing environment Moist wound environment  granulation, autolytic processes, angiogenesis, more rapid migration of epithelial cells across the wound base Continuously moistened saline gauze: dry/necrotic wounds Hydrogels: dry/necrotic wounds facilitate autolysis Films: occlusive/semi-occlusive, moistening dry wounds Alginates: drying exudative wounds Hydrocolloids: absorbing exudate & facilitate autolysis Foams: exudative wounds

46. –Topical antimicrobials – not advocated Topical antiseptics and silver-based dressings –Little evidence –Expense, potential for local adverse effects –Emergence of bacterial resistance –Adjunctive therapy – no supportive data Hyperbaric oxygen therapy Platelet-derived growth factors G-CSF Bioengineered skin equivalents Topical negative pressure

48. Infection should be suspected in all DM foot –PEDIS grade Treatment –OFF-LOADING –Debridement, dressing –Antibiotics Until infection is controlled, NOT until wound healing –Vascularity - revascularization Osteomyelitis –X-ray, MRI –Longer antibiotics –Surgical treatment

49. Prevention (2004 guidelines) –Detection of neuropathy before its complication ensue –Optimizing glycemic control –Appropriate footwear –Avoiding foot trauma –Daily self-examination of the feet