DIABETIC FOOT ULCERS AND INFECTION: IT S NOT WHAT YOU PUT ON AN ULCER THAT HEALS AN ULCER. IT S WHAT YOU TAKE OFF

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1 DIABETIC FOOT ULCERS AND INFECTION: IT S NOT WHAT YOU PUT ON AN ULCER THAT HEALS AN ULCER. IT S WHAT YOU TAKE OFF Dr Bill Thompson Associate Professor of Medicine Schulich School of Medicien and Dentistry Western University October, 28, 2016 OBJECTIVES To understand the changes in the feet of diabetics that lead to foot ulceration To be able to identify a foot at risk To be able to manage an infected or non infected foot ulcer Initial evaluation General principles Who do you ask for help? 1

2 THESE FEET WERE MADE FOR WALKING THE DIABETIC FOOT AND NEUROPATHY The diabetic foot is prone to ulceration from neuropathy because of Loss of sensation Loss of motor power Development of abnormal blood flow All of the above None of the above 2

3 NEUROPATHY ASSESSMENT MONOFILAMENT TEST NORMAL FOOT STRUCTURE UGisEC_9IZU/T01gA3ObHRI/AAAAAAAAAS8/I1a 8b3FY_LY/s1600/foot-muscles.jpg 3

4 MRI OF FOOT 4

5 5

6 WHAT IS THE COMMON FEATURE FOR THESE ITEMS? 6

7 OTHER SHOE RELATED INJURY Slip sliding away Bad wear pattern Narrow shoe with inadequate toe box No real protection here but most common in house foot wear IF THE SHOE DOESN T FIT 7

8 PROGRESSION OF A FOOT ULCER MARCH 20,2016 PROGRESSION OF A FOOT ULCER APRIL 11 JUNE 29 SEPT 19 8

9 WHY THE DIABETIC FOOT GETS INFECTED Neuropathy sensation Motor weakness Deformity Trauma Compressive Shear stress Shoes (50%) Environmental Ulcer Infected ulcer Bacteria colonize & invade Vasculopathy proximal distal Impaired Cell Function glucose neutrophils ANATOMIC LOCATIONS AND TYPES OF ULCERS In the following slides consider which of the ulcers are infected and whether you would give antibiotics 9

10 ANATOMIC LOCATIONS AND TYPES OF ULCERS Paronychia Dropped metatarsal heads and damaged 1 st MTH Rocker bottom Charcot foot ulcer Hammer toe ulcer ANATOMIC LOCATIONS AND TYPES OF ULCERS Time heals all wounds In the diabetic foot. Time wounds all heels 10

11 ANATOMIC LOCATIONS AND TYPES OF ULCERS Stiff MTP joint (Hallux rigididis) INFECTION 50% of DFUs become infected during management (Lipsky BA, et al. 2006) 90% amputations preceded by infection (Pecoraro RE et al, 1990) Diagnosis Based on clinical symptoms and signs. No diagnostic test available to diagnose infection. Other tests used to guide clinical treatment NOT to help diagnose Lipsky, B. A., Berendt, A. R., Deery, H. G., Embil, J. M., Joseph, W. S., Karchmer, A. W., et al. (2006). Diagnosis and treatment of diabetic foot infections. Plastic and Reconstructive Surgery, 117(7 Suppl), 212S-238S. 11

12 DIAGNOSING INFECTION Infection should be diagnosed clinically on the basis of the presence of at least 2 of the cardinal manifestations of inflammation Purulent exudate, redness, warmth, swelling or induration, and pain or tenderness Lipsky B, et al, 2012, 2012 Infectious Diseases Society of America Clinical Practice Guideline for the Diagnosis and Treatment of Diabetic Foot Infections FOOT ULCER AND INFECTION IN DM Factors promoting infection include: type, depth, and location of the ulcer; tissue perfusion; and the integrity of the host immune response. Impaired sensory nerve function (neuropathy) delayed and attenuated inflammatory response Not dysfunction of microvasculature, rather dysfunction of response to tissue damage Therefore, signs & symptoms of infection are reduced in 1/2 PWD may just be in pain or exudate or size or smell difficult to judge Other signs may indicate infection.. 12

13 SEVERE INFECTION 50% of patients with a limb-threatening infection do not manifest systemic signs or symptoms Requires immediate hospital admission and surgical intervention Life / limb threatening This patient presented to emerg after having the ulcer for three months. She was wrapping it with facial tissues. She removed the proximal phalanx when the bone poked through the ulcer MICROBIOLOGY OF DIABETIC FOOT INFECTIONS Most infections are polymicrobial Aerobic Gm + cocci (S. aureus, B-hemolytic Streptococci) most common Aerobic gram negatives important co-pathogens in chronic wounds or after antibiotics Anaerobes co-pathogens in ischaemic or necrotic wounds 13

14 ASSESSMENT OF THE DIABETIC PATIENT S FOOT FOR RISK OF/OR ULCERATION NEUROPATHY ASSESSMENT MONOFILAMENT TEST 14

15 VASCULAR ASSESSMENT ANKLE BRACHIAL INDEX IDSA Interpretation of ABI s >1.3: Poorly compressible arteries, vascular calcification : Normal : Mild arterial obstruction Moderate arterial obstruction < 0.4: Severe arterial obstruction ABI < 0.6 indicates poor healing potential ASSESSMENT OF FOOT TEMPERATURE Infrared laser thermometer Uses A difference of 2 o C or 5 o F is suggestive of infection when compared to same site other foot all other factors being equal Useful in monitoring activity of acute charcot foot Development of temperature difference shows an increased risk for the development of a foot ulcer 15

16 WOUND SWAB Effective in antibiotic naïve wounds Swabs less able to identify pathogenic organisms in wounds with: a longer wound history, or recurrent wound and In those patients who have been treated in hospital Guidelines recommend prescribing antibiotics empirically in antibiotic naïve wounds Is it really necessary to do a swab, when realistically, we know what the treatment will be anyway? Culturing prior to antibiotics if admitted to hospital benificial However: In certain circumstances swabs may be the only available method Better than nothing LEVINE S TECHNIQUE Gently debride and clean the wound Can use normal saline to wash Avoid swabbing undebrided ulcers or wound drainage. use a swab designed for culturing aerobic and anaerobic organisms Select area near center of wound, free of necrosis and debris Rotate swab over 1 cm 2 area for 5 seconds applying pressure to extract fluid (90% sensitivity & 57% specificity) Need to transport specimens to the laboratory: promptly, and in suitable transport media. Gardner et al (2006) Lipsky et al (2006) 16

17 WOUND BED TISSUE SCRAPING Wound swabs poorly correlated to pathogenic organisms in these cases Swabs take the superficial organisms wound contains many organisms unlikely to capture the actual infective organism Wound bed tissue scrapings more sensitive Used to identify pathogenic organisms NOT to diagnose infection Clinical signs and symptoms used to diagnose Lipsky B et al (2006) How to take a specimen? Before obtaining specimens for culture Cleanse and debride the lesion Obtain tissue specimens from debrided base by: curettage (scraping with sterile dermal curette or scalpel blade), (Level of evidence A-I), or biopsy (bedside or operative) (Level of evidence A-I). Clearly identify samples specimen type and anatomic location Promptly send them to the laboratory for aerobic and anaerobic culture in an appropriate sterile container or transport media 17

18 TAKING THE PRESSURE OFF Antibiotics covering Staph and Strep, gram negatives Keflex Clavulin Levofloxacin If concerned about anaerobes add metronidazole or use clavulin In dialysis patient culture if possible as higher risk for resistant gram negatives or MRSA DRESSINGS Goal is to keep surface of wound with about the same moisture content as the surface of your eye Any antibacterial dressing is as good as another provided the pressure is taken off the wound and the dressing is changed often enough to keep the moisture level appropriate 18

19 OFF LOADING OPTIONS Silicone rubber buttress for toe ulcers OFF LOADING OPTIONS Hapla felt to foot Sequential layers of 10mm compressed felt Applied directly to foot Aperature left over wound to allow for dressing changes. Tape closes aperature. Patient off loaded. Can t cheat Felt compresses over time and needs to be replaced every 2-3 weeks Felt donuts used for toes and heels Technique not covered by medicare 19

20 OFF LOADING OPTIONS Darco Post op Boot Rocker bottom for gradual transition of pressure Soft and adjustable upper to avoid pressure on wounds Cheaper than a full orthotic and shoe Can apply felt inside Darco or on foot Not durable in the long term but good transition option INFECTED DIABETIC FOOT ULCER 20

21 AIRCAST WALKER PATIENT OUTCOMES FROM ORIGINAL STUDY Study enrolled 83 patients between January 2 and October 31, Patient Demographics 90% Type 2 diabetics Duration of ulcer at baseline /- 2.7 weeks /- 0.41cm sq. and 0.65 =/ deep 114 ulcers at baseline 78 (68%) healed within the study 7.4 weeks to heal over 3.8 clinic visits all ulcers combined (Literature reports time to healing between 11 to 14 weeks in specialist diabetic foot clinics. Neuroischaemic longer than neuropathic) 22 recurrent ulcers (19%) (literature reports relapse rate of 30%) 82% healed (recurrence size smaller) 32 new ulcers. 55% healed 46 patients (55%) ulcer free at end of study 21

22 WHERE WE ARE TODAY (2015 STATS) 257 inactive patients since active patients 25 pending consults Longer wait time to get in More infections Relapses more common International wound Journal, Dubsky et al Risk factors for recurrence diabetic foot ulcers. 57.5% relapse rate after 3 years. Independent risk factors included plantar location, bone infection, poor diabetes control, elevated CRP Some remarkable healing times for chronic ulcers with offloading (less than 6 weeks for ulcers with duration 1-2 years) Recent bad outcomes with infected Charcot feet..more CROW walkers? Charcot Restraint Orthotic Walker WHERE CAN YOU FIND US? London Diabetic Foot Clinic: 310 Wellington St. London Ontario Consults through Dr. Thompson s office at SJHC Fax Clinic Phone Number