DIABETIC FOOT INFECTION ISABELLE TREPICCIONE, MD OUTLINE Scope of problem Predisposition Prevention Diagnosis Treatment SCOPE OF THE PROBLEM

Lifetime incidence of foot ulcer is 25% 50% are infected 50% of non-traumatic lower extremity are due to DFI 131 million diabetics worldwide in 2000 366 million diabetics by 2030 COST OF THE PROBLEM Mean annual cost of treatment in 2001: $9,000 for an uninfected foot ulcer $25,000 for an infected foot ulcer $45,000 for a foot ulcer with PREDISPOSING FACTORS

NEUROPATHY VASCULAR DISEASE

IMMUNE NEUROPATHY VASCULAR DISEASE DYSFUNCTION

IMMUNE DYSFUNCTION https://queensnassaupodiatry.com/wp-content/uploads/2013/09/133642406_NerveCell.jp https://vitalplan.com/wp-content/uploads/2016/03/clogged_blood_vessel.jpg Http://yaletownnaturopathic.com/wp-content/uploads/2015/10/immune-system-booster-best-vancouver-naturopatgh.jpeg NEUROPATHY

Sensory neuropathy: Wounds go undetected and worsen with exposure to repetitive trauma Autonomic neuropathy: Gland dysfunction makes skin dry and susceptible to tearing Motor neuropathy: Atrophy of intrinsic foot muscles leads to anatomic deformities

http://img.webmd.boots.com/dtmcms/live/webmd_uk/consumer_assets/site_images/articles/health_tools/common_foot_problems/PRinc_rm_photo_of_hammer_toes.jpg http://img.medscapestatic.com/pi/features/slideshow-slide/charcot-foot/fig13.jpg?resize=645:439 VASCULAR DISEASE Hyperglycemia causes endothelial cell dysfunction and smooth muscle cell abnormalities Hyperglycemia is associated with an increase in thromboxane A2 contributing to hypercoagulability Co-existing hypertension and hyperlipidemia IMMUNE DYSFUNCTION Fewer inflammatory cytokines Impaired neutrophil chemotaxis Impaired neutrophil phagocytosis

http://physrev.physiology.org/content/physrev/83/2/475/F26.large.jpg IDENTIFYING THOSE AT RISK

Hemoglobin a1c >9% (OR 3.2) >10 years with (OR 3.0) Prior lower extremity (RR 2.8) Visual acuity less than 20/40 (RR 1.9) Prior foot ulceration (RR 1.6) PREVENTION

Patient education: Improvement in patient knowledge and behavior. No ulcer or amputation prevention. Yearly screening foot exam: Decreased ulcer recurrence at 1 year if referred to podiatry. No reduction in amputation. Diabetic footwear: Custom footwear prevents ulcer recurrence. Optimize glycemic control: Improves neuropathy. Nonsignificant reduction in amputation. Smoking cessation: Nonsmoking diabetics have lower rates of foot ulceration and amputation. Not studied: Callus debridement, treatment of tinea pedis or onychomycosis, and lower extremity revascularization. Infection indicated by presence of 2 or more of:  Swelling or induration  Erythema  Tenderness  Warmth  Purulent discharge

Lavery LA, Armstrong DG, Murdoch DP, Peters EJ, Lipsky BA. (2007). Validation of the Infectious Diseases Society of America’s diabetic foot classification system. Clin Infect Dis UNINFECTED MILD INFECTION MODERATE SEVERE INFECTION -Local infection INFECTION -Local infection confined to skin -Local infection plus systemic and subcutaneous with involvement inflammatory tissue of deeper response -Circumference of structures syndrome erythema >0.5cm -Circumference of and <2cm erythema >2cm

http://www.aafp.org/afp/2008/0701/p71.html https://www.drugs.com/health-guide/images/205064.jpg http://www.apcofamerica.com/wp-content/uploads/2015/11/diabetic-foot-infection.jpg https://d2v9y0dukr6mq2.cloudfront.net/video/thumbnail/SImAn91gin31gtxk/icu-screen-monitoring-dying-patient-vital-signs-dropping-clinical-death_h7xw2pd0_thumbnail-small01.jpg IDENTIFYING INFECTED ULCERS

Probe to bone, RR 6.7 Ulceration present >30 days, RR 4.7 History of recurrent ulcers, RR 2.4 Traumatic foot wound, RR 2.4 Presence of vascular disease in same limb, RR 1.9

http://www.antimicrobe.org/printout/e26printout/e26assessment.htm WOUND CULTURE

INDICATIONS TECHNIQUE

Culture and gram stain moderate to severely Clean and debride wound infected wounds Obtain culture specimen from base Consider culture of mild infection if there are MRSA or pseudomonas risk factors Aspirate purulence if present Don’t culture uninfected wounds Do not send superficial swabs or swabs of wound drainage

f wound or wound drainage for culture

http://lermagazine.com/wp-content/uploads/2012/10/10diabetes-CG-debride-30.jpg IMAGING Xrays of all new diabetic foot infections MRI if there is concern for other deep space infection MRI when a chronic ulceration becomes infected

http://learningradiology.com/images/boneimages1/osteomyelitisarr.jpg TREATMENT OF THE INFECTED ULCER Antibiotics Wound care Sometimes surgery Does anything else make a difference? ANTIBIOTICS MILD infection: target gram positive cocci, maybe MRSA (ORAL) MODERATE infection: target gram positive cocci, maybe MRSA (ORAL) SEVERE infection: target gram positive cocci, gram negative and obligate anaerobes, MRSA and pseudomonas (PARENTERAL) WHEN DO I NEED TO COVER FOR MRSA? When the patient has a history of MRSA or MRSA colonization within the past year When the infection is severe When local MRSA prevalence is 50% (for mild) or 30% (for moderate) WHEN DO I NEED TO COVER FOR MRSA?

DO NOT ROUTINELY 25% MRSA NEED TO COVER (UNLESS SEVERE)

COVER IN 40% MRSA MODERATE AND SEVERE INFECTION WHEN DO I NEED TO COVER FOR PSEUDOMONAS? Not as common a pathogen in DFI as previously thought Increasing evidence that it may be a wound colonizer The IDSA recommends coverage in: Severe infections Tropical climates Frequent exposure of the foot to water WOUND CARE

Moist wound No topical Debridement Off-loading environment antimicrobials

http://woundcarecenternyc.com/wp-content/uploads/2014/05/BestWoundCareNYC11.jpg http://www.podiatrytoday.com/files/imagecache/normal/FitzgeraldBlog1.png http://www.thegeminigeek.com/wp-content/uploads/2009/12/What-is-the-source-of-moisture-in-the-air.jpeg http://www.microbiologynutsandbolts.co.uk/uploads/7/8/9/4/7894682/1435694724.png WHEN SHOULD I CONSULT A SURGEON? Evidence of life or limb threatening infection Evidence of critical ischemia Evidence of deep-space infection or abscess Failure to improve with otherwise appropriate treatment OTHER TREATMENTS

Negative-pressure wound therapy AKA wound vac Hyperbaric oxygen Granulocyte colony stimulating factors (G-CSF) Stem cell Not studied: intensive glycemic control  limb revascularization

http://m3.i.pbase.com/o6/12/421212/1/101374523.kIMZ12if.wrecked_foot_vacuum_dressin.jpg LEARNING POINTS

When it comes to prevention; focus on appropriate footwear, a1c control, and smoking cessation Send a tissue culture in all but mild diabetic foot infections Most mild and moderate infections do not require MRSA or pseudomonas coverage Wound care is critical to complete healing Call a podiatrist or orthopedic surgeon when the infection is deep or severe QUESTIONS?

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