View source for Diabetic foot infection

==Background==
*75% of patients have polymicrobial infection, usu 70% are [[gram positive]] 
**Severe limb/life threatening infection are more likely to involve [[gram negative]] aerobic &amp; [[anaerobic bacteria]] as well. 
**[[MRSA]] is increasing in frequency
*Ulcer depth is important predictor of healing rate, [[osteomyelitis]] (OM) &amp; risk of amputation. 
*Failure of ulcer to heal by 50% or more after 1 month of treatment is a strong predictor that the ulcer is unlikely to heal after 3 months. 
*Recurrence or amputation is 50-70% over 3-5 yrs. Overall, 50-80% will heal within 6 months with optimal care. 

==Clinical Features==
[[File:PMC2788600 vhrm-5-949f1.png|thumb|Infection in ulcer bed with mild surrounding erythema (''not'' probe-able to bone)]]
[[File:PMC3464072 DFA-3-18693-g011.png|thumb|Classic diabetic plantar ulcer overlying the third metatarsal head with purulent drainage. Ability to probe to bone confirmed osteomyelitis.]]
[[File:Neuropathic heel ulcer diabetic.jpg|thumb|Neuropathic diabetic foot ulcer.]]
*[[Diabetes mellitus]] ulcers usually occur at areas of increased pressure (sole of foot) or friction 
**Venous ulcers usually present above malleoli with irregular borders 
**Arterial ulcers usually found on the toes or shins, with pale, "punched-out" borders (typically painful)
*Often history of minor/unnoticed trauma such as ill-fitting footwear
*Note hair and nail growth, determine vascular status (palpate DP, PT, and popliteal pulse) 
*Probe ulceration site, note involvement of bone, joint, tendon, or sinus tract formation 
**Often more extensive than initially appear
**Use sterile probe, if hit bone chance of OM 90% higher
*+/- systemic symptoms (e.g. [[fever]], malaise)
*50% or more of patients with SEVERE diabetic foot infections will have no systemic signs and symptoms of infection (i.e. fever, tachycardia, leukocytosis, left shift)

*[[Diabetes mellitus]] foot ulcer infection presumed if: 
**2 or more of following: erythema, warmth, tenderness, or swelling 
**OR if pus coming from ulcer site or nearby sinus tract 
*Severe diabetes mellitus foot infection if: 
**Abnormal vital signs 
**Rim of erythema surrounding ulcer or ulcer >2 cm in diameter 
**Lymphangitic streaking or signs of fasciitis (crepitus, skip lesions, severe tenderness, bullae), or if probe reaches bone/joint/tendon

==Differential Diagnosis==
{{Foot infection}}

{{Hyperglycemia DDX}}

==Evaluation==
===Workup===
*Obtain ABI on all patients with: nonpalpable DP/PT, claudication symptoms, ischemic foot pain 
**Consider vascular consult if abnormal: 
***ABI <0.4 (severe obstruction) 
***ABI 0.4-0.69 (mod obstruction)

====Labs====
*Chem 10, CBC, Coags, A1c, consider ESR/CRP (useful for monitoring response to treatment) 
*ESR >40 increased chance of OM 12 fold, an ESR >70 makes diagnosis nearly certain.

====Imaging====
*X-rays to detect soft tissue gas, foreign body, OM, or structural foot deformities 
**OM: x-ray changes occur late in disease, negative xrays do not exclude 
*MRI to eval for OM (not usually done in ED)

===Diagnosis===
*Determine presence/extent of infection and likelihood of OM/fasciitis
*Consider Charcot arthropathy (diabetic neuropathic osteoarthropathy)
**commonly missed diagnosis
**requires different management (total contact cast, NWB)

====Likelihood of Osteomyelitis====
*Factors that increase likelihood of osteomyelitis: 
**Visible bone or probe to bone 
**Ulcer >2cm in size 
**ESR >70 
**Ulcer duration >2 weeks

==Management==
===Non-infected chronic wounds<ref name="IDSA">2012 Infectious Diseases Society of America Clinical Practice Guideline for the Diagnosis and Treatment of Diabetic Foot Infections [http://www.idsociety.org/uploadedFiles/IDSA/Guidelines-Patient_Care/PDF_Library/2012%20Diabetic%20Foot%20Infections%20Guideline.pdf full text]</ref>===
*Prophylactic antibiotics not indicated 
*For clinically uninfected wounds, do not collect a specimen for culture
*Moist dressing to allow for healing and proper footwear to prevent worsening abrasions

===Infected Wounds<ref name="IDSA"></ref>===
*Consider wound culture prior to starting empiric antibiotic therapy. However cultures may be unnecessary for a mild infection in a patients who have not recently received antibiotic therapy.
*Coverage is targeted at [[MSSA]] + [[Streptococcus Genus|Strep]])
*Strict non-weight bearing, tight glycemic control, meticulous wound care

===Severe infection<ref name="IDSA"></ref>===
*Admit with surgical consult
*Empiric therapy directed at [[Pseudomonas aeruginosa]] is NOT necessary except for patients with risk factors for true infection with this organism
*[[MRSA]] coverage in a patient with a prior history of MRSA infection

===[[Antibiotics]]===
{{Diabetic foot infection antibiotics}}

==Disposition==
*Non-infected chronic wounds: outpatient management
*Infected Wounds: Low threshold for admission vs. outpatient management with antibiotics
*Severe infection: Admit with surgical consult

==See Also==
*[[Foot diagnoses]]
*[[Osteomyelitis]]
*[[Neuropathic pain]]
*[[Wound care dressing basics]]

==External Links==


==References==
<references/>

[[Category:ID]] 
[[Category:Endocrinology]]