Diabetic foot resident survival guide

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Diabetic foot Resident Survival Guide Microchapters
Overview
Causes
Diagnosis
Treatment
Do's
Don'ts

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ifrah Fatima, M.B.B.S[2]

Synonyms and Keywords: Diabetic feet; Diabetic ulcer; Diabetic foot infection; Diabetic foot ulcer

Overview

Diabetic foot is a complication of long-standing and poorly controlled diabetes mellitus. Poor glycemic control, peripheral neuropathy, improper footwear, ischemia and possible foot deformities including charcot arthropathy are the main known causes of diabetic foot. A detailed history of the patient's diabetes status, foot care, deformities, foot hygiene, symptoms of ischemia, and history of smoking is necessary to classify the wound or ulcer and treat the underlying cause. Physical examination includes an assessment of the ulcer and tests to detect the severity of peripheral neuropathy (such as Semmes-Weinstein monofilament test) and ischemia (such as Ankle-Brachial Index (ABI)). Routine laboratory investigations are recommended, such as HbA1c. If an infection is suspected, a wound culture is necessary to guide antibiotic therapy. Mechanical offloading such as cast walkers, total contact casting or therapeutic shoes, and podiatric care are essential. Surgical interventions, such as revascularization surgery) may be considered for patient's with ischemia. Antibiotic therapy is based on culture, risk of MRSA infection, risk of pseudomonas infection, presence or absence of complications, such as osteomyelitis and history of recent antibiotic use. Hyperbaric oxygen therapy is considered for a diabetic foot that persists despite treatment for more than 30 days.

Causes

Life Threatening Causes

Life-threatening causes include conditions that may result in death or permanent disability within 24 hours if left untreated. Diabetic foot superseded with the following may result in sepsis and death.[1]

Common Causes

Diagnosis

Assessment of diabetic foot includes evaluation of peripheral arterial disease, peripheral neuropathy, and foot deformities. Shown below is an algorithm summarizing the diagnosis of diabetic foot and diabetic foot ulcers according to the recommendations of the American Diabetes Association and International Diabetes Federation- Clinical Practice Recommendations on the Diabetic Foot 2017. [3][1]

 
 
 
Characterize the symptoms:
❑ Onset
❑ Type of sensation
❑ Location
❑ Nocturnal variation
❑ Aggravating factors
❑ Relieving factors

Obtain a detailed history:
❑ Onset of diabetes
❑ Duration of diabetes
❑ Compliance with medication
❑ History of glycemic control
❑ History of other diabetic complications
❑ Foot deformities/injuries/ulcers
❑ History of lower limb amputation
❑ Type of footwear
❑ Foot hygiene
❑ History of claudication
Smoking history
 
 
 
 
 
 
 
 
 
 
 
 
Examine the patient:
Inspection
❑ Location of ulcer
❑ Integrity and charcteristic (dry/cracked) of skin
Sweating
Palpation
❑ Pedal (dorsalis pedis) pulses
❑ Vibration sensation
❑ Ulcer site- warmth, tenderness, edema
Non-invasive tests
❑ Semmes-Weinstein monofilament test
❑ Probe-to-bone test if suspected osteomyelitis
❑ Measure ABI (Ankle-Brachial Index) with a Arterial doppler
 
 
 
 
 
 
 
 
 
 
 
 
Order tests:
Glycosylated hemoglobin/ HbA1c
Fasting plasma glucose
Complete blood count
ESR and CRP
❑ Deep tissue specimen for culture
 

Treatment

Assessment of diabetic foot includes evaluation of peripheral arterial disease, peripheral neuropathy, and foot deformities. Shown below is an algorithm summarizing the diagnosis of diabetic foot and diabetic foot ulcers according to the recommendations of the American Diabetes Association and International Diabetes Federation- Clinical Practice Recommendations on the Diabetic Foot 2017. [4] [5] [6] [1]

Adapted from Diabetes Care. 2013;36(9):2862-71. and Clin Infect Dis. 2012;54(12):e132-73. [7] [8]

 
 
 
 
 
 
 
 
 
 
Prophylactic measures and Diabetic foot care in all patients
❑ Glycemic control
❑ Apporpriate footwear and podiatric care
• ❑ Mechanical offloading
• Cast Walkers
• Total contact casting
• Therapeutic shoes
❑ Vascular care to prevent and treat peripheral arterial disease
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ Local wound care
❑ Debridement - Mechanical or chemical
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Peripheral arterial disease or signs of ischemia
 
 
Medication/Surgical or endovascular revascularization
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Presence of infection
 
 
• Mechanical or chemical wound debridement
• Culture • Biopsy
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
• Assess severity of infection according to the table below
• Treat with antiobiotics according to the table below
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
If infection does not resolve within 30 days-
• Consider hyperbaric oxygen therapy
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
• Observe foot
• Establish regular care
• Reassess in 2-3 months
 
 
  • DFI is classified based on its severity according to the Infectious Diseases Society of America (IDSA) guideline or the PEDIS grade developed by the International Working Group on the Diabetic Foot (IWGDF). (see Table below)
  • Selection of an empiric antimicrobial regimen should be determined by the severity of DFI and the likely etiologic agents.
Clinical Manifestation PEDIS Grade IDSA Severity
Wound lacking purulence or any manifestations of inflammation 1 Uninfected
2 Mild
Infection in a patient who is metabolically stable and systemically well, but with ≥1 of the following characterisitics: 3 Moderate
Infection in a patient with metabolic instability (eg, acidosis, severe hyperglycemia, or azotemia) or systemic toxicity as manifested by ≥2 of the following: 4 Severe
5. What is the appropriate route, setting, and duration of antibiotic therapy?
  • The table below describes the recommended route, setting, and duration of antibiotic therapy based on the extent and severity of DFI.
Site of Infection, by Severity or Extent Route of Administration Setting Duration of Therapy
Soft-tissue only Mild (Grade 2) Oral (or topical for superficial infections) Outpatient 1–2 wk
Moderate (Grade 3) Oral (or initial parenteral) Outpatient (or inpatient) 1–3 wk
Severe (Grade 4) Initial parenteral, switch to oral when possible Inpatient, then outpatient 2–4 wk
Bone or joint No residual infected tissue Parenteral or oral Inpatient, then outpatient 2–5 d
Residual infected soft tissue Parenteral or oral Inpatient, then outpatient 1–3 wk
Residual infected, viable bone Initial parenteral, switch to oral when possible Inpatient, then outpatient 4–6 wk
Residual dead bone or no surgery Initial parenteral, switch to oral when possible Inpatient, then outpatient ≥3 mo

Empiric Therapy

Click on the following categories to expand treatment regimens.

    Uninfected (Grade 1)

  ▸  No Evidence of Infection

    Mild (Grade 2)

  ▸  Acute Infection Without Recent Antibiotic Use

  ▸  High Risk for MRSA

    Moderate to Severe (Grade 3–4)

  ▸  Chronic Infection or Recent Antibiotic Use

  ▸  High Risk for MRSA

  ▸  High Risk for Pseudomonas aureuginosa

  ▸  Polymicrobial Infection

Uninfected Wound, No Evidence of Infection
Uninfected wounds should be managed with appropriate wound care.
Antibiotic therapy is not recommended.
Mild DFI, Acute Infection Without Recent Antibiotic Use
Preferred Regimen
Dicloxacillin 125–250 mg PO qid
OR
Clindamycin 150–300 mg PO qid
OR
Cephalexin 500 mg PO qid
OR
Levofloxacin 750 mg PO qd
OR
Amoxicillin-Clavulanate 500 mg PO bid (or 250 mg PO tid)
Usually active against community-associated MRSA, but check macrolide sensitivity and consider ordering a D-test before using for MRSA.
Relatively broad-spectrum oral agent that includes anaerobic coverage.
Mild DFI, High Risk for MRSA
Preferred Regimen
Doxycycline 100 mg PO q12h
OR
TMP–SMX 80-160 mg/400-800 mg PO q12h
Active against many MRSA & some gram-negatives; uncertain against streptococci.
Moderate to Severe DFI, Chronic Infection or Recent Antibiotic Use
Preferred Regimen
Levofloxacin 750 mg IV/PO q24h
OR
Cefoxitin 1 g IV q4h (or 2 g IV q6–8h)
OR
Ceftriaxone 1–2 g/day IV/IM q12–24h
OR
Ampicillin–Sulbactam 1.5–3 g IV/IM q6h
OR
Moxifloxacin 400 mg IV/PO q24h
OR
Ertapenem 1 g IV/IM q24h
OR
Tigecycline 100 mg IV, then 50 mg IV q12h
OR
Imipenem–Cilastatin 0.5–1 g IV q6–8h
Alternative Regimen
Levofloxacin 750 mg IV/PO q24h
OR
Ciprofloxacin 600–1200 mg/day IV q6–12h
OR
Ciprofloxacin 1200–2700 mg IV q6–12h (for more severe cases)
PLUS
Clindamycin 150–300 mg PO qid
Active against MRSA.
Not active against MRSA; consider when ESBL-producing pathogens suspected.
Moderate to Severe DFI, High Risk for MRSA
Preferred Regimen
Linezolid 600 mg IV/PO q12h
OR
Daptomycin 4 mg/kg IV q24h
OR
Vancomycin 15–20 mg/kg IV q8–12h (trough: 10–20 mg/L)
Moderate to Severe DFI, High Risk for Pseudomonas aeruginosa
Preferred Regimen
Piperacillin–Tazobactam 3.375 g IV q6–8h
Moderate to Severe DFI, Polymicrobial Infection
Preferred Regimen
Vancomycin 15–20 mg/kg IV q8–12h (trough: 10–20 mg/L)
OR
Linezolid 600 mg IV/PO q12h
OR
Daptomycin 4 mg/kg IV q24h
PLUS
Piperacillin–Tazobactam 3.375 g IV q6–8h
OR
Imipenem–Cilastatin 0.5–1 g IV q6–8h
OR
Ertapenem 1 g IV/IM q24h
OR
Meropenem 1 g IV q8h
Alternative Regimen
Vancomycin 15–20 mg/kg IV q8–12h (trough: 10–20 mg/L)
OR
Linezolid 600 mg IV/PO q12h
OR
Daptomycin 4 mg/kg IV q24h
PLUS
Ceftazidime 2 g IV q8h
OR
Cefepime 2 g IV q8h
OR
Aztreonam 2 g IV q6–8h
PLUS
Metronidazole 15 mg/kg IV, then 7.5 mg/kg IV q6h

Do's

Don'ts

References

  1. 1.0 1.1 1.2 1.3 Pendsey SP (2010). "Understanding diabetic foot". Int J Diabetes Dev Ctries. 30 (2): 75–9. doi:10.4103/0973-3930.62596. PMC 2878694. PMID 20535310.
  2. Hobizal KB, Wukich DK (2012). "Diabetic foot infections: current concept review". Diabet Foot Ankle. 3. doi:10.3402/dfa.v3i0.18409. PMC 3349147. PMID 22577496.
  3. "Guidelines".
  4. "Guidelines".
  5. 5.0 5.1 American Diabetes Association (2020). "11. Microvascular Complications and Foot Care: Standards of Medical Care in Diabetes-2020". Diabetes Care. 43 (Suppl 1): S135–S151. doi:10.2337/dc20-S011. PMID 31862754.
  6. Rathur HM, Boulton AJ (2007). "The diabetic foot". Clin Dermatol. 25 (1): 109–20. doi:10.1016/j.clindermatol.2006.09.015. PMID 17276208.
  7. Lipsky BA, Berendt AR, Cornia PB, Pile JC, Peters EJ, Armstrong DG; et al. (2012). "2012 Infectious Diseases Society of America clinical practice guideline for the diagnosis and treatment of diabetic foot infections". Clin Infect Dis. 54 (12): e132–73. doi:10.1093/cid/cis346. PMID 22619242.
  8. Wukich DK, Armstrong DG, Attinger CE, Boulton AJ, Burns PR, Frykberg RG; et al. (2013). "Inpatient management of diabetic foot disorders: a clinical guide". Diabetes Care. 36 (9): 2862–71. doi:10.2337/dc12-2712. PMC 3747877. PMID 23970716.