Diabetic Foot Ulcer Classification and Assessment

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Wound Assessment

by the WoundSource Editors

Diabetic foot ulcers (DFUs) are ostensibly the most challenging types of chronic ulcerations to manage, given their multifactorial nature. Thorough, systematic assessment of a patient with a DFU is essential to developing a comprehensive plan of care. To implement the treatment plan successfully, clinicians and patients must work together to address each factor contributing to ulcer development and perpetuation.

Classification of Diabetic Foot Ulcers

Historically, classification and subsequent treatment of DFUs do not adequately include management of concomitant ischemia of peripheral arterial disease (PAD). The Wagner Diabetic Foot Ulcer Grade Classification System, which has been in use since its inception in the 1970s, did not have the capacity to describe ischemic components of DFU. The University of Texas Diabetic Foot Ulcer Classification System, PEDIS (perfusion, extent, depth, infection, and sensation), WIfI Threatened Limb (Wound/Ischemia/Foot Infection), and SINBAD (Site, Ischemia, Neuropathy, Bacterial infection, And Depth) are classification systems that utilize degrees of ischemia as a contributing factor.1

At present, subclassification of DFUs can be divided into three categories: neuropathic, ischemic, and neuroischemic. The most prevalent of the three is the neuroischemic DFU, which comprises approximately 50% of such ulcerations.2 Organization and reproducibility of the assessment process are crucial to success. Workups should include identification of intrinsic and extrinsic factors, both modifiable and non-modifiable. We will review appropriate assessments by using a typical history and physical examination format.

Patient's History

History of Present Illness: Clinicians will often have varied processes for obtaining the same information, but using an assessment model that is reproducible will be most useful. OLDCHARTS (Onset, Location, Duration, Characteristics, History of same symptoms, Aggravating factors, Relieving factors, Timing, Symptoms associated) is one example. Some basic questions you should ask your patient are:

  • Age
  • Sex
  • Ulcer onset/history
    • Any attempted home/self-treatments
    • History of infection
    • Associated symptoms including pain (see mnemonic OLDCHARTS mentioned previously)
    • Any previous treatments including custom footwear or other offloading attempts, exposure to external trauma
  • Lower extremity ischemic symptoms (claudication)
  • Ability to tolerate prescribed treatments including offloading and other therapies (patient may not have functional reserve or strength to ambulate in offloading system)

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Pertinent Medical History and Review of Systems: There is a multitude of comorbid physiologic conditions and contributing factors that negatively affect the healing of DFUs. It is imperative that the patient is managed medically by providers skilled in each specialty respective to the condition being treated (e.g., rheumatologist for autoimmune disease, endocrinologist for metabolic disorders).

  • Diabetes mellitus (DM) history including onset, duration
  • Immunosuppressed state/autoimmune disorders
  • Metabolic disorders (thyroid disease, adrenal disease, obesity, degree of insulin resistance in DM)
  • History of foot deformities, including any previous surgical correction
  • Lymphatic disorders (congenital, acquired, post-operative)
  • Nutritional state, including patient’s health literacy and understanding of personal nutrition needs, ability to prepare food for self, and any financial issues affecting access to food
  • Cardiac history, including ischemic disease, congestive heart failure, or hypertension
  • Renal disease, including chronic kidney disease or end-stage renal disease
  • Collagen vascular disorders
  • Anemia, pernicious or related to chronic disease
  • Other conditions affecting ability to adhere to plan of care, including offloading of the affected limb, other issues affecting general medical management of chronic disease such as debility, weakness/hemiplegia from cerebrovascular accident, retinopathy/vision loss from microvascular complication of DM

Surgical History: Patients with DFUs who have had prior non-traumatic amputation are at greater risk of additional amputation. In addition, patients who have undergone lower extremity vascular procedures may present with atypical lower extremity edema. Moreover, if a patient has a corrective procedure that resulted in resolution of an ulceration, and the same phenomenon occurs on the contralateral limb, it is of great clinical importance to note this in the history because the patient may benefit from repeating the procedure on the affected side.

  • History of surgical correction of foot deformities
  • Previous surgical debridements or amputations
  • History of vascular surgery such as coronary artery bypass grafting requiring vein harvest from the lower extremity or ablations/thrombectomies

Medications: A plethora of medications may affect the healing of DFUs. Patients taking insulin have higher rates of wound healing overall.3 Most other medications to be cognizant of are those that delay healing such as anti-inflammatory drugs; their use on a short-term basis can be beneficial, but in the long term they can be a barrier to healing.

  • Use of oral or injected hypoglycemic agents or insulin
  • Immunosuppressive medications (e.g., methotrexate, antirheumatics, disease-modifying antirheumatic drugs)
  • Corticosteroids
  • Non-steroidal anti-inflammatory drugs

Social History: This portion of the history and physical examination is sometimes overlooked as pertinent to the patient’s overall condition. The patient’s health literacy level should be catered to because interventions that patients do not fully comprehend are far less likely to be followed. The patient should be counseled regarding resources if any gaps in care are encountered (e.g., if the patient does not have running water, referral to case management to seek assistance programs for utilities, etc., may be warranted).

  • Nicotine dependence/tobacco use, including smoking or chewing, vaping with substances containing nicotine
  • Alcohol use
  • Socioeconomic status, capacity to afford medications and prescribed medical treatments
  • Education level and health literacy
  • Occupation, including physical requirements such as standing/weight bearing
  • Exercise, if any
  • Preventive care

Physical Examination

A thorough physical examination will reveal an abundance of useful clinical information. The information garnered will allow for appropriate grading and classification of the DFU, by providing prognostic value and guiding treatment. Some information in the examination may even reveal undiagnosed conditions impeding the healing process (e.g., lower extremity swelling despite adequate elevation and compression may indicate the need for a cardiology referral).

  • Skin
    • General dermatologic assessment for skin quality, trophic changes including xerosis, alopecia, atrophie blanche, previous areas of scarring, condition of digital nails
  • Extremity
    • Fissures, bullae, pre-ulcerative callus, interdigital maceration
    • Wound assessment including wound measurements (length, width, depth), sinus tracts/tunneling or undermining, wound bed description including exposed structures or probe to bone, periwound condition, wound edges/presence of callus, exudate quality, odor, local or spreading signs of infection (DFU surface area is expected to demonstrate 1% to 2% daily reduction in size, which translates to 40% to 50% or greater reduction in size at four weeks4). DFUs should be classified on initial assessment and reclassified as necessary throughout treatment. Appropriate classification and grading are vital to obtaining payer approval for specific therapies including hyperbaric oxygen therapy, cellular and/or tissue-based products, and other adjunctive therapies.
  • Cardiovascular:
    • Lower extremity edema, pitting and nonpitting
    • Vascular assessment
      • Palpation and grading of femoral, popliteal, dorsalis pedis (DP), and posterior tibial (PT) pulses, including auscultation for bruits (PT pulses are absent in a small number of individuals. It should also be noted that the presence of pulses does not rule out presence of PAD).5
      • Evaluate for the “6 Ps”: pain (acute onset), pallor, pulselessness, paresthesias, paralysis, and poikilothermia (temperature change, i.e., cold leg). If critical limb ischemia is suspected, it is a clinical emergency, and the patient should be immediately evaluated by a vascular specialist.
      • Other perfusion diagnostics such as ankle brachial index (ABI), toe brachial index (TCI)/toe pressure, transcutaneous oximetry (transcutaneous oxygen pressure; TcPO2/TCOM), and skin perfusion pressures (SPP) may be performed. ABI is not generally diagnostic in long-standing DM secondary to calcification and macrovascular complications. Toe pressures are better indicative of perfusion because toe vessels are less subject to calcification. ABI with plethysmography can identify extent of disease, by demonstrating triphasic, biphasic, or monophasic arterial waveforms.
  • Neurologic:
    • Sensory neuropathy testing using Semmes-Weinstein monofilament
    • Vibratory sense, position sense, sharp/dull discrimination
  • Musculoskeletal:
    • Gait pattern
    • Assistive devices needed for ambulation
    • Biomechanical abnormalities such as claw toe, hammer toe, bunion, prominent malleoli, or neuroarthropathy
    • Range of motion of ankle/plantar and dorsiflexion (limited dorsiflexion can result in increased plantar pressures on the metatarsal heads)
    • Overall functional status as it contributes to self-care capacity and ability to perform activities of daily living (ADLs)
    • Deep tendon reflexes
    • Inspection of footwear for abnormal wear and tear or any foreign objects that may precipitate foot trauma and subsequent ulceration or infection
  • Psychological
    • Depression is commonly associated with a diagnosis of DFU, especially the primary episode.5

Diagnostic Tests

These data, in isolation, are not always clinically useful. Combining these data with the medical history and physical examination data will further clarify the clinical picture of the patient with a DFU. At times, the data will show a positive correlation (e.g., the wound assessment reveals positive probe to bone, and erythrocyte sedimentation rate [ESR] is 85). Conversely, it may reveal a negative correlation (e.g., the patient may have normal white blood cell (WBC) count, but wound assessment reveals erythema and a purulent, malodorous exudate).

  • Serum laboratory values
    • WBC count (typically elevated with developing infection, but response blunted in some states of severely uncontrolled DM and other disorders)
    • Hemoglobin and hematocrit (Hgb/Hct) (Anemia, acute or chronic, can negative affect already altered states of perfusion)
    • Prealbumin (PAB), transferrin, retinol-binding protein (RBP) (PAB is still standard for nutritional status in chronic wounds but in chronic inflammatory states is not as indicative of true nutritional/protein status. A combination of values may paint a better clinical picture)6
    • ESR(sed rate) and C-reactive protein (CRP) (ESR over 70 unofficially diagnostic of osteomyelitis in patients with DFU)7
    • Blood glucose, glycosylated Hgb (Hgb A1c) (relating to overall disease management. Normalization of glucose levels delays onset of microvascular and macrovascular complications secondary to DM and lessens risk factors such as sensory neuropathy or peripheral vascular disease that can contribute to DM-related foot problems.8)

Conclusions

Accurate assessment and classification guide treatment and provide prognostic information for the patient’s course of care. The goals of assessment should include identification and stratification of risk for progression of ulceration and propensity for development of infection and to confirm the diagnosis by ruling out other etiologies that may require different interventions. Assessment of detailed patient history, disease status of DM including glucose control and medication management, other comorbid conditions, functional status and ability to perform ADLs, social habits such as tobacco use and alcohol intake, and socioeconomic status and health literacy are inherently valuable to forming a comprehensive treatment plan.

References
1. Schaper NC. Diabetic foot ulcer classification system for research purposes: a progress report on criteria for including patients in research studies. Diabetes Metab Res Rev. 2004;20 Suppl 1:S90.
2. Chadwick P, Edmonds M, McCardle J, Armstrong D Best Practice Guidelines (IBPG): Wound Management in Diabetic Foot Ulcers. Wounds International. 2013. http://www.woundsinternational.com/best-practices/view/best-practice-gui.... Accessed August 6, 2018.
3. Vatankhah N, Jahangiri Y, Landry GJ, Moneta GL, Azarbal AF. Effect of systemic insulin treatment on diabetic wound healing. Wound Repair Regen. 2017;25:288–91.
4. Sheehan P, Jones P, Giurini JM, et al. Percent change in wound area of diabetic foot ulcers over a 4-week period is a robust predictor of complete healing in a 12-week prospective trial. Plast Reconstr Surg. 2006;117:239S.
5. Boulton AJM, Armstrong DG, Albert SF, et al. Comprehensive foot examination and risk assessment: a report of the task force of the foot care interest group of the American Diabetes Association, with endorsement by the American Association of Clinical Endocrinologists. Diabetes Care. 2008;31:1679–85.
6. Bharadwaj S, Ginoya S, Tandon P, et al. Malnutrition: laboratory markers vs nutritional assessment. Gastroenterol Rep (Oxf). 2016;4(4):272–80.
7. Khodaee M, Lombardo D, Montgomery LC, Lyon C, Montoya C. Clinical inquiry: what’s the best test for osteomyelitis in patients with diabetic foot ulcers? J Fam Pract. 2015;64(5):309–310, 321.
8. National Diabetes Education Program (NDEP). Feet can last a lifetime: a health care provider’s guide to preventing diabetes foot problems. National Diabetes Education Program. 2000. http://www.algadam.net/images2/Guide-PDF%20%282%29.pdf. Accessed August 6, 2018.

The views and opinions expressed in this blog are solely those of the author, and do not represent the views of WoundSource, Kestrel Health Information, Inc., its affiliates, or subsidiary companies.

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