Diabetic Ulcer Diagnosis and Management

The Wound Care Certification Study Guide 2nd edition, editors Jayesh B. Shah, MD, Paul J. Sheffield, PhD, and Caroline E. Fife, MD is the perfect tool for anyone studying to take a wound certification exam. It is fully updated with the latest clinical practices and regulatory and reimbursement information. This all-inclusive study guide includes the following: 

  • Thirty-three informative chapters that review the core principles candidates need to know to obtain wound care certification 
  • A full-length post-course exam complete with answers and explanations 
  • Comprehension questions at the end of each chapter 
  • Over 200 color photos, tables, and diagrams 
  • Guidance on how to choose the certification exam that best meets your needs 
  • Test-taking strategies for success 

The following chapter, Diabetic Ulcer: Diagnosis and Management by Javier La Fontaine, DPM, MS, and Kathren McCarty, DPM, MS, FACFAS printed with permission from Best Publishing Company from the Wound Care Certification Study Guide 2nd edition


Introduction 

This chapter addresses the pathophysiology of diabetic ulcerations, the types of diabetic ulcers (neuropathic, neuroischemic, and ischemic), how to evaluate diabetic wound patients, and the management options for diabetic foot ulcers. Surgical management options include elective foot surgery, prophylactic foot surgery, curative foot surgery, and emergent foot surgery. 

Objective 

Participants should be able to discuss the risk factors for ulceration, contrast the types of amputations (digital, ray, transmetatarsal, Lisfranc, Chopart, Syme, and transtibial), and discuss the wound care protocol recommended after four weeks of insufficient healing. 

I. Diabetic ulcer diagnosis 

  1. Epidemiology of diabetes 
    1. 120,000 amputations a year in the United States 
    2. Two-thirds of those amputations are attributed to diabetic complications 
    3. 85% of all diabetic amputations are preceded by ulceration (Figure 1)
  2. Pathophysiology of diabetic foot ulceration (Figure 2)
    1. Diabetes plays a significant role in the development of plantar pedal ulceration.
    2. Neuropathy, vasculopathy, and deformity are essential for the development of a neuropathic ulceration.
    3. Neuropathy is the most important single independent risk factor.
    4. Neuropathy leads to loss of protective sensation.
    5. Neuropathy leads to deformities via motor neuropathy of intrinsic muscle of the foot. Therefore, deformities, such as hammertoes, will predispose the foot to areas of increased pressure, which in this case would be the dorsum of the toe and the metatarsal head of the respective toe via retrograde force. In the presence of neuropathy the area of pressure will develop callus and subsequently become an ulcer.
    6. Neuropathy, especially autonomic, promotes anhidrosis, which causes dryness of skin and fissures. Both ulcers and fissures, along with vascular disease, place the patient at risk for infection and gangrene.
  3. Evaluating a diabetic wound patient
    1. Poorly controlled diabetes is associated with the development of end organ disease such as arteriovascular disease and peripheral neuropathy. However, the data linking hemoglobin A1c to healing are not strong. Current guidelines suggest that attempting to lower A1c below 7 may be associated with death in older patients. Therefore, while glucose control is always an important component of diabetes management, the possible benefit of very tight glucose control on healing should be weighed against the proven risk of adverse events.
    2. Pertinent medical history should be gathered in relation to cardiovascular disease. Patients with a history of coronary artery disease, stroke, and smoking may have significant peripheral vascular disease, and further vascular evaluation is warranted.
    3. A complete evaluation of the wound is essential to formulate a treatment plan.
    4. Assessment of the contralateral limb should be done as well to screen and compare pathology with the affected limb.
    5. The first assessment of vascular status should be done by palpation of the dorsalis pedis and posterior tibial pulse.
    6. Non-invasive arterial evaluation should be performed in all patients with non-healing wounds or on patients over age 50 with a history of diabetes. This can be done using the ankle-brachial index or other noninvasive methods such as transcutaneous oximetry or skin perfusion pressure.
    7. Palpable pulses may be unreliable in diabetic patients because of Monckeberg’s sclerosis (calcification of the tunica media of vessel wall).
    8. Neuropathy should be assessed as well. Monofilament, vibration, and deep tendon reflexes should be tested to assess the severity of neuropathy.
      1. Peripheral neuropathy screening for loss of protective sensation can be accomplished using the Semmes-Weinstein 5.07 monofilament and deep tendon reflex testing vibration with 128 Hz tuning fork.
    9. There is evidence that neuropathy may have an effect on autoregulation of capillaries and, therefore, poor oxygenation at the wound base.
    10. Infection should be ruled out in diabetic wounds (Figure 3). Although erythema, swelling, heat, and pain are classic signs of infection, it is not always the case in the diabetic wound.
    11. Inflammation is commonly seen in neuropathic ulcers because of repetitive stress, which occurs in the development of the ulcer, as well as an excessive inflammatory response observed in neuropathic limbs (Figure 4).
      1. For example, Charcot neuroarthropathy may simulate an underlying bone infection when in reality there is no infection.
    12. If infection is suspected, deep cultures are preferred.
    13. The deformity that is causing the ulcer should be evaluated.
    14. Identification of the deformity is not only important for wound healing, but also to prevent recurrence.
    15. Structural deformities, such as bunions, hammertoes, and limited joint mobility, need to be recognized for the management of these wounds.
    16. The increased pressure observed is directly proportional to the severity of the deformity. 
  4. Types of diabetic ulcers 
    1. There are three types of ulceration the healthcare professional will encounter. 
      1. Neuropathic ulcer (Figure 5)—the neuropathic ulcer is painless with a hyperkeratotic rim and red granular base. Maceration is usually present underneath the hyperkeratosis. It occurs in locations where there is increased pressure, commonly the plantar aspect of the foot.
      2. Neuroischemic ulcer (Figure 6)—the neuroischemic ulcer is the most difficult ulcer to treat in the foot. It has characteristics of the neuropathic ulcer, but microvascular disease makes this ulcer a challenge to heal. Often noninvasive arterial studies demonstrate mild macrovascular disease. The appearance of the foot is consistent with signs of vascular disease as well as severe neuropathy. The wound base is pink in color mixed with a fibrinous type tissue that recurs even with sharp debridement.
      3. Ischemic ulcer (Figure 7)—the ischemic ulcer has a yellowish or grayish base with a margin that bleeds for a short period of time. This sign is deceptive as the clinician may believe that the wound is well perfused. It is usually painful since the patient may present with rest pain as well. Vascular consultation is imperative for the treatment of this type of wound. 
  5. Prevention of diabetic foot ulceration 
    1. Universal standards of clinical prevention and treatment of ulcerations must be established to ultimately decrease the rate of infection, amputation, and mortality of patients with diabetes. Foot biomechanics, structure, and skin integrity should be evaluated. 
    2. Diabetic patients are more prone to onychomycosis, cutaneous infections, and deformity. 
    3. It has been shown that prescriptive shoe wear, shoe inserts and cushions, and debridement of calluses are crucial for decreasing plantar pressures and redistributing pressure loads. 
    4. It has been shown that prophylactic foot surgeries can be effective in preventing foot ulcers in diabetic patients when indicated. 

II. Management of diabetic foot ulcers 

  1. Treatment of diabetic foot ulceration
    1. Consistent wound measurement
    2. Glucose control
    3. Surgical debridement
    4. Antibiotics
    5. Off-loading
    6. Moist wound environment
    7. Advanced wound care therapies
    8. Vascular and surgical reconstruction
    9. Bed rest or limited activity; cutout felt pads and total contact casting should be used to off-load these wounds.
    10. If after approximately four weeks the wound care protocol is producing insufficient healing, the treatment must be reassessed; determine if edema, blood supply, and/or nutrition are preventing the healing process.
      1. Alternative therapies such as cellular tissue products should be employed.
      2. Hyperbaric oxygen therapy may help in ulcer healing and provide a significant reduction in the risk of major amputation.
    11. After appropriate wound care and debridement, an off-loading modality should be chosen to transfer or decrease the plantar pressure from one specific location to the rest of the plantar aspect of the foot in balanced redistribution. Bony prominences, edema, previous amputation, wound location, and wound care all play important parts in the decision-making process for off-loading.
  2. Surgical management in diabetic wound patients
    1. Sometimes surgical intervention may be necessary. The role of surgical management is a viable option when it comes to successfully treating recurrent diabetic ulcerations, infections, and other related complications that exist in the foot and ankle. In regard to surgical intervention for the diabetic foot, Armstrong and Frykberg have offered the following classifications.
      1. Class I: elective foot surgery, performed to treat a painful deformity in a patient without loss of protective sensation
      2. Class II: prophylactic foot surgery, performed to reduce the risk of ulceration or reulceration in patients with a loss of protective sensation, but without an open wound
      3. Class III: curative foot surgery, performed to assist in healing an open wound
      4. Class IV: emergent foot surgery, performed to arrest or limit the progression of acute infection
    2. Whether surgical intervention is curative, prophylactic, or elective, the patient with diabetes should be fully assessed preoperatively for the degree of deformity, history of ulcerations, general physical condition, vascular status, and impairment of glucose control.
    3. When surgery is emergent, the primary surgical intervention should be done immediately with staged additional procedures to follow after the above considerations have been addressed.
    4. Prophylactic and elective surgery can successfully prevent future ulcerations. Withholding surgical management of deformities in the well-controlled diabetic patient may place the foot at future risk for ulceration and amputation.
    5. Failure to remove the deformity can prove more dangerous than the judicious use of surgery to relieve bony pressure.
  3. Elective surgery
    1. There are several goals for elective surgery candidates:
      1. Prevention of recurrent ulceration
      2. Reduction of pressure, primarily over bony prominences
      3. Establishment of a functional foot
  4. Amputation is usually reserved for emergent cases to treat severe infection.
    1. Amputation and plastic surgery techniques may actually be used to cure persistent problem wounds and improve quality of life (QOL).
    2. Several recent studies have shown that patients may prefer and enjoy a better QOL with amputation and a closed surgical site versus continual, wearisome treatments for a chronic or recurrent open wound.
    3. Surgeons must weigh many considerations in order to successfully plan the appropriate level of amputation. These factors include tissue viability (e.g., presence of ulcerations, tissue deficits), micro- and macrovascular circulation, anatomy and biomechanical function, cardiac demand and energy expenditure, and rehabilitation potential.
    4. Also, the reality that one amputation can lead to another in the future due to the creation of biomechanical abnormalities or a worsening of disease must be considered.
    5. Maintaining toe-off and propulsion in the gait cycle to reduce transfer pressures to adjacent metatarsals and digits should be achieved, if possible.
    6. The levels of amputation in the lower extremity include: digital (Figure 8), ray (Figure 9), transmetatarsal (Figures 10a and 10b), Lisfranc (Figure 11), Chopart (Figure 12), Syme (Figure 13), and transtibial (Figure 14).
  5. Some other possible surgeries include:
    1. First ray surgery (e.g., Keller arthroplasty, bunionectomy, sesamoidectomy, first metatarsal osteotomy)
    2. First metatarsal-medial cuneiform fusion
    3. Digital surgery (e.g., hammertoe repair, lesser metatarsal osteotomy, resection of a lesser metatarsal head, nail avulsion for ingrown nails), exostectomy
    4. Midfoot and rear foot arthrodesis
    5. Achilles tendon lengthening
  6. Following surgery, appropriate accommodative or off-loading shoe gear must be fabricated and used daily to prevent future ulceration (refer to Chapter 20). 

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Figures

Figure 1: Diabetic preulcer at the hallux.

Figure 2: Neuropathic diabetic foot ulceration.

Figure 3: Diabetic foot infection

Figure 4: Inflammation secondary to repetitive stress.

Figure 5: Neuropathic ulcer.

Figure 6: Neuroischemic ulceration.

Figure 7: Ischemic ulcer.

Figure 8: Digital amputation.

Figure 9: Partial ray amputation.

Figures 10a: Low transmetatarsal amputation.

Figures 10b: Low transmetatarsal amputation.

Figure 11: Lisfranc amputation.

Figure 12: Chopart amputation.

Figure 13: Syme amputation.

Figure 14: Transtibial amputation (BKA).

Resources

  1. Frykberg RG, Armstrong DG, Giurini J, et al. Diabetic foot disorders: a clinical practice guideline. American College of Foot and Ankle Surgeons. J Foot Ankle Surg. 2000; 39(5 Suppl):S1-60.
  2. Armstrong DG, Lavery LA, Harkless LB. University of Texas classification system for diabetic foot wounds. Diabetes Care. 1998; 21:855-9.
  3. Kahn KH, Derksen TA, Steinberg JS. Diabetic foot wounds. In: Sheffield PJ, Fife CE, editors. Wound Care Practice. 2nd ed. North Palm Beach: Best Publishing Company; 2007: 405-30.
  4. Bosker GW, LaFontine J. Orthotics and prosthetics in wound care. In: Sheffield PJ, Fife CE, editors. Wound Care Practice. 2nd ed. North Palm Beach: Best Publishing Company; 2007: 901-20.
  5. Malone M, Bowling FL, Gannass A, Jude EB, Boulton AJ. Deep wound cultures correlate well with bone biopsy culture in diabetic foot osteomyelitis. Diabetes Metab Res Rev. 2013 Oct; 29(7):546-50.
  6. La Fontaine J, Harkless LB, Davis CE, Allen MA, Shireman PK. Current concepts in diabetic microvascular dysfunction. J Am Podiatr Med Assoc. 2006 May-Jun; 96(3):245-52.
  7. Infectious Diseases Society of America. IDSA Infections by Organ System: Diabetic Foot Infections [Internet]. 2012. Accessed at: http:// www.idsociety.org/Organ_System/#DiabeticFootInfections.

Sample Questions

  1. What percentage of diabetic foot amputations is preceded by ulcers? 
    1. 35% 
    2. 50% 
    3. 75% 
    4. 85% 
  2. The most important single independent risk factor for ulceration is: 
    1. Peripheral vascular disease 
    2. Neuropathy 
    3. Foot deformity 
    4. History of prior amputations 
  3. Advanced wound modalities might be considered if a diabetic wound is not progressing after _____ of standard wound care. 
    1. Two weeks 
    2. Four weeks 
    3. Six weeks 
    4. Eight weeks 
  4. The Semmes-Weinstein test is used to assess: 
    1. Blood flow to the feet 
    2. Protective sensation of the feet 
    3. Pressure on the feet 
    4. Temperature of the feet
  5. All of the following are treatments are considered standards of care for foot ulcers with adequate blood flow except:
    1. Debridement
    2. Off-loading
    3. Antibiotics
    4. Glucose control
  6. Which of the following can lead to an ulcer in the presence of neuropathy and vascular disease?
    1. Hammertoe
    2. Anhidrosis
    3. Callus
    4. All of the above
  7. The most important method of treatment to heal a plantar foot ulcer is:
    1. Moisturizer
    2. Off-loading
    3. Collagenase
    4. A swab culture
  8. When foot ulcers continue to recur and obvious deformity exists, the best option is:
    1. Casting
    2. Diabetic shoes
    3. Surgical correction
    4. Dressing changes and hope it does not get infected
  9. Sometimes palpable pulses are unreliable in the diabetic patient because of:
    1. Loss of protective sensation
    2. The diabetes
    3. Monckeberg’s sclerosis
    4. Lack of pedal hair
  10. A patient presents to the emergency room and upon evaluation is diagnosed with gas gangrene. The podiatrist determined he has to perform surgery immediately. What is the class of surgery?
    1. Elective
    2. Emergent
    3. Curative
    4. Prophylactic

Answer Key

  1. (d) 85% of diabetic foot amputations are preceded by ulcers.
  2. (b) The most important single independent risk factor for ulceration is neuropathy. Patients with neuropathy do not feel sensation, and ulceration occurs when patients do not wear any protective footwear.
  3. (b) Advanced wound modalities may be considered if a diabetic wound is not progressing after standard wound management for four weeks.
  4. (b) The Semmes-Weinstein test is used to assess the protective sensation of feet.
  5. (c) Among the treatments listed, debridement, off-loading, and glucose control are considered standards of care for foot ulcers with adequate blood flow. Antibiotics are required only when infection is present. (7)
  6. (d) Hammer toe, anhidrosis, and callus can lead to an ulcer in the presence of neuropathy and vascular disease. Any area at risk to develop an open wound will be complicated with vascular disease.
  7. (b) The most important treatment to heal a plantar foot ulcer is off-loading. Plantar foot ulcers will not heal with persistent trauma at the wound base. Moisturizer is needed for dry, cracked skin common to diabetics, but it is not a treatment to heal plantar foot ulcers. Collagenase is used for enzymatic debridement, which may be necessary in the treatment of diabetic plantar foot ulcers, but it is not the most important treatment. Swab culture is necessary if a diabetic foot ulcer is infected.
  8. (c) When foot ulcers continue to recur and obvious deformity exists, the best option is surgical correction. Rigid foot deformities often cannot be off-loaded properly. Casting is good for healing diabetic foot ulcers but will not prevent reoccurrence. Diabetic shoes are good for prevention; however, when foot ulcers continue to reoccur secondary to foot deformity they are not the best choice for prevention. Dressing changes are necessary for healing diabetic foot ulcers, not to prevent ulceration in the presence of foot deformities.
  9. (c) Palpable pulses may be unreliable in the diabetic patient because of Monckeberg’s sclerosis; the calcification of the media makes the arterial wall easily palpable even with diminished blood flow.
  10. (b) As gas gangrene is a limb threatening infection, it is considered an emergent procedure. 

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