Approximately 15 percent of all patients with diabetes can be expected to develop ulceration in their lifetime, thus putting them at risk for lower extremity amputation. Treatment for infected diabetic foot wounds accounts for one quarter of all diabetic hospital admissions in the United States and Great Britain.1-3 Patient education, proper footgear and regular foot examination can decrease the frequency and severity of ulceration. However, when ulceration does occur, home care may be a cost-effective intervention that can either avoid or shorten hospital admissions in appropriate cases. Obviously, severe, limb-threatening infection or ulceration requires hospital care. This is especially true in cases complicated by vascular disease that may require angiography and bypass surgery. However, if acute infection has been stabilized and the patient has adequate vascular perfusion (or it has been restored during hospitalization), proper wound care at home can facilitate the completion of wound closure. Such care does require administration of necessary antibiotics, debridement and dressing changes, offloading the ulcerated part, and optimal diabetes management. Evaluating Ulcerations For The Possibility Of Treatment At Home The first step in determining suitability for home care is to establish whether the ulceration is limb threatening or not. A useful system for evaluating the severity of diabetic ulcerations was developed at the University of Texas (see “University Of Texas Wound Classification System” below).4 The classification is based on the depth of the ulceration, presence of infection and degree of ischemia. One will see ischemic ulcers in pulseless feet with thin atrophic skin. These ulcers are usually fibrous or present with an eschar. Little or no granulation tissue is present. Ischemic ulcers are less common than the more typical neuropathic ulceration. Ischemic feet frequently require some form of vascular intervention such as angioplasty or bypass surgery to achieve healing. A Grade III-D ulceration is a deep, infected ischemic ulceration. This ulceration constitutes a limb threatening condition and likely requires hospitalization. Initial treatment includes surgical debridement of necrotic tissue, a bone biopsy and infectious disease consultation to initiate proper long-term antibiotic therapy. Peripheral vascular consultation for angioplasty or bypass surgery may be necessary to achieve healing. If all this is accomplished, one may manage the clean, stable, open wound with home care until closure, which may take six weeks or more. Keep in mind that not all diabetic ulcers are infected. Since most ulcerations are contaminated, cultures are likely to reveal a variety of organisms. The diagnosis of infection depends on clinical signs. These signs may include fever, redness extending from the ulcer site, surrounding edema and purulent drainage. Well-granulated ulcerations that do not probe to bone and exhibit no ascending erythema are not likely to be infected, and do not require antibiotic management. When infection does occur, one should consider the nature of the infection before initiating treatment. Superficial ulcers are typically not limb-threatening when they do not probe to bone and cellulitis is less than 2 cm from the ulceration. Patients who have these ulcers are not seriously ill and there are no signs or symptoms of significant systemic involvement. These patients may do very well with outpatient or home care and oral antibiotics. The American College of Foot and Ankle Surgeons has distinguished between non-limb-threatening infections and limb-threatening infections, advocating that patients with limb-threatening infections be hospitalized, at least initially.5 Patients who have deeper infections that probe to bone and systemic signs such as fever, leukocytosis, hyperglycemia, lymphangitis and edema may have limb-threatening disease. Gangrene, abscess, osteomyelitis and even necrotizing fasciitis may be present. Hospitalization is recommended with the following objectives. One should incise and drain deep abscesses, and debride infected bone and necrotic tissues to viable edges. One usually would do this in the operating room. Obtain deep cultures, perform a bone biopsy and proceed with appropriate antibiotic intervention. If there is an ischemic component, one should obtain a vascular consult. Revascularization procedures are provided if necessary and feasible. Once the patient is medically stable, and the wound appears clean and viable, one may emphasize home care. University Of Texas Wound Classification System4 Grade I-A: non-infected, non-ischemic superficial ulceration Grade I-B: infected, non-ischemic superficial ulceration Grade I-C: ischemic, non-infected superficial ulceration Grade I-D: ischemic and infected superficial ulceration Grade II-A: non-infected, non-ischemic ulcer that penetrates to capsule or bone Grade II-B: infected, non-ischemic ulcer that penetrates to capsule or bone Grade II-C: ischemic, non-infected ulcer that penetrates to capsule or bone Grade II-D: ischemic and infected ulcer that penetrates to capsule or bone Grade III-A: non-infected, non-ischemic ulcer that penetrates to bone or a deep abscess Grade III-B: infected, non-ischemic ulcer that penetrates to bone or a deep abscess Grade III-C: ischemic, non-infected ulcer that penetrates to bone or a deep abscess Grade III-D: ischemic and infected ulcer that penetrates to bone or a deep abscess What You Should Know About Monitoring Infection, Cultures And Antibiotic Selection The principles of treating diabetic foot ulceration can be distilled down to infection control, evaluation of vascular perfusion, optimal metabolic management and pressure relief via offloading. If the infection is not limb-threatening, one may emphasize treatment at home. Using the aforementioned University of Texas evaluation system, the most suitable ulcerations for home care are grade I-A, I-B II-A or II-B. When it comes to grade I-C and II-C ulcers with localized infection, one should take reliable cultures from infected tissues and select an appropriate oral antibiotic therapy based on the culture results. Since grade III ulcerations probe to bone, they are considered, almost by definition, to have osteomyelitis and may require hospitalization to initiate therapy. If osteomyelitis is present, performing bone debridement or obtaining a biopsy is necessary in order to establish the infecting agent. Then one would need to administer long-term (possibly IV) antibiotics.6 The difficulty arises when Grade I and II ulcers are present for a prolonged period of time and deep infection is uncertain. If such an ulcer is present for three months or more, unsuspected osteomyelitis may be present. Obtaining a bone scan or MRI may be helpful to make the diagnosis. One can do this on an outpatient basis for patients without systemic febrile illness. However, be aware these imaging studies are not always conclusive. In highly suspicious cases, one should biopsy and culture the bone underlying the ulceration, and subsequently provide appropriate antibiotic treatment. One may utilize outpatient surgical facilities for this purpose if the patient is stable and you consider the infection to be non-limb-threatening. It is easy to initiate wound care and oral antibiotics in the home setting. If soft tissue infection is present, one should obtain accurate cultures to ensure proper antibiotic therapy. Be aware that an array of organisms can contaminate diabetic wounds. To obtain a reliable culture, one must clean the superficial aspects of the wound and swab the deeper, obviously infected tissues. Samples of deeper or debrided tissue will yield the best bacteriologic information.7 When treating non-limb-threatening infections, one may proceed with empiric broad-spectrum antibiotics (such as cephalosporins, quinolones, or penicillin clavulanate combinations) while awaiting culture results.6 Keep in mind that methicillin resistant Staph aureus (MRSA) is becoming a bigger problem and now there are community-acquired strains of MRSA. If this organism is an infecting agent, IV vancomycin or oral linezolid therapy is indicated. If surgical debridement and long-term IV access is necessary, one can initiate this in the hospital. Once the patient is stable, one can have the patient continue the antibiotic therapy at home. Converting Chronic Wounds Into Wounds That May Be Ready For Home Care One should monitor grade I or II A or B ulcerations for signs of infection and healing on a weekly basis at the least. This can be done by a visiting nurse upon orders from a podiatric physician. If there is no improvement within one or two weeks, and especially if pulses are absent and other signs of ischemia are present, one should obtain a peripheral vascular consultation. Angiography, angioplasty or bypass surgery may be indicated to treat ischemic ulcerations that fail to heal if the patient is a good candidate for such intervention. Keep in mind that even if the patient has adequate perfusion and the infection has been controlled, the ulcer may still fail to heal if the patient has a poor metabolic status. Anemia, poor control of diabetes and nutritional deficits contribute to faulty wound healing. To address these issues, have the patient see a primary physician, internist or endocrinologist.7 Once one has controlled the infection, obtained adequate vascular status and initiated attempts at metabolic control, the wound is ready for home care. Non-infected, neuropathic, non-ischemic ulcerations may present in this condition. Sometimes hospitalization may be required for surgical debridement, initiation of antibiotics or bypass surgery to achieve this appearance. However, once one has brought the wound to a viable appearance, the home is a very acceptable setting for further care. What One Illustrative Case Study Reveals In one case, the patient was a 60-year-old male, who had suffered from type II diabetes for over 20 years. He presented with an infected deep necrotic ulceration of the hallux, which we classified as a III-D ulcer. We performed a hallux and partial first metatarsal amputation to stabilize an acute limb-threatening infection. Our peripheral vascular consultation concurred with the diagnosis of vascular disease, but felt the patient had adequate perfusion for healing. An infectious disease consult recommended six weeks of IV antibiotic therapy based on deep cultures that were taken during surgery and were consistent with osteomyelitis. We stabilized the wound in the hospital to the appearance shown in the above photo with wet to dry saline dressings. The visiting nurse performed wound cleansing and calcium alginate dressing changes every one to two days and monitored for signs of infection. The podiatrist performed debridement every one to two weeks as necessary to maintain a viable wound. The patient used a walker and wheelchair for mobility. In the bottom right photo, one can see the patient’s wound after three weeks of home care. In the bottom left photo, one can see the almost healed wound after six weeks of home care. A Closer Look At Debridement, Dressings And Topicals In The Home Setting Debridement, dressings and offloading are well-established principles of wound healing. These latter measures may not require hospitalization and can be performed in a home care setting. Diabetic ulcerations are usually painless and one can debride these through subcutaneous tissue, tendon or muscle, and sometimes even bone without any anesthesia. There is usually an extensive keratosis that surrounds or covers the ulceration. One can usually remove this to the point where only viable, healthy tissue remains. One should proceed to clean the wound with soap and water, sterile water or saline. Debride with sterile forceps, scissors, tissue nippers or a number 15 scalpel. Once the wound bed is clean and free of any non-viable keratosis, fibrous tissue or necrotic tissue or bone, proceed to re-cleanse the foot with sterile water or saline and apply a dressing. (An exception to the need for debridement is the dry, stable, superficial eschar. If there is no evidence of underlying or ascending infection, one should leave such eschars intact to demarcate and slough as the underlying skin epithelializes. As the eschar becomes loose, it may then be appropriate to proceed with gentle debridement.) The type of dressing one uses depends on the condition of the wound. If one would like additional superficial debridement, using a wet to dry saline dressing will accomplish this. If excessive exudate is present, absorptive dressings like calcium alginate preparations are useful. This material will absorb the exudate yet maintain a physiologically moist interface between the wound itself and the dressing material. Generally speaking, dressings that promote moist environments should only cover the wound. One should avoid maceration of surrounding tissues. Topical hydrogels and gauze will also maintain a moist environment in the ulcer without causing maceration in wounds that do not have excessive exudate. While the frequency of dressing change depends on the amount of exudate, it is usually required between two times daily to every other day. If infection is a concern, a visiting nurse should perform the dressing changes and evaluate the patient for signs of infection. If the ulcer is stable, many patients or family members can be taught to do the dressing changes. A variety of topical products are available to facilitate wound care. One may employ topical enzymes when debridement is required beyond what sharp instrumentation can achieve. When the wound is viable and granulated, the enzymes are not helpful. Hydrogels are an economic topical treatment one can use to maintain a proper moist environment. They are easy to apply under a gauze dressing. Platelet derived growth factors, both synthetic and autologous, have been advocated to facilitate and speed up wound healing. These may be helpful after one has achieved adequate debridement and offloading. However, platelet derived growth factors are quite costly to initiate. Some have argued this cost is offset by more rapid healing times. A number of biological and tissue engineered preparations are also available, but may be difficult to use at home due to temperature and storage requirements. Antiseptics, like peroxide or iodophor solutions, are discouraged because their drying effects are thought to impair wound granulation. Key Insights On Offloading Most diabetic ulcers result from excessive plantar pressure. If that pressure continues after ulceration, logic suggests that the ulcer is unlikely to heal, no matter what type of topical applications one utilizes. The most effective offloading technique is non-weightbearing on the ulcerated foot. However, compliance with crutches, walkers or wheelchairs is difficult to achieve. Several alternatives to complete non-weightbearing are available, but they represent a compromise and do not fully offload the ulcerated foot. These alternatives include the total contact cast (TCC), removable cast walker and the half shoe.8 The effectiveness of these devices appears to vary inversely with the ease of application. Armstrong and his group studied the effectiveness of these devices and found the TCC promotes healing ulcers in the shortest time (4.3 weeks). This compared to 5.6 weeks for the removable cast walker and 5.5 weeks for the half shoe.8 However, the TCC is difficult and time consuming to apply. There is also a risk of cast induced ulceration with this technique. Half shoes, other healing shoes and removable cast walkers may be worn over the wound dressing, and should be used with some sort of gait assisting device, such as a cane or walker, to achieve partial weightbearing. If the patient is unsteady or unsure of how to use the offloading devices, home physical therapy for partial weightbearing gait training may be effective. Wheelchairs with leg lifts for the affected extremity allow mobility with effective offloading. One should emphasize making all efforts to facilitate as little weightbearing as possible on the ulcerated extremity. Heel ulceration is a concern with bedridden patients. One should regularly inspect the heels of both feet and make an effort to cushion or offload the heels while the patient is in bed. Major efforts to accomplish the healing of a midfoot or forefoot ulceration can be totally undone if a patient develops a decubitus ulcer. Managing The Potential Treatment Outcomes A typical plantar diabetic ulceration under home care should heal in approximately six weeks if the patient meets the following parameters: a controlled infection; adequate vascular supply; is metabolically stable with a serum albumin or 3.0 or better; has near normal hemoglobin; well-controlled diabetes; and adequate offloading of the ulcer. One should grade and measure the ulcer on a weekly basis to monitor progress. If you do not see gradual improvement, there is a likely deficiency in one of the aforementioned parameters. If the ulcer is granulated and contracting, even if slower than expected, the prognosis is good. Dysvascular, hypoalbuminemic and other compromised patients can still heal but it will likely take longer. If the wound is not deteriorating in any way, it will likely heal eventually. One can evaluate infection by monitoring white blood cell count and sedimentation rate. If the white blood cell count or sedimentation rate is not normal or not demonstrating decreases from the start of treatment, one should suspect osteomyelitis. If one can probe the wound to bone, osteomyelitis is likely. If one cannot probe to bone, it may be necessary to obtain an X-ray or bone scan to establish the diagnosis. If either is positive, institute treatment with bone debridement, biopsy, culture and appropriate antibiotics as previously discussed, continuing with appropriate wound care. Other causes of wound failure include vascular disease and metabolic impairment. Usually, one would identify vascular insufficiency early in the course of care. If borderline vascular disease is present but has not been treated, and the ulcer is not healing, one should obtain a follow-up consultation with a peripheral vascular surgeon. Patients with low albumin, renal disease or poorly controlled diabetes may fail to heal. If one cannot control these processes, continue with wound care indefinitely unless one decides to consider amputation. If there is uncontrollable infection, necrosis of bone or deep soft tissues that cannot be debrided away or intractable ischemic pain, one should consider amputation. Likewise, if the ulcer care is requiring such prolonged disability that the patient’s overall quality of life is deteriorating, amputation may be a welcome relief. Initially, many patients will resist the recommendation. However, if amputation can be viewed as a rehabilitation step to improve quality of life, the patient will eventually see the advantage of surgery over an indefinite long-term challenge of chronic wound care. If the ulcer heals successfully, the next challenge is to return the patient to community ambulation and protect him or her from further ulceration. Anytime a patient has developed an ulceration, one should consider the patient at high risk for another ulcer. This is especially true of patients who have neuropathy with lost protective sensation, vascular disease or ulcerative deformities such as severe bunions and chronic pressure callus. Educating the patient about risk and foot care is essential to preventing further ulceration. One should emphasize the importance of regular foot exams. Patients may need accommodative shoes. Some may have ulcerative bony deformities, which may be treated surgically if adequate blood flow is present. Other patients may need help with managing nail conditions or chronic pressure keratosis. One should also inspect a patient’s protective shoes and orthotics to ensure their effectiveness. Also ensure the patient is aware that even minor injury can lead to ulceration and infection so he or she should not hesitate to seek medical attention any time the foot appears at risk.9 Final Notes Diabetic foot ulcerations can be successfully managed in the home care setting. This is particularly true in cases where no limb threatening infection is present. In all cases, though, one should emphasize careful, long-term and regular foot examination and care as an integral part of the patient’s diabetes management. Dr. Sage is a Professor and Chief of the Section of Podiatry within the Department of Orthopaedic Surgery at the Loyola University Stritch School of Medicine in Maywood, Ill. Dr. Steinberg (pictured) is a faculty member of the Department of Surgery at the Georgetown University School of Medicine in Washington, D.C.
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