Management of the diabetic foot is a tremendous challenge. It has been estimated that the annual healthcare costs of caring for the diabetic foot range in the billions.1 Approximately 15 percent of diabetic patients will develop a foot or leg ulceration at some point during the course of their disease and 50 percent of those patients suffer reulceration within 18 months.2 Researchers have observed that the prevalence of neuropathy in the diabetic population is 33.5 percent, the prevalence of vascular disease is 12.7 percent and the prevalence of foot ulcer is 4.75 percent.3
While the debate on a standardized ulcer classification continues, diabetic foot ulcerations have a variety of possible causes, including structural deformity, increased pressure and decreased circulation. However, neuropathy may be the most common risk factor with patients for diabetic infections. Paul Brand, MD, noted this when he discussed the “gift of pain,” which is absent in this patient population. “These patients can quite literally wear a hole in their foot in the same fashion where most people wear a hole in their sock,” adds David G. Armstrong, DPM, MSc, PhD.
Neuropathy in the diabetic patient results from abnormalities in the polyol pathway, problems with the perineural microvasculature, excessive protein kinase C activation and oxidative stress.4 Podiatrists should have a strong understanding of peripheral neuropathy, a devastating consequence of diabetes. Accordingly, these patients should see endocrinologists for diabetes control and neurologists for further diagnosis and treatment.
While vascular disease is not, in and of itself, a major risk factor for development of diabetic foot ulcers, it is associated with poor wound healing.5 In the presence of circulatory disease, one should refer the patient for vascular assessment and possible reconstruction. When patients present with gangrene, making an immediate referral for revascularization is essential in order to salvage as much of the foot as possible and reduce the risk of complete lower extremity amputation. Many cases of gangrene require some level of debridement and amputation. Digital amputation, transmetatarsal amputation, Symes amputation and below knee amputation are possible considerations.6 Appropriate vascular evaluation, reconstruction and treatment are essential to the optimum management of the ischemic diabetic foot wound.7
Lower extremity infections are frequent causes of substantial morbidity and mortality in the diabetic population. These infections consume a large portion of resources expended on diabetic complications.8 In fact, most lower extremity amputations stem from infection. While these infections may present as either monomicrobial or polymicrobial, gram positive bacteria predominate in these infections. Appropriate assessment, management and treatment are essential in the care of these infections and mandate a team approach, including infectious disease consultation and treatment.9
When A Patient Presents With Multiple Digit Gangrene
With this in mind, let us consider a couple of case studies of patients who require multidisciplinary care. We evaluated a 56-year-old female who had diabetes and multiple medical comorbidities. She required extensive medical and surgical evaluation. The patient initially presented with multiple digital gangrene and underlying necrosis (see photo on the left). She had severe peripheral vascular disease with multiple vessel occlusion and stenosis.
The patient underwent a distal pedal revascularization and ultimately underwent transmetatarsal amputation due to underlying necrosis of tissue. The multidisciplinary team allowed the period of demarcation in order to facilitate tissue reperfusion after revascularization. Often, significant tissue healing occurs and allows for more distal salvage than what was considered at the initial presentation. This demarcation period is similar to cases of frostbite in which there is delayed intervention to allow for adequate reperfusion.10
The length of time for delay for proper demarcation varies but has been reported in several studies to range from days to weeks to months. However, this time frame is rather long and may allow for extended periods of exposure to infection. At our facility, we commonly allow up to two weeks for demarcation and subsequently perform an appropriate amputation. Typically, we prefer to perform closed amputations rather than open amputations, which would require subsequent delayed closure.
Treating An Infected Wound In A Senior With Longstanding Diabetic Neuropathy
A 72-year-old male with longstanding diabetes, neuropathy and heart disease presented with a recent onset of a wound to the medial aspect of the right great toe. A local physician had been managing the wound until it developed a large eschar and infection with drainage (see above photo on the left).
The patient was admitted for wound care and infection control. He received a comprehensive evaluation and consultation. We referred the patient to infectious diseases and the patient received subsequent treatment. The patient underwent vascular surgery consultation with invasive angiography.
After obtaining a cardiac consultation and clearance, a vascular surgeon performed a lower extremity bypass on the right leg. In the absence of osteomyelitis and resolved infection, and after a brief period of demarcation and reperfusion, the team decided to perform an escharotomy versus a digital amputation. The resultant wound was healthy with adequate perfusion (see above photo on the right). The wound eventually healed with a period of wound care and offloading. We would have amputated the affected toe if we had encountered underlying necrosis and tissue destruction.
What You Should Know About Preventing Ulcers And Reulceration
Diabetic education and screening programs may reduce the risk of amputation and complications, but there is little evidence base to support these programs. One study suggests the benefit of patient education is short-lived (six months) while another study suggests education has no beneficial effect.11
Clinicians and researchers have long believed the use of therapeutic footwear for diabetic patients is beneficial in both protecting and preventing foot ulcerations. Several journal articles compare and contrast the benefits of such footwear.12-14
Caring for the diabetic foot presents a daunting challenge for many practitioners. The diabetic patient may present with concerns ranging from tinea pedis, onychomycosis and musculoskeletal concerns to severe painful neuropathy, infected ulcerations and even gangrene. As dedicated foot specialists, it is our responsibility and duty to provide the complete spectrum of care for our patients.
Having had the opportunity to oversee a diabetic foot clinic for the last two years has allowed me to witness firsthand how challenging it is to treat. I have been fortunate to be involved in the multidisciplinary team of physicians who have cared for these patients and continue to enjoy the challenge that caring for the diabetic foot presents.
Dr. Espensen currently serves as Section Chair and Chief of Podiatry at Providence St. Joseph Medical Center in Burbank, Calif. He also serves as Associate Director and Director of Research at the Providence Diabetic Foot Center. Along with maintaining a private practice in Burbank, Calif., he serves as contributing editor and consultant for several medical journals and companies. He continues to lecture regularly on the diabetic foot both nationally and internationally.
Dr. Steinberg is a faculty member of the Department of Surgery at the Georgetown University School of Medicine in Washington, D.C.
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