Volume 20, Supplement 1, 2012
Review
Diabetic foot: definitions
Pascale Renato,
Vitale Mario,
Zeppa Pio,
Russo Enrico,
Esposito Silvano
Diabetes is a metabolic disorder characterized by chronic hyperglycemia associated with impaired glucose, lipid and protein metabolism. The purpose of our work is to provide a clear and precise definition of the disease and of his frequent complications: diabetic foot and diabetic foot infection.
Epidemiology of diabetic foot
Leone Sebastiano,
Pascale Renato,
Vitale Mario,
Esposito Silvano
Diabetes is one of the most common diseases and, in many developing and newly industrialized countries, the epidemic is growing at a dizzying rate. The main problems for diabetics are related to chronic complications of the disease. Among the complications of diabetes, the diabetic foot is gaining a new importance because it implies for diabetics the highest number of hospital admissions and considerable costs. In fact, about 15% of diabetics will experience in their life a foot ulcer. The greatest risk for these patients is the amputation. According to several studies, about 25-50% of diabetic patients receive immediate amputation at the time of the first visit due to the infection. Overall, it is estimated that approximately 50-70% of all lower limb amputations are due to diabetes. Therefore, diabetes is the leading cause of non-traumatic amputation of the lower limb in western countries, with a risk in diabetic patients 15 times higher than non-diabetics.
Infected lesions of diabetic foot
Vitale Mario,
Zeppa Pio,
Esposito Isabella,
Esposito Silvano
The diabetic foot lesions are the result of a complex set of factors including peripheral neuropathy, trauma, joint deformities and perfusion abnormalities. The foot becomes vulnerable and insensitive to minor injuries caused by excessive pressure, mechanically or minimum thermal insults that can determine the primum movens of a foot ulcer. Due to the trauma, the subcutaneous tissues are exposed to bacterial colonization. Therefore, the wound can develop an infection. So, the first step in the treatment of the lesion is the evaluation of tissue damage, in order to guide therapy and prognosis. Wagner’s classification, used by over 25 years, is still one of the best known systems of lesion classification; however, it is giving way to the most recent Texas’s classification. However, in both systems infection have a minority role. Therefore, the Infectious Diseases Society of America has developed a classification system that divides infections in mild, moderate and severe. The purpose of this classification is to recognize the severe patients because they require immediate hospitalization, parenteral antibiotic therapy and specific instrumental examinations.
Diabetic foot infections: microbiological aspects
Noviello Silvana,
Esposito Isabella,
Pascale Renato,
Esposito Silvano,
Zeppa Pio
The diagnosis of wound infection is based on clinical signs and local and/or systemic inflammation. Therefore, the examination has a major role in the diagnosis of infected lesions of the foot. Once the clinical diagnosis of infection is made, the next step is to determine the etiology with the aim to undertake a rational and appropriate treatment. The most reliable method for assessing microbiological etiology is the specimen of material from infected lesion to perform a bacterioscopic examination and culture. The microorganisms involved in the etiology of diabetic foot depends on the type of injury and on specific patient features (antibiotic therapy, previous hospitalization). The most frequently detected pathogen is Staphylococcus aureus. Mild infections are mostly caused by Gram positive cocci, with a prevalence of S. aureus. Moderate infections are mostly supported by pyogenic Gram positive cocci, but also Gram-negative bacteria can be involved. In severe infections the etiology is polymicrobial. As regards the involvement of fungi in diabetic foot infections data are few and mostly conflicting.
Management of diabetic foot infections
Esposito Silvano,
Russo Enrico,
Noviello Silvana,
Leone Sebastiano
All infected diabetic foot wounds require antibiotic treatment. Antibiotic treatment is influenced by the patient’s features as the vascular status, the leukocyte function and the kidney activity. The initial antibiotic regimen is usually chosen empirically and it can be modified on the basis of the microbiological information obtained subsequently. The initial empiric therapy should be based, on one hand, on the grade of infected lesion and, secondly, on the epidemiological data.
Almost all of the mild/moderate infected wounds can be treated with antibiotics with a spectrum of activity limited to Gram-positive cocci. Treatment with oral antibiotics is sufficient in most cases in patients with mild/moderate infections. With severe infections is more appropriate to use a broad-spectrum antibiotic therapy. Furthermore it is safer to start a parenteral therapy, possibly modifying it into an oral administration if the patient has stabilized. The most frequently pathogen observed in diabetic foot infections is Staphylococcus aureus. It is important to understand whether there are elements that may lead to the suspicion of MRSA infection in order to establish an appropriate antimicrobial therapy.
Adjuvant treatment of diabetic foot
Lo Pardo Dante,
Pezzuti Gabriela,
Selleri Carmine,
Pepe Stefano,
Esposito Silvano
A diabetic infected foot with erythema and fluctuation can suspect that the infection has passed the fascial compartmental, a condition that requires surgical drainage. Elective amputation may be considered for patients who have recurrent ulcers, irreversible loss of function or injuries that require long-term treatment in the hospital. If the diabetic infected foot appears ischemic it requires a treatment of revascularization. The outcome of revascularization is related with the extension of the damaged artery. The debridement removes the bacterial colonies, promotes granulation tissue and its reepithelialization, also facilitates the collection of samples for microbiological analyses. This procedure can be performed with the classic sharp instruments or with advanced autolytic dressings, maggots or ultrasonic equipment. The use of hyperbaric oxygen therapy in the treatment of infected diabetic foot is controversial because studies in this area are few and methodologically questionable. The same conclusion was reached also for the use of growth factors and skin substitutes.