Diabetic foot syndrome is a pathological condition of the foot in diabetes mellitus, which occurs against a background of peripheral nerves, skin and soft tissues, bones and joints, and is manifested by acute and chronic ulcers, osteo-articular lesions and purulent necrotic processes.
There are three forms of diabetic foot syndrome: neuropathic, ischemic and mixed (neuroischemic). 60–70% of cases of diabetic foot syndrome are neuropathic.
Neuropathic form. Initially, the development of diabetic neuropathy affects the distal nerves, and the longest nerves are affected. As a result of the defeat of the vegetative fibers that make up these nerves, there is a shortage of trophic impulses to the muscles, tendons, ligaments, bones and skin, which leads to their hygrotrophy. The consequence of malnutrition is the deformity of the affected foot. In this case, a redistribution of the load on the foot occurs, which is accompanied by an excessive increase in it in some areas. Such areas may be the heads of the metatarsal bones, which will manifest as a thickening of the skin and the formation of hyperkeratosis in these areas. As a result of the fact that these areas of the foot experience constant pressure, the soft tissues of these areas undergo inflammatory autolysis. All these mechanisms ultimately lead to the formation of an ulcer defect. Since there is a dysfunction of the sweat glands, the skin becomes dry and cracks easily appear on it. As a result of the violation of the painful sensation of sensitivity, the patient may not notice this. In the future, infection of the lesion sites occurs, which leads to the appearance of ulcers. Their formation is promoted by the immunodeficiency arising from the decomposition of diabetes mellitus. Pathogenic microorganisms, which in most cases infect small wounds, are staphylococci, streptococci and bacteria of the intestinal group. The development of the neuropathic form of the diabetic foot is accompanied by a violation of the tone of the vessels of the lower extremities and the opening of arteriovenous shunts. This occurs as a result of an imbalance between the innervation of adrenergic and cholinergic vessels. As a result of the expansion of the vessels of the foot, its swelling and temperature rise develop.
Due to the discovery of shunts, tissue hypoperfusion and the phenomenon of robbery develop. Under the influence of edema of the foot, there can be an increase in compression of the arterial vessels and ischemia of the distal foot (symptom of a blue finger).
The clinic is characterized by three types of lesions. They include neuropathic ulcer, osteoarthropathy and neuropathic edema. Ulcers are most often located in the area of the sole, as well as in the intervals between the toes of the foot. Neuropathic osteoarthropathy develops as a result of osteoporosis, osteolysis and hyperostosis, that is, under the influence of dystrophic processes in the osteo-articular apparatus of the foot. With neuropathy, spontaneous bone fractures can occur. In some cases, these fractures are painless. In this case, palpation of the foot is marked by its swelling and hyperemia. Destruction in the osteo-ligamentous apparatus can take quite a long time. This is usually accompanied by the formation of severe bone deformity, which is called the Charcot joint. Neuropathic edema develops as a result of impaired regulation of tone in small vessels of the foot and the opening of shunts.
The treatment includes several measures: attaining compensation for diabetes mellitus, antibiotic therapy, wound treatment, rest and unloading of the foot, removal of the hyperkeratosis area and wearing specially selected shoes.
Compensation of metabolic processes in diabetes mellitus is achieved by high doses of insulin. Such therapy in diabetes mellitus type II is temporary.
Therapy with the help of bacterial preparations is carried out according to the general principle. In most cases, infection of the foot defects is gram-positive and Gram-negative valuable cocci, E. coli, clostridia and anaerobic microorganisms. As a rule, a broad-spectrum antibiotic is prescribed or a combination of several drugs. This is due to the fact that usually the pathogenic flora is mixed.
The duration of this type of therapy can be up to several months, which is determined by the depth and prevalence of the pathological process. If antibacterial therapy is carried out for a long time, it is necessary to re-conduct a microbiological study, the purpose of which is to detect the resulting strains that are resistant to this drug. In case of a neuropathic or mixed diabetic foot, it is necessary to unload it until recovery.
If this technique is followed, the ulcers can heal within a few weeks. If patients have fractures or a joint arco, then the unloading of the limb should be carried out until the bones are completely bonded
In addition to these methods, it is mandatory to conduct local wound treatment, which includes treatment of the edges of the ulcer, removal of necrotic tissue within healthy ones, as well as ensuring asepsis of the wound surface. A solution of dioxidine 0.25–0.5% or 1% is sufficiently widely used. You can also use chlorhexidine solution. If a plaque consisting of fibrin is present on the wound surface, then proteolytics are used.
The ischemic form of diabetic foot syndrome develops when the main blood flow is disturbed in the limbs, which occurs with the development of atherosclerotic lesions of the arteries.
The skin on the affected foot takes on a pale or cyanotic hue. In more rare cases, as a result of the expansion of the superficial capillaries, the skin becomes rosaceous red. The expansion of these vessels occurs during ischemia.
In the ischemic form of the diabetic foot, the skin becomes cold to the touch. Ulcers form on the tips of the toes of the foot and on the edge of the heel. Palpation of the artery of the foot, as well as in the popliteal and femoral arteries is weakened or may be absent altogether, which is noted in the case of stenosis of the vessel, which exceeds 90% of its lumen. Auscultation of large arteries in some cases determines systolic murmur. In many cases, this form of diabetes mellitus is characterized by the appearance of painful symptoms.
Instrumental research methods are used to determine the state of arterial blood flow in the vessels of the lower extremities. The dopplerographic method is used to measure the palm-shoulder index. This indicator is measured by the ratio of the systolic pressure of the artery of the foot and the brachial artery.
Normally, this ratio is 1.0 or more. In the case of atherosclerotic lesions of the arteries of the lower extremities, a decrease of this indicator to 0.8 is observed. If the indicator turns out to be 0.5 or less, then this indicates a high probability of necrosis.
In addition to dopplerography, if there is a need, angiography of the vessels of the lower extremities, computed tomography, magnetic resonance imaging, and ultrasound scanning of these vessels are performed.
As with the neuropathic form, it is necessary to achieve compensation for diabetes mellitus. The lesion of the lower limb in this form of diabetic foot can be of varying severity.
The severity of the process is usually determined by three factors, including the severity of arterial stenosis, the degree of development of collateral blood flow in the limb, and the state of the blood coagulation system.
The usual treatment method, which is preferred in the ischemic form of the diabetic foot, is to perform a revascularization operation. Such operations include: the formation of bypass anastomoses and thrombendarterectomy.
Minimally invasive surgeries can also be used, such as laser angioplasty, cross-percutaneous transluminal angioplasty, and a combination of local fibrinolysis with percutaneous transluminal angioplasty and aspiration thrombectomy. In case if necrotic and ulcerative lesions are absent, walking is recommended for 1-2 hours per day, which contributes to the development of collateral blood flow in the limb (ergotherapy). For the prevention of thrombosis, the use of aspirin at a dose of 100 mg per day and anticoagulants is recommended. If blood clots are already present, fibrinolytics are used. In the case when the purulent-necrotic process in any variant of the diabetic foot is quite extensive, the issue of carrying out the amputation of the lower limb is resolved.
The main method of preventing the development of diabetic foot syndrome is adequate treatment of diabetes mellitus and maintaining the compensation of metabolic processes at the optimum level. At each visit to the doctor, an examination of the patient’s lower limbs is necessary.
Such examinations should be carried out at least 1 time in 6 months. It is also important to conduct training for patients with diabetes, which includes the rules of foot care. It is necessary to maintain cleanliness and dryness of the legs, to hold warm foot baths, to apply creams to prevent the appearance of cracks on the skin.