Diabetic Foot

　　The causes of diabetic foot are multifactorial, with diabetic neuropathy, peripheral vascular disease, and microcirculatory disorders being the main causes. These can exist alone or in combination with other factors. Other factors, such as foot structural deformities, abnormal gait, skin or toenail deformities, injuries, and infections, are also important precipitating factors for the development of diabetic foot.

　　Vascular and neurological disorders in diabetes are the basic causes of complications associated with diabetic foot. The feet of diabetics are particularly prone to vascular and neurological disorders, which mutually affect each other, leading to a series of clinical foot diseases, including toe diseases, corn formation, skin damage, and foot ulcers. Musculoskeletal lesions can lead to foot deformity. Due to neurological disorders, diabetics often lose or reduce sensation in their feet, making them more susceptible to injury. Even minor injuries can quickly lead to ulcers, infections, and gangrene, eventually necessitating amputation. The incidence of diabetic foot has significantly increased, which is related to the following factors:

　　① The increase in the global number of diabetic patients.

　　② The lifespan of diabetic patients has extended, thereby extending the duration of the disease.

　　③ The increase in the aging population, the incidence of diabetic foot varies in different countries, accounting for about 6% to 12% of hospitalized diabetic patients. In the United States, more than 40,000 people undergo diabetic amputation each year, and in fact, 50% of non-traumatic amputations are due to diabetes. The risk of lower limb amputation in diabetics is 15 times higher than in non-diabetics.

　　In severe cases of diabetic foot, skin breakdown, tissue ulceration, and even necrosis may occur. Additionally, due to numbness or loss of sensation, insensitivity to overheated or cold objects may lead to burns or frostbite. Diabetic foot can induce diabetic limb gangrene, which is a chronic, progressive limb ischemia, pain, numbness, and ulcerative infection, primarily caused by large, medium, and microcirculatory vessel lesions, peripheral nerve lesions, and various injuries, along with complications from infections.

　　The clinical manifestations of diabetic foot are related to five aspects of lesions: neurological disorders, vascular disorders, biomechanical abnormalities, formation of lower limb ulcers and infection, and the main symptoms include general foot symptoms and ischemic symptoms.

　　(1) General manifestations of the foot:Due to neurological damage, the skin of the affected limb is dry without sweat; there are tingling, burning, numbness, delayed or lost sensation, appearing in a stocking-like pattern, feeling like stepping on cotton; due to limb malnutrition, muscle atrophy, the normal traction tension balance of flexor and extensor muscles is lost, causing the bones to sink, resulting in toe joint curvature, forming bow feet, hammer toes, claw toes, and other foot deformities. When the patient's bones and joints and surrounding soft tissues are damaged, continued walking can easily cause bone and joint and ligament injuries, leading to multiple fractures and ligament ruptures, forming Charcot joints. X-ray examination often shows bone destruction, and some small bone fragments may be detached from the periosteum, causing necrotic bone and affecting the healing of gangrene.

　　(2) The main manifestations of ischemia:Common symptoms include skin malnutrition and muscle atrophy, dry skin with poor elasticity, hair loss, decreased skin temperature, hyperpigmentation, decreased limb artery pulsation or disappearance, vascular stricture with audible vascular murmurs. The most typical symptom is intermittent claudication, rest pain, difficulty in squatting and standing up. When the patient's limb skin is damaged or spontaneously forms blisters and becomes infected, ulcers, gangrene, or necrosis may occur.

　　Diabetes can lead to many complications, and diabetic foot is one of the very common and serious diabetic complications. Therefore, diabetic patients should prevent the occurrence of diabetic foot, so what should be paid attention to in the prevention of diabetic foot?

　　1. To prevent diabetic foot, it is important to control weight, blood sugar, blood pressure, and blood lipids, actively treat diabetes, and strictly control hyperglycemia; reasonably distribute diet, strictly control hyperlipidemia, and various factors that lead to early atherosclerosis.

　　2. To prevent diabetic foot, it is important to inspect the feet daily. Before going to bed every day, diabetic foot patients must check their feet to see if there are any injuries. Pay close attention to the color, temperature, and humidity of the skin, check for edema, skin damage, pain level, as well as blood vessel pulsation, sensation, movement, and reflexes, and look for blisters, skin cracks, abrasions, corns, calluses, athlete's foot, and paronychia, among others. If any are found, they should be treated and treated promptly.

　　3. To prevent diabetic foot, foot hygiene should be maintained. Every evening, wash your feet with warm water (39℃~40℃) and soft soap, as water temperature should not be too high to avoid skin burns. The soaking time should not be too long, not exceeding 10 minutes. After washing, dry the spaces between the toes with a soft, absorbent towel.

　　4. To prevent diabetic foot, it is important to keep the skin moisturized. Patients should apply a lubricant such as sheep fat oil to moisturize their feet every day and gently and thoroughly massage the skin. Shoes should be spacious, comfortable, and fit well, allowing the toes to extend fully inside the shoe and have slight movement. Good ventilation is required, with leather or cloth shoes being preferable.

　　5. To prevent diabetic foot, it is necessary to exercise daily, gently massage the feet and lower legs to improve local blood circulation. Smoking and drinking are strictly prohibited, which is beneficial for preventing vascular and neurological complications.

　　Pain, numbness, intermittent limping, changes in skin temperature, edema, and foot necrosis and other symptoms can all be considered within the scope of 'diabetic foot'.

　　In diagnosis, it is necessary to understand the duration of diabetes in patients, the method of treatment, and other complications, identify the cause, duration, degree, and progression of foot ulcers; pay attention to the appearance, range, depth, temperature, and smell of the ulcer surface, and at the same time determine whether the foot has deformity, edema, soft tissue infection, or osteomyelitis. Check the condition of the opposite limb of the patient and whether the shoes and socks are suitable. In auxiliary examinations, the following examinations can be performed.

　　1. Neurological examination

　　The purpose is to understand whether the patient still has protective neural sensation. The simplest and most common method is to use a special 10-gram nylon thread, one end touching the big toe, heel, and lateral part of the anterior sole of the patient's foot, pressing the other end of the nylon thread with the hand, and gently applying pressure to make the nylon thread bend. If the patient can feel the nylon thread on the sole or toe at this time, it is normal; otherwise, it is abnormal. In addition, a tuning fork can also be used to check the patient's sense of vibration.

　　2. Skin temperature examination

　　Check the patient's sense of temperature change in the skin to determine whether the nervous function is damaged. There are qualitative and quantitative inspections. Qualitative inspection involves placing a tuning fork or a thin stainless steel rod in a cup of hot water, removing it, and measuring the patient's skin sensation at different locations, while comparing with normal people. Quantitative inspection requires instruments.

　　3. Pressure measurement

　　Understand whether the patient has abnormal foot pressure by measuring the pressure at different parts of the foot. Usually, the subject stands on a flat plate with multiple pressure-sensitive sensors, and the scanning imaging is analyzed on the computer.

　　4. Peripheral vascular examination

　　The simplest method is to use hands to feel the pulse of the dorsal or posterior tibial artery to understand the changes in large blood vessels of the foot. The disappearance of the fluctuation indicates severe large blood vessel lesions and requires further examination.

　　(1) Vascular ultrasound examination: by examining to determine whether there is stenosis or occlusion in the blood vessels.

　　(2) Ankle-Brachial Index: reflects the blood pressure and vascular status of the lower limbs, the normal value is 1.0-1.4; <0.9 is mild ischemia, 0.5~0.7 is moderate ischemia, and <0.5 is severe ischemia. Severe ischemia is prone to cause gangrene of the lower limb (or toes).

　　(3) Angiography: understand the degree and location of lower limb vascular occlusion, and provide evidence for amputation level or vascular bypass surgery.

　　(4) Transcutaneous oxygen tension measurement: reflects the status of microcirculation and also reflects the blood supply status of the surrounding arteries.

　　(5) Hemorheological examination: whole blood viscosity, plasma specific viscosity, and reduced whole blood viscosity; red blood cell aggregation index, red blood cell rigidity index; determination of plasma fibrinogen content.

　　5. Examination of ulcer with infection

　　Examine suspected infected ulcers with a probe, and if sinus tracts or bone tissue are found, consider osteomyelitis. At the same time, use a probe to take a specimen from the deep part of the ulcer for bacterial culture to increase the specificity of isolating infected bacteria. Deep infection or bone lesions can also be differentiated by methods such as X-ray plain films, isotope scanning, or magnetic resonance imaging.

　　6. Examination of Charcot joint disease

　　Patients with a long history of diabetes may develop Charcot joint disease. Specialized examination and diagnosis are required.

　　The dietary precautions for diabetic foot disease include the arrangement of calories. In principle, it is necessary to fully consider the reduction of the burden on the insulin β cells while ensuring the normal growth and development of the body. Have regular meal times and avoid snacking.

　　Dietary restriction is also one of the dietary precautions for diabetic foot disease. The taste should be light, and low-sodium diet should be adopted as much as possible to prevent the occurrence of hypertension. It is generally good to limit salt to less than 10g per day.

　　Eat less, and never eat in large quantities. Eating in large quantities may cause a rapid increase in blood sugar, and prolonged high blood sugar will increase the burden on the pancreas. High blood sugar for 2 hours will increase the cytotoxic effect of high blood sugar, causing pancreas damage and edema.

　　Diversify food types. Mainly provide foods rich in carbohydrates and B vitamins. Foods rich in protein, fat, vitamin A or B, and minerals are animal foods and dried beans. Foods rich in dietary fiber, minerals, vitamins, and food are mainly vegetables and fruits.

　　The treatment of diabetic foot focuses on prevention, trying to avoid foot injuries, such as wearing comfortable and fitting shoes and socks to avoid skin wear; if vision is poor, do not trim the toenails; wash feet with warm water to avoid burns, and so on.

　　(1) General treatment:In addition to strictly controlling blood sugar and improving the overall health level, it is necessary to eliminate some known risk factors for vascular lesions, such as treating hypertension, lowering blood lipids, and avoiding smoking.

　　(2) Removal of edema:All ulcers are difficult to heal as long as there is edema, and this has nothing to do with the cause of the ulcer. Diuretics or ACE-I can be used for treatment.

　　(3) Treatment of neuropathic foot ulcers:90% of neuropathic ulcers can be healed through conservative treatment. The key is to reduce the pressure load on the foot. Reducing the load means avoiding all mechanical pressures applied to the affected limb. It is the basic requirement for the healing of the affected foot. The pressure on the patient's foot can be changed by special orthopedic shoes or foot orthopedic devices. In addition, the frequency of dressing changes and local medication should be determined according to the depth, size of the area, amount of exudate, and whether there is infection.