Diabetic foot disease

Introduction Diabetic foot refers to the disease state in which the lower limb protection function is reduced due to neuropathy in the foot of diabetic patients, and the disease of ulcer and gangrene is caused by microcirculation disorder caused by insufficient perfusion of arteries. The diabetic foot is a serious complication of diabetes. It is one of the important reasons for the disability and even death of diabetic patients, which not only causes pain to the patients, but also adds a huge economic burden.

Cause

Ulcer (20%):

Many foot complications in diabetic patients result from sensory neuropathy and mild autonomic and motor neuropathy. Among them, sensory neuropathy combined with excessive mechanical stress is the main initiating factor causing foot ulcers and infections. Inflammation and tissue damage are the result of a certain degree of repeated stress acting on a particular area that loses sensation. Pressure or shear from the ground, shoes or other adjacent toes causes ulceration, which is often exacerbated by the presence of bony due to the lack of normal neuroprotective mechanisms. The autonomic nervous system lesions cause normal skin perspiration regulation, skin temperature regulation, and loss of blood regulation, resulting in reduced local tissue flexibility, thick sputum formation, and more fragility and cracking. In addition, the loss of normal wicking ability blocks the rehydration of local tissues, causing further destruction of the tissue, making the deep tissue more susceptible to bacterial colonization. Motor neuropathy also plays a role in the pathogenesis of diabetic foot, and the contracture of the internal muscle of the foot causes a typical claw-toed deformity. Over-extension of the metatarsophalangeal joint has also been shown to directly increase the pressure on the humeral head, making it more susceptible to ulcer formation. The proximal toe joint flexion causes an increased risk of ulceration of the dorsal joint of the interphalangeal joint and the metatarsal tip, and vascular lesions make the damaged tissue difficult to heal.

Infection (30%):

Autonomic dysfunction leads to destruction of skin and soft tissue, causing invasion of foreign bacteria. Changes in chemical tropism lead to inefficient white blood cell responses. In addition, hyperglycemia, decreased oxygen partial pressure, and malnutrition can collectively trigger tissue edema, acid accumulation, hypertonicity, and inefficient anaerobic metabolism. This type of environment is suitable for bacterial growth and hinders the function of white blood cells. In addition, vascular disease can cause restricted transport of antibiotics, further reducing the efficiency of bacterial clearance, leading to local soft tissue infections and even the formation of osteomyelitis.

Charcot arthropathy (10%):

For progressive weight-bearing joint destructive lesions. Neurotrauma theory believes that loss of pain and proprioception after repeated mechanical damage or single trauma can lead to Charcot joint disease. Neurovascular theory believes that increased blood supply in the lesion area caused by autonomic dysfunction leads to bone resorption and The strength is weakened, and in turn, repeated trauma causes bone destruction and instability.

Toe deformity (30%):

Motor neuropathy causes contracture of the intrinsic muscle of the foot, resulting in a typical claw toe deformity.

an examination

Related inspection

Blood glucose, glucose, insulin release test, angiography

Check the body

A thorough examination of the lower part of the lower extremity knee joint should be performed. Physical examinations should be conducted at least once a year and should be more frequent for high-risk groups. Problems that need to be observed and recorded include: abnormal gait, wear of the shoes, and the presence or absence of foreign objects protruding into the interior of the shoe, pulsation of the blood vessels, hair growth, skin temperature and capillary refilling, observing deformity and tissue destruction of the foot and heel. The location and size of the ulcer, the presence of edema or inflammation. Also check the stability of the joints and the strength of the muscles.

2. Comprehensive neurological examination

Inspection of reflection, motion and sensory functions. Qualitative sensory examinations such as light touch, two-point discrimination, acupuncture and proprioception. Quantitative sensory examinations, most often using Semmes-Weinstein nylon monofilament for pressure testing.

3. Vascular examination

The most common non-invasive test is arterial Doppler ultrasound. The data is represented by absolute pressure or - index. A - index of 0.45 is considered to be the minimum value at which the wound can heal after amputation. The absolute value of the toe vascular pressure of 40 mmHg is the minimum standard for wound healing. Note that patients with atherosclerotic disease may have a false increase in pressure. Other vascular examinations include determination of skin perfusion pressure and transcutaneous oxygen partial pressure. The former is the minimum pressure required to block the refilling of the skin after it has been compressed. The latter can also be used to determine the potential for healing after amputation. A pressure of less than 20 mm Hg has a high risk of wound infection, while above 30 mm Hg indicates sufficient healing potential.

4. Laboratory inspection

Blood sugar control is very important in the care of diabetic foot. If the metabolic control of diabetes is poor, there is a higher risk of ulceration. If hemoglobin A1c (glycated hemoglobin) is elevated, the ulcer healing time is prolonged and the likelihood of recurrence increases. Changes in these indicators predict patient compliance and healing optimization. In addition, serum total protein, serum albumin, and total lymphocyte count should also be examined. The minimum value for tissue healing is: serum total protein concentration is higher than 6.2 g / dl; serum albumin level is higher than 3.5 g / dl; total lymphocyte count is greater than 1500 / mm3.

5. Imaging examination

Ordinary X-ray is a first-line diagnostic test used to evaluate stress fractures, fractures, osteolysis/bone destruction, dislocation, subluxation, and changes in the bone structure of the foot and ankle; CT is used to assess details and changes in cortical bone The effect is better, such as assessing the healing of postoperative fractures or fusions. In addition, CT can also be used to assess soft tissue diseases such as abscesses; MRI is very sensitive to soft tissue and bone tissue changes caused by various causes, such as stress fractures, abscesses, osteomyelitis or neurological joint disease. However, it is difficult to distinguish Charcot joints from osteomyelitis. Both lesions have bone marrow edema and erosion-like changes.

Differential diagnosis

diagnosis

Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.

1. Symptoms: In the early stage of the disease, the patient often has itchy skin, cold limbs, feeling dull, edema, followed by continuous numbness of the double-legged sock. Most of the pain may be reduced or disappeared, and a small number of needles appear in the affected area. Knife cuts, burning pain, increased at night or when hot, duck walking or leaning on the stick, some elderly patients with a history of severe limb ischemia, such as intermittent claudication, rest pain.

2. Signs: The patient's lower limbs and feet are dry, smooth, edematous, the hairs fall off, the lower limbs and feet become smaller, and the skin can be seen with scattered blisters of varying sizes, blemishes, ecchymoses, pigmentation, and cold extremities. When raising the lower limbs, the feet are white; when drooping, it is purple-red, toenail deformation, thickening, brittleness, shedding, muscle atrophy, poor muscle tone, common foot deformity, humeral head depression, metatarsophalangeal joint bending It has a bow-shaped toe-like toe, the toe is overextended like a claw, and the dorsal artery is cyanotic when the dorsal artery is occluded. The pulsation is very weak or disappears. Sometimes, the vascular murmur can be heard in the stenosis of the blood vessel, and the extremity feels dull and disappears. The tuning fork vibrates and the Achilles tendon is weak or disappears.

In the chronic ulcer of the foot, a round penetrating ulcer forms in the ankle and humeral head, sometimes ligament tear, small fracture, bone destruction, and Charcot joint, dry gangrene, all Feet, toes dry, smaller, skin bright, thin, reddish, there are a number of black spots in the edge of the toe, black spots, wet gangrene, redness, swelling, skin ulceration, formation Ulcers or abscesses of varying sizes and depths, skin, blood vessels, nerves, and bone tissue necrosis.

3. Clinically, according to the degree of diabetic foot lesions, it is divided into 6 grades.

Differential diagnosis

Need to be diagnosed with lower extremity vasculitis or vasculitis, lower extremity neuropathy.

True vasculitis: thromboangiitis obliterans, vascular tube inflammation is the abbreviation of thromboangiitis obliterans, is a kind of chronic occlusive disease of the middle and small arteries, and its pathological changes are medium and small arterial wall Segmental, non-suppurative inflammation with intravascular thrombosis, luminal occlusion caused by distal limb ischemia and pain, the main features of this disease are: (1) the disease mostly occurs in male young adults; (2) The limbs, especially the toes, are cold, cold, numbness and paresthesia are common early symptoms; (3) Pain is the main symptom of the disease, manifested as: 1 intermittent claudication: when the patient walks for a long distance, calf or foot Muscle numbness, soreness, pain, convulsions, weakness and other symptoms, if you continue to walk, the symptoms are aggravated, and finally forced to stop, after standing for a while, the pain is relieved quickly, you can continue to walk, but after walking, the above symptoms are repeated Now, this symptom is called intermittent claudication. It is a typical manifestation of insufficient blood supply to the lower extremity arteries. 2 Resting pain: When the arterial ischemia is severe, the pain of the affected limb is severe and persistent. The pain is still not enough at rest. It is difficult to stay through the night. And even toe ulceration infection, pain is more intense.

"Vasculitis" in the elderly: lower extremity arteriosclerosis obliterans, lower extremity arteriosclerosis obliteration is not vasculitis, it is a manifestation of systemic arteriosclerosis, is one of the common vascular diseases in the elderly, its pathological features The abdominal aorta, radial artery, femoral artery, radial artery and other large and medium-sized arteries thicken and harden, form atheromatous plaque and calcification, and secondary thrombosis, leading to narrow or occluded arterial lumen, manifested as Vasculitis is similar to the symptoms of lower limb ischemia, so it is often mistaken for vasculitis. In many cases, elderly patients have lower extremity pain, muscle aches and weakness, can not walk normally (ie intermittent claudication), etc., often thought to be bone Hyperplasia, osteoporosis, lumbar disc herniation, rheumatism, etc., took a lot of drugs for a long time, did not go to the hospital to see a specialist in time, and even some patients were delayed by the timing of the visit and forced amputation.

Diabetes foot gangrene and other gangrene identification points: gangrene is the death of tissue cells, the cause is often divided into circulating gangrene, such as atherosclerotic gangrene, embolic gangrene, thromboangiitis obliterans, Raynaud's disease, etc. Gangrene, neurotrophic gangrene, diabetic gangrene, mechanical, physical, chemical, injury and infectious gangrene, diabetic foot gangrene, from the pathological changes and the nature of gangrene, the degree is difficult to distinguish from other gangrene, Especially in middle-aged and elderly patients with atherosclerotic gangrene, it is more difficult to distinguish, but patients with diabetic foot gangrene have severe vascular disease, rapid progression of the disease, often accompanied by peripheral neuropathy and infection, and clinically It is often encountered that the gangrene of the foot does not heal for a long time, and cases of diabetes are found only during the examination. It is necessary to pay attention to the analysis of the occurrence of gangrene, whether it is accompanied by morbidity or comorbidity.

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