Gangrene of the foot

Introduction Diabetic foot lesions refer to: Insufficient blood supply due to vascular disease in diabetic patients, and loss of foot due to neuropathy and infection with foot changes. Patients who have amputated for diabetic foot disease are 5 to 10 times more likely than non-diabetics. In fact, similar pathological changes can occur in other parts of the body, except that the incidence of foot lesions is significantly higher than in other areas. The main manifestations of diabetic foot are lower extremity pain and skin ulcers. From light to heavy, it can be intermittent claudication, lower limb rest pain and foot gangrene. In the early stage of the disease, the physical examination can detect the lack of blood supply to the lower limbs. For example, when the lower limbs are raised, the skin of the feet is pale, and when the lower limbs sag, it is purple-red. The feet are cold, and the dorsal artery pulsation weakens and disappears. Intermittent claudication is when the patient sometimes walks and suddenly feels pain in the lower extremities, and has to walk limping. Rest pain is the result of further development of lower extremity vascular disease. Not only does the lower limbs supply insufficient blood when walking, but also the lower limbs are painful because of blood. In severe cases, patients can sleep at night. The disease develops further, and the lower limbs, especially the feet, can be necrotic, and the wounds are unhealed for a long time. In severe cases, they have to amputated to the disabled.

Cause

The cause of diabetic foot is multifactorial. Diabetic neuropathy, peripheral vascular disease and microcirculatory disorder are the main causes, which may exist alone or in combination with other factors, such as foot structural malformation, abnormal gait, skin or toenail. Malformations, trauma and infection are also important causes of diabetic foot.

Diabetic vasculopathy and neuropathy are the basic causes of diabetic foot complication. Diabetic people's feet are particularly prone to vascular and neuropathy. Diabetic vascular and neuropathy affect each other and cause a series of clinical foot diseases, including toe disease and spasm formation. , skin damage and foot ulcers, musculoskeletal lesions cause foot deformation. People with diabetes are prone to trauma due to neuropathy, which often leads to loss or reduction of the foot. Mild trauma can quickly lead to ulcers, infections and gangrene, which eventually necessitates amputation. The incidence of diabetic foot is significantly increased, which is related to the following factors:

1 The increase in the number of patients with diabetes worldwide;

2 The life expectancy of diabetes is prolonged, and the duration of diabetes is also prolonged;

3 The increase in the aging population. The prevalence of diabetic foot varies from country to country, accounting for 6% to 12% of hospitalized diabetics. In the United States, there are more than 40,000 diabetic amputees per year. In fact, 50% of non-traumatic amputees are diabetics, and diabetics have lower extremity amputations. The risk is 15 times that of non-diabetics.

an examination

Related inspection

Blood sugar skin elasticity check skin color EMG

In addition to the clinical manifestations, it is necessary to do some other tests:

1, laboratory tests for diabetes such as urine sugar, blood sugar, oral glucose tolerance test.

2, ischemic examination

(1) Lower limb position test In the diabetic foot patients, the skin of the foot was obviously pale after 30-60 seconds of raising the lower limbs, and the middle part was purple-red after the limb was drooping. If the filling time of the vein (the time when the skin of the foot turns from pallor to rosy) is more than 15 seconds, the blood supply to the lower limb is obviously insufficient.

(2) The palpation of the lower extremity arteries can palpate the national artery and the dorsal artery in the national fossa (the fossa behind the knee joint) and the dorsal foot. Patients with diabetic foot may have arterial pulsation weakened or even disappeared.

(3) Limb blood flow map can understand limb blood supply and blood vessel elasticity, but its accuracy is not good.

(4) Ultrasound examination is commonly used by color Doppler (Dappler) to check the femoral artery, the arteriovenous vein and the dorsal artery. It can be directly observed and can be quantitatively positioned and analyzed. It has good perceptuality, heterogeneity and accuracy, and it is a non-invasive examination method.

(5) angiography can understand the extent of vascular lesions in the lower extremities, blood flow distribution and the presence or absence of collateral circulation. However, this method is a traumatic examination, which will aggravate the arterial spasm and make the limbs insufficiency. It is generally only used for the positioning examination before the limb surgery.

3, microcirculation examination is generally through the living microscope to directly observe the microcirculation changes of fingernail wrinkles in diabetic patients, microcirculation abnormalities often suggest microvascular lesions.

4, electrophysiological examination using nerve conduction velocity EMG examination, early detection of diabetic peripheral neuropathy. Diabetic peripheral neuropathy is an important risk factor for diabetic foot.

5, X-ray examination can be found in the arterial wall calcification, osteoporosis and destruction, osteomyelitis and bone and joint disease, etc., generally as a routine examination.

Diabetic foot is a serious threat to health, and early detection and timely treatment are very important. Partial skin water occurs in diabetic patients.

Differential diagnosis

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

True vasculitis: thromboangiitis obliterans, vascular inflammation is the abbreviation of thromboangiitis obliterans, is a chronic obstructive disease of the middle and small arteries of the extremities, and its pathological changes are the wall of the small and medium arteries. 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 occurs mostly in male young adults;

(2) The limbs, especially the toes, are cold, chills, numbness and paresthesia are common early symptoms;

(3) Pain is the main symptom of this disease, which is expressed as:

1 Intermittent claudication: When the patient walks for a long distance, the calf or foot muscles develop numbness, soreness, pain, convulsions, weakness and other symptoms. If you continue walking, the symptoms will be aggravated, and finally you will be forced to stop. After standing and resting for a while, The pain is relieved quickly and can continue to walk, but the above symptoms reappear after walking. This symptom is called intermittent claudication and 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 sustained. The pain is still not enough at rest, and it is difficult to sleep at night. Even the toe rupture and infection, the pain is more severe.

"Vasculitis" in the elderly: lower extremity arteriosclerosis obliterans, lower extremity arteriosclerosis obliteration is not vasculitis, it is a manifestation of systemic arteriosclerosis, and is one of the common vascular diseases in middle and old age. The pathological features of the abdominal aorta, radial artery, femoral artery, and arterial artery and other large intima thickening and hardening, the formation of atheromatous plaque and calcification, and secondary thrombosis, leading to narrow or occluded arterial lumen, It is manifested as a lower limb ischemia symptom similar to vasculitis, so it is often mistaken for vasculitis. Many middle-aged and elderly patients have lower extremity pain, muscle aches and weakness, unable to walk normally (ie, intermittent claudication), and often think that it is bone hyperplasia, osteoporosis, lumbar disc herniation, rheumatism, etc., taking a lot of drugs. After a long time of treatment, he did not go to the hospital to see a specialist in time, and some patients were forced to amputate because of the delay in the time of the visit.

The key points for the identification of diabetic foot gangrene and other gangrene: gangrene is the death of tissue cells. The etiology is often divided into circulating gangrene, such as atherosclerotic gangrene, embolic gangrene, thromboangiitis obliterans, gangrene caused by Raynaud's disease, neurotrophic gangrene, diabetic gangrene, mechanical, physical, Chemical, injury and infectious gangrene. Diabetic foot gangrene, the pathological changes and the nature and extent of gangrene are difficult to distinguish from other gangrene. Especially in middle-aged and elderly patients with diabetes, atherosclerotic gangrene is more difficult to distinguish. However, patients with diabetic foot gangrene have severe vascular disease, and the lesion progresses rapidly, often accompanied by peripheral neuropathy and infection. In the clinic, it is often encountered that the gangrene of the foot does not heal for a long time, and the case of diabetes is found only when the examination. Attention should be paid to the analysis of the occurrence of gangrene, whether it is associated with morbidity or comorbidities.

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