Chronic complications of diabetes can occur in all important organs of the body. The pathogenesis of diabetes is extremely complex and not yet fully elucidated. It is thought to be related to the interaction of Genetic predisposition, insulin resistance, hyperglycemia, oxidative stress and other factors. Oxidative stress induced by hyperglycemia is an important common mechanism, which further leads to polyol pathway activation, non-enzymatic glycation, protein kinase C (PK) activation and hexosamine pathway activation, leading to tissue injury. In addition, direct or indirect involvement in a variety of chronic complications, the development of related factors include: insulin, sex hormones, growth hormones, catecholamine, and other hormone levels abnormal; Abnormal lipid metabolism, changes in endocrine and paracrine functions of adipocytes, low-grade inflammatory state, Endothelium dysfunction, blood coagulation and abnormal activity of the fibrinolysis system, etc. . A variety of complications can occur alone or in different combinations simultaneously or sequentially. Complications may exist before diabetes is diagnosed, and some patients find diabetes as a clue to the complications. Most people with diabetes die from heart or brain arteriosclerosis or diabetic nephropathy. Compared with the non-diabetic group, the death rate from all causes is 1.5-2.7 times higher, the death rate from cardiovascular disease is 1.5-4.5 times higher, the blindness is 10 times higher, the lower limb gangrene and amputation are 20 times higher, diabetic nephropathy is the first or second cause of fatal kidney disease.
1. Macroangiopathy is associated with a higher prevalence of arteriosclerosis disease, a younger onset age, and a faster progression of the disease, compared to people without diabetes. As an important component of metabolic syndrome, the prevalence of known risk factors such as obesity, hypertension, and abnormal lipid metabolism in people with diabetes mellitus (mainly T2DM) has increased significantly in arteriosclerosis. The arteriosclerosis mainly invades the aorta, coronary artery, cerebral artery, renal artery and peripheral limb artery, causing coronary heart disease, ischemic or hemorrhagic cerebrovascular disease, renal arteriosclerosis, limb arteriosclerosis, etc. .
2. Microangiopathy refers to the capillary and microvascular network between the arterioles and venules with lumen diameter less than 100m. Microangiopathy is a specific complication of diabetes mellitus, and its typical changes are microcirculation disturbance and microvascular basement membrane thickening. The mechanism of microangiopathy is very complicated, the following aspects are involved: 1 abnormal signal transduction in cells; 2 abnormal regulation of extracellular signal molecules, such as growth factors and cytokines (most important Transforming growth factor P) , renin Angiotensinogen system (Ras) , etc. 3 local changes caused by systemic factors, such as hypertension, dyslipidemia, abnormal sympathetic nervous system activity, etc. . Microvascular lesions are found in the retina, kidney, nerve, and myocardial tissue, especially in diabetic nephropathy and retinopathy.
(1) diabetic nephropathy: common in patients with a history of more than 10 years. T1DM is the main cause of death in patients with T1DM, the severity of T2DM is next to cardiovascular and cerebrovascular diseases. There were 3 types of pathological changes: 1 nodular glomerulosclerosis, highly specific; 2 diffuse. Glomerulosclerosis, the most common type, has the greatest impact on renal function, but is less specific, and similar lesions can also be seen in diseases such as glomerulonephritis capillary and systemic lupus erythematosus; 3 exudative lesions, which are less specific, it’s also found in chronic glomerulonephritis. There was no constant correlation between the histological changes of renal biopsy and the clinical manifestations and the degree of impairment of renal function. The occurrence and development of diabetic renal damage can be divided into five stages: 1 Stage I: for the initial stage of diabetes, the renal volume increased, the human glomerular arterioles dilated, the renal plasma flow increased, the glomerular pressure increased, the glomerular filtration rate (GFR) significantly increased; 2 stage II: glomerular capillary basement membrane thickening, urinary albumin excretion rate (UAER) , mostly normal, intermittently elevated (e. g. post-exercise, stress state) , GFR slightly elevated, 3 Stage III: early nephropathy, Microalbuminuria, uA: Er continued in 20 ~ 200/~ g/min (normal < 10g =”min =”GFR =”uAER =””> 200 # TG/min, that is, urinary albumin excretion > 300 # TG/24h, equivalent to the total amount of urine protein > 0.5 g,/24h, GFR decreased, with edema and hypertension, renal function gradually decreased; 5 V: Uremia, most renal atresia, UAER decreased, serum creatinine increased, blood pressure increased. Renal Hemodynamics abnormalities are an important early feature of this disease, characterized by hyperperfusion (. Kidney plasma flow is too high) state, can promote the progress of the disease. American Diabetes Association (Amer). The ICAN Diabetes Association (Ada-RRB-(-RRB-007) recommends that screening and Microalbuminuria use albumin/creatinine ratios of less thLn 30 g/l, 30 ~L299 mg/l and L300 mg/l for immediate urine samples as normal, Microalbuminuria and massive albuminuria, respectively . .
(2) diabetic retinopathy: the course of diabetes over 10 years, most patients with varying degrees of retinopathy, is one of the main causes of blindness. Retinal changes can be divided into six stages, belonging to two broad categories. Stage I: microangioma, small hemorrhage; stage II: hard exudate; stage III: soft exudate with cotton wool. Stage I ~ III is background retinopathy. Stage IV: Neovascularization, vitreous hemorrhage; stage V: fibrovascular proliferation, vitreous organization; STAGE VI: Traction Retinal Detachment, blindness. The above IV ~ VI stage was proliferative retinopathy (PDR) . When PDR is present, it is often accompanied by diabetic nephropathy and neuropathy.
(3) other: cardiac microvascular lesions and myocardial metabolic disorders can cause extensive focal myocardial necrosis. Called diabetic cardiomyopathy, it can cause heart failure, arrhythmia, Cardiogenic shock, and sudden death. This complication can worsen outcomes in patients with diabetes and other heart disease.
3. Neurological complications can affect any part of the nervous system. It is suggested that the pathogenesis is related to macrovascular and microvascular lesions, immune mechanism and growth factor deficiency.
(1) central nervous system complications: 1 neurological changes associated with severe DKA, hyperglycemia, hyperosmolar status, or hypoglycemia; 2 ischemic stroke; 3 accelerated brain aging and increased risk of Alzheimer’s disease.
(2) peripheral neuropathy: most common, usually symmetrical, with lower extremities more severe than upper limbs and progressing more slowly. First appear limb end sensory abnormalities, can be accompanied by hyperalgesia, pain; later motor nerve may be involved, muscle weakness and even muscle atrophy and paralysis. The early hyperreflexia, the later period weakens or disappears, the tuning fork vibration feeling weakens or disappears. Electrophysiologic examination can detect sensory and motor nerve conduction velocity slowing at an early stage. The single peripheral nerve injury occurred less, mainly involving the cerebral nerve.
(3) autonomic neuropathy: also more common, and can appear earlier, affect gastrointestinal, cardiovascular, urogenital system function. I the clinical manifestation is the pupil change (reduces and the irregularity, the light reflex disappears, the adjustment reflex existence) , the perspiration is abnormal (does not have the sweat, the little perspiration or the hyperhidrosis) , the stomach empties the delay (gastroparesis) , the diarrhea (after the meal or midnight) , the constipation and so on, orthostatic hypotension, tachycardia, increased heart rate, increased residual urine volume, urinary incontinence, urinary retention, impotence and so on.
4. Diabetic foot: foot ulcers, infections, and/or deep tissue destruction associated with distal nerve abnormalities and varying degrees of peripheral vascular disease in the lower extremities. Mild cases of foot deformity, dry skin and cool hair, callus (high risk foot) , serious cases can appear foot ulcers, gangrene. Diabetic foot is the main cause of amputation and disability.
5. Other types of diabetes can cause Macula of retina disease (edema) , cataracts, glaucoma, refractive changes, iridocycliasis and other eye complications. Skin lesions are also common, some are diabetes-specific, most are non-specific, but the clinical manifestations and subjective symptoms are more severe.
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