糖尿病的小血管病變

Microvascular Disease In Diabetes Mellitus

糖尿病患的小血管疾病包括視網膜病變、腎臟病變與神經病變三種，它們是糖尿病特有的病變，其發生和長期暴露在高血糖有密切關連。在台灣，40歲以上非胰島素依賴型糖尿病患(Non-Insulin-Dependent Diabetes Mellitus, NIDDM)的視網膜病變盛行率為35.0%，其中背景性、前增殖性與增殖性視網膜病變盛行率分別為30.0%、2.8%與2.2%。視網膜病變的每年累積發生率為4.8%，而病情惡化與惡化為增殖性視網膜病變的累積發生率分別為7.5%與1.5%，情況比國外嚴重，主要原因是血糖控制差。視網膜病變的危險因子包括罹患糖尿病的時間長短、血糖控制的好壞、遺傳、治療方式、抽菸及高血壓，由於愈早發現，治療效果愈好，所以病患應該定期檢查。糖尿病的神經病變以周邊神經病變最常見，其中以感覺纖維最早受損，包括對溫度、輕觸與針刺的感覺，其次是振動與肌腱反射，至於運動纖維較晚受損。自律神經病變的症狀常出現在周邊神經病變之後，而副交感神經又比交感神經早受到損害，所以心臟的迷走神經最早受到影響，然後是心臟的交感神經與內臟的交感、副交感神經，嚴重時血管運動控制消失，影響因素主要是血糖控制好壞、罹病時間長短、遺傳及神經營養劑，例如維生素，最好的治療策略是積極控制血糖，預防或延緩它的發生。糖尿病腎臟病變分成五個階段：(1)腎絲球肥大期；(2)白蛋白尿正常期（靜止期）；(3)潛伏腎病變期（微白蛋白尿期）；(4)臨床腎病變期（巨白蛋白尿期）；(5)末期腎衰竭。胰島素依賴型糖尿病患(Insulin-Dependent Diabetes Mellitus, 1DDM)罹患腎臟病變的盛行率在發病20～25年時達到高峰21%，然後下降，發病40年時大約為10%。非胰島素依賴型糖尿病患罹患腎臟病變的盛行率在歐洲大約為16%，和罹病時間有密切關連，發病一年內的盛行率為5%，而發病20年以上的病患大約有35%罹患腎臟病變。胰島素依賴型糖尿病患出現微白蛋白尿時，常伴隨小血管疾病，並且是未來成為末期腎衰竭的預測因子；非胰島素依賴型糖尿病患發生微白蛋白尿時常常會伴隨高血壓與大血管疾病，並且和早期死亡有關。糖尿病腎臟病變的相關因子包括下列因素：遺傳、年齡、罹病時間長短、治療方式、血糖控制情形、血壓、小便白蛋白排出速度、抽菸、泌尿道感染與飲食中蛋白質攝取量。病患除了定期追蹤腎功能，包括檢查血液尿素氮、肌酸酐、與小便的蛋白與白蛋白流失量外，臨床上應該減少攝取蛋白質、戒菸、積極控制血糖與血壓及避免使用影響腎功能的藥物，使用降血壓的藥物最好用血管收縮素轉換酶抑制劑與鈣離子遮斷劑。

Microvascular disease in diabetes mellitus includes retinopathy, neuropathy and nephropathy. These complications of diabetes are unique to diatetic patients with long-standing hyperglycemia. In Taiwan, 3570 of diabetic patients aged 40 and over develop diabetic retinopathy, 2.8% develop pre-proliterative retinopathy and 2,2% develop proliferative retinopathy pre-proliferative retinopathy. The one-year cumulative incidence is 4.8% for background diabetic retinopathy, 7.5% for the worsening, and 1.5% for proliferative retinopathy. The main reason for the higher rates in Taiwan is poor control of the bloodglacose levels. The risk factors for diabetic retinopathy are duration of diabetes, hyperglycemia, family history, smoking, hypertension, and microalbuminuria. Peripheral neuropathy is one of the most common complication of diabetes. Sensory fibers responding temperature, light touch and pin-prick sensation are affected first, followed by sense of vibration, tendon reflex and motor fibers. Symptomatic peripheral neuropathy usually precedes the development of symptomatic automatic neuropathy. Parasympathetic dysfunction precedes sympathetic dysfunction and may involve the following processes: cardiac vagal and sympathetic denervation, splanic denervation and loss of vasomotor control. The risk factors of diabetic neuropathy are duration of diabetes, hyperglycemia, genetic predisposition, and neutrition. The best of treatment stategy is prevention by maintaining good control of blood glucose. Diabetic nephropathy (DN) is of increasing concern in Insulin-Dependent Diabetes Mellitus and Non-Insulin-Dependent Diabetes Mellitus. A new classification of staging of DN was developed by Mogensen, which includes 1) glomerular hypertrophy; 2) normal albumin excretion; 3) incipient DN or microalbuminuria; 4) overt DN or macroalbuminuria. 5) end-stage-renal-failure (ESRF). The prevalence rate of DN in IDDM was 21% in patients with more than a 22-years history of diabetes, followed by a decline to 10% after 40 years. The prevalence of DN in NIDDM was 16% in European countries, being 5% in the first year after onset, and increasing steadily with duration of diabetes to a rate of 35% in those with diabetes for more than 20 years. Microalbuminuria in IDDM was associated with disease progression to ESRF and other forms microangiopathy while it was associated with progression to overt DN, higher mortality, hypertension and macroangiopathy in NIDDM. The risk factors of DN are duration of diabetes, hyperglycemia, smoking, hypertension, frequent urinary tract infection, age, genetic factor, dietery protein, and hyperlipidemia. In the prevention of microvascular disease, good control of diabetes is the most effective intervention. Cardiovascular risk factors are also crucial.