Diabetes mellitus is a group of metabolic diseases characterized by hyperglycemia. Hyperglycemia, in turn, is caused by defective insulin secretion or impairment of its biological action, or both. The long-term presence of hyperglycemia in diabetes leads to chronic damage and dysfunction of various tissues, especially the eyes, kidneys, heart, blood vessels, and nerves.
Etiology
1.Genetic factors
There is significant genetic heterogeneity in both type 1 or type 2 diabetes. There is a tendency for diabetes to develop in families, and 1/4 to 1/2 of patients have a family history of diabetes. There are at least 60 clinical genetic syndromes that can be associated with diabetes. type 1 diabetes has multiple DNA loci involved in the pathogenesis, with the DQ locus polymorphism in the HLA antigen gene being the most closely related. A variety of well-defined genetic mutations have been identified in type 2 diabetes, such as insulin genes, insulin receptor genes, glucokinase genes, mitochondrial genes, etc.
2.Environmental factors
Obesity due to excessive eating and reduced physical activity is the most important environmental factor in type 2 diabetes, making individuals with genetic susceptibility to type 2 diabetes prone to develop the disease. type 1 diabetes patients have abnormal immune system, which leads to autoimmune reaction after certain viruses such as coxsackievirus, rubella virus, mumps virus, etc., and destroys insulin beta cells.
Clinical manifestations
1. Polyhydramnios, polyuria, polyphagia and wasting
Severe hyperglycemia with the typical symptoms of “three more and one less”, mostly seen in type 1 diabetes. When ketosis or ketoacidosis occurs, the symptoms of “three more and one less” are more obvious.
2. Fatigue and obesity
Most often seen in type 2 diabetes. type 2 diabetes is often preceded by obesity, and if not diagnosed in time, weight loss will gradually occur.
Examination
1.Glucose
It is the only criterion to diagnose diabetes. For those who have obvious “three more and one less” symptoms, only one abnormal blood glucose value can be diagnosed. Asymptomatic people need two abnormal blood glucose values to diagnose diabetes. Those who are suspicious need to do 75g glucose tolerance test.
2. Urine sugar
It is often positive. Urine glucose is positive when the blood glucose concentration exceeds the renal glucose threshold (160-180 mg/dL). When the renal sugar threshold is increased, even if the blood sugar reaches the diagnosis of diabetes can be negative. Therefore, urine glucose measurement is not used as a diagnostic criterion.
3.Urinary ketone body
Urine ketone body is positive in ketosis or ketoacidosis.
4.Glycosylated hemoglobin (HbA1c)
It is the product of non-enzymatic reaction of glucose and hemoglobin binding, the reaction is irreversible, and the level of HbA1c is stable, which can reflect the average blood sugar level in the 2 months before blood sampling. It is the most valuable indicator to judge the state of blood glucose control.
5.Serum glycated protein
It is the product of non-enzymatic reaction between blood glucose and serum albumin, and reflects the average blood glucose level 1~3 weeks before blood sampling.
6.Serum insulin and C-peptide level
It reflects the reserve function of pancreatic β-cells. serum insulin is normal or increased in the early stage of type 2 diabetes or obese type, and as the disease progresses, the function of pancreatic islets gradually decreases and the insulin secretion capacity decreases.
7.Blood lipid
Lipid abnormalities are common in diabetic patients and are especially evident when blood glucose is poorly controlled. It is manifested as an increase in triglyceride, total cholesterol and LDL cholesterol levels. High-density lipoprotein cholesterol levels are reduced.
8.Immune indicators
Islet cell antibodies (ICA), insulin autoantibodies (IAA) and glutamic acid decarboxylase (GAD) antibodies are three important indicators of humoral immune abnormalities in type 1 diabetes mellitus, among which GAD antibodies have a high positive rate and long duration, and are of great value for the diagnosis of type 1 diabetes mellitus. There is also a certain positive rate in the first-degree relatives of type 1 diabetes, which has the significance of predicting type 1 diabetes.
9.Urinary albumin excretion, release immunoassay or enzyme-linked method
Urinary albumin excretion can be detected sensitively, and urinary albumin is mildly elevated in early diabetic nephropathy.
Diagnosis
The diagnosis of diabetes mellitus is generally not difficult and can be confirmed by fasting blood glucose greater than or equal to 7.0 mmol/L and/or two hours after meal blood glucose greater than or equal to 11.1 mmol/L. The diagnosis of diabetes is followed by typing.
1.Type 1 diabetes
The age of onset is light, mostly <30 years old, with sudden onset, polydipsia, polyuria, polyphagia and wasting symptoms are obvious, blood glucose level is high, many patients have ketoacidosis as the first symptom, serum insulin and c-peptide level is low, ica, iaa or gad antibody may be positive. Oral medication alone is ineffective, and insulin treatment is required.
2.Type 2 diabetes
It is common in middle-aged and elderly people, with high prevalence in obese people, often accompanied by hypertension, dyslipidemia, atherosclerosis and other diseases. The diagnosis of type 2 diabetes can be confirmed only by glucose tolerance test if the onset of the disease is insidious and there are no symptoms in the early stage, or only mild weakness and thirst. Serum insulin level is normal or increased in the early stage and low in the late stage.
Differential diagnosis
1.Liver disease
Patients with cirrhosis often have abnormal glucose metabolism, typically with normal or low fasting glucose and rapidly rising postprandial glucose. Fasting blood glucose may also be elevated in patients with long duration of disease.
2.Chronic renal insufficiency
Mild abnormalities of glucose metabolism may occur.
3.Stress state
Many stressful conditions such as cardiovascular and cerebrovascular accidents, acute infection, trauma and surgery may lead to a transient increase in blood glucose, which may recover in 1 to 2 weeks after the stressful factors are eliminated.
4.A variety of endocrine diseases
Such as acromegaly, Cushing’s syndrome, hyperthyroidism, pheochromocytoma and pancreatic glucagon tumor can cause secondary diabetes, in addition to elevated blood glucose, there are other characteristic manifestations, it is not difficult to identify.
Treatment
There is no cure for diabetes mellitus, but it can be controlled by a variety of treatments. It mainly includes 5 aspects: education of diabetic patients, self-monitoring of blood sugar, diet therapy, exercise therapy and medication therapy.
(I) General treatment
1.Education
It is important to educate diabetic patients to know the basic knowledge of diabetes, establish confidence to overcome the disease, how to control diabetes, and the health benefits of good control of diabetes. Develop appropriate treatment plan according to the characteristics of each diabetic patient’s condition.
2.Self-monitoring of blood glucose
With the gradual popularization of small and fast blood glucose meters, patients can adjust the dose of hypoglycemic drugs at any time according to the blood glucose level. type 1 diabetes is monitored at least four times a day (before meals) when intensive treatment is carried out, and eight times when blood glucose is unstable (before and after three meals, before going to bed at night and at 3:00 a.m.). Fasting blood glucose should be controlled below 7,2 mmol/L, two hours after meal blood glucose less than 10 mmol/L and HbA1c less than 7% during intensive treatment. the frequency of self-monitoring blood glucose in type 2 diabetic patients can be reduced appropriately.
(II) Drug treatment
1.Oral medication
(1) Sulfonylureas
Type 2 DM patients can use sulfonylureas after diet control, exercise, weight reduction and other treatments, and the efficacy is not satisfactory. Because the glucose-lowering mechanism is mainly to stimulate insulin secretion, so the efficacy is better for those with certain pancreatic islet function. For some diabetic patients with young age of onset and not fat body shape, they also have certain efficacy in early stage. However, when using sulfonylureas in obese patients, special attention should be paid to diet control to make weight loss gradually, and it is better to combine with biguanides or α-glucosidase inhibitor hypoglycemic drugs. The following are contraindications: first, serious liver and kidney insufficiency; second, combined with serious infection, trauma and major surgery, temporary change to insulin therapy; third, diabetic ketosis, ketoacidosis, temporary change to insulin therapy; fourth, pregnant women with diabetes, gestational hyperglycemia has a teratogenic effect on the fetus, high incidence of preterm delivery and stillbirth, so strict control of blood glucose, fasting blood glucose should be controlled at 105 mg/dL (5, 8 mmol/L) or less, and 2 hours after meal blood sugar control at 120 mg/dL (6, 7 mmol/L) or less, but control of blood sugar should not use oral hypoglycemic drugs; fifth, allergic to sulfonylureas or obvious adverse reactions.
(2) Biguanide hypoglycemic drugs
The main mechanism of hypoglycemia is to increase the utilization of glucose by peripheral tissues, increase the anaerobic enzymolysis of glucose, reduce the absorption of glucose in the gastrointestinal tract and reduce body weight. ①Indications obese type 2 diabetes mellitus, unsatisfactory effect of diet alone; type 2 diabetes mellitus with sulfonylurea alone is not effective, can add biguanides; type 1 diabetes mellitus with insulin treatment is unstable, with biguanides can reduce the insulin dose; type 2 diabetes mellitus secondary failure to change to insulin treatment, can add biguanides, can reduce insulin dosage. ② contraindications serious liver, kidney, heart and lung diseases, wasting diseases, malnutrition, hypoxic diseases; diabetic ketosis, ketoacidosis; with serious infections, surgery, trauma and other stressful conditions when the suspension of bivalirudin, switch to insulin therapy; pregnancy. ③Adverse reactions one is gastrointestinal reactions. The most common, manifested as nausea, vomiting, decreased appetite, abdominal pain, diarrhea, the incidence of up to 20%. To avoid these adverse reactions, the drug should be taken during or after meals. Second, headache, dizziness, metallic taste. Third, lactic acidosis, mostly seen in long-term, large amounts of application of hypoglycemia, accompanied by hepatic and renal decompensation, hypoxic diseases, acute infections, gastrointestinal diseases, hypoglycemic tablets cause less chance of acidosis.
(3) Alpha glucosidase inhibitors
It can be used for both type 1 and type 2 diabetes, and can be combined with sulfonylurea, biguanide or insulin. (1) Voglibose is given orally immediately before meals. ②Acarbose is taken orally immediately before meals. The main adverse reactions are: abdominal pain, intestinal flatulence, diarrhea, and increased anal discharge.
(4) Insulin sensitizer
It can enhance insulin action and improve glucose metabolism. It can be used alone or in combination with sulfonylureas, biguanides or insulin. It is not suitable for those who have liver disease or cardiac insufficiency.
(5) Glinide insulin secretagogue
(1) Repaglinide is a rapid insulin secretagogue, which is taken orally immediately before meals, with each main meal and without meals. ②Naglinide is similar to Repaglinide.
2.Insulin therapy
Insulin preparations include animal insulin, human insulin and insulin analogues. They are divided into short-acting, medium-acting and long-acting insulins according to the duration of action, and have been made into mixed preparations, such as Novolin 30R and Eugenol 70/30.
(1) Type 1 diabetes
Treatment with insulin is required. Non-intensive treatment is injected 2 to 3 times a day, and intensive treatment is injected 3 to 4 times a day, or treated with insulin pump. The dose needs to be adjusted frequently.
(2) Type 2 diabetes mellitus
Those who fail to take oral hypoglycemic drugs first use the combined treatment method, by which the original dose of oral hypoglycemic drugs remains unchanged, and the medium-acting insulin or long-acting insulin analogues are injected at 10:00 pm before bedtime, generally adjusted once every 3 days, with the aim of reducing fasting blood glucose to 4,9-8,0 mmol/L. Those who fail to do so stop taking oral hypoglycemic drugs and replace them with insulin injections twice a day. The biggest adverse effect of insulin therapy is hypoglycemia.
(iii) Exercise therapy
Increasing physical activity can improve the body’s sensitivity to insulin, lower body weight, reduce the amount of body fat, enhance physical strength, and improve work ability and quality of life. The intensity and duration of exercise should be determined according to the patient’s overall health condition, and find the amount of exercise suitable for the patient and the items that the patient is interested in. Exercise can take various forms, such as walking, brisk walking, aerobics, dancing, tai chi, running, swimming, etc.
(iv) Diet therapy
Diet therapy is the basis of treatment for all types of diabetes, and some patients with mild diabetes can control their disease with diet therapy alone.
1.Total calories
The total calorie requirement should be determined according to the patient’s age, gender, height, weight, physical activity, condition and other comprehensive factors. First of all, the standard weight of each person should be calculated, which can be referred to the following formula: standard weight (kg) = height (cm) – 105 or standard weight (kg) = [height (cm) – 100] × 0, 9; the standard weight of women should be subtracted 2 kg, which can also be obtained by checking the table according to age, gender and height. After calculating the standard weight, the caloric requirement per kg of standard weight is estimated according to the daily physical activity of each person.
After calculating the daily calorie requirement based on the standard weight, adjustments should be made according to the patient’s other conditions. Children, adolescents, lactation, malnutrition, emaciation and chronic wasting diseases should increase the total calories as appropriate. Obese people should strictly limit the total calorie and fat content, and give low-calorie diet, the total calorie per day should not exceed 1500 kcal, generally it is appropriate to reduce 0.5~1.0kg per month, and then calculate the total calorie per day according to the aforementioned method when it is close to the standard weight. In addition, older people need fewer calories than younger people, and adult women need fewer calories than men.
2.Carbohydrate
Carbohydrates produce 4 kcal per gram and are the main source of calories. It is now believed that carbohydrates should account for 55% to 65% of the total calories in the diet, which can be calculated by the following formula.
According to the living habits of our people, 250～400g of staple food (rice or noodles) can be entered, and the following preliminary estimation can be made: 200～250g of staple food per day for resting people, 250～300g for light physical laborers, 300～400g for moderate physical laborers, and more than 400g for heavy physical laborers.
3.Protein
Protein produces 4 kcal per gram. It accounts for 12-15% of the total calories. The protein requirement is about 1g per kg of body weight for adults, and should be increased to 1.5~2.0g per kg of body weight for children, pregnant women, lactating women, malnourished, emaciated, and those with wasting diseases, and should be reduced to 0.8g per kg of body weight for diabetic nephropathy, and further reduced to 0.6g per kg of body weight for high quality protein if there is renal insufficiency.
4.Fat
The energy of fat is high, producing 9 kcal per gram. Animal fat mainly contains saturated fatty acids. Vegetable oil contains more unsaturated fatty acids, diabetic patients are prone to atherosclerosis, vegetable oil should be used mainly.