Diabetes (DM) is a group of metabolic diseases characterized by chronic hyperglycemia caused by multiple causes, which is caused by the deficiency of insulin secretion and/or action. Its typical symptoms are “three more and one less”, namely polyuria, excessive drinking, excessive eating, and weight loss, which may be accompanied by skin itching. Long term metabolic disorders of carbohydrates, fats, and proteins can also lead to various chronic complications, such as chronic progressive lesions, functional decline, and failure of tissues and organs such as the eyes, kidneys, nerves, heart, and blood vessels; Acute and severe metabolic disorder may occur in severe condition or stress, such as diabetes ketoacidosis (DKA), hypertonic hyperglycemia syndrome.
Clinical classification
At present, the classification standard (1999) proposed by WHO diabetes Expert Committee is commonly used internationally.
- Type 1 diabetes (T1DM)
(1) Immune-mediated (1A): acute and delayed types.
(2) Idiopathic (1B): No evidence of autoimmunity.
- Type 2 diabetes (T2DM)
From mainly insulin resistance accompanied by progressive insulin secretion deficiency to mainly insulin progressive secretion deficiency accompanied by insulin resistance.
- Other special types of diabetes
It refers to some high blood glucose states with relatively clear etiology at different levels (from environmental factors to genetic factors or the interaction between the two).
(1) Genetic defects in pancreatic beta cell function
It includes adult onset diabetes (MODY) and mitochondrial gene mutation diabetes in young people.
(2) Genetic defects in insulin action
It includes type A insulin resistance, goblin face syndrome, Rabson Mendenhall syndrome, fat atrophic diabetes, etc.
(3) Pancreatic exocrine diseases
Including pancreatitis, trauma/pancreatectomy, pancreatic tumors, pancreatic cystic fibrosis, hemochromatosis, fibrocalcified pancreatic disease, etc.
(4) Endocrine disorders
Including acromegaly, Cushing’s syndrome, glucagon tumor, pheochromocytoma, hyperthyroidism, somatostatin tumor, aldosterone tumor, and others.
(5) Diabetes caused by drugs or chemicals
Medications or chemicals that can cause hyperglycemia include Vacor (N-3-pyridyl-N-P-nitrophenylurea), pentamidine, niacin, glucocorticoids, thyroid hormones, diazepines, beta adrenergic agonists, thiazide diuretics, phenytoin sodium, alpha interferon, etc.
(6) Infection
The infectious diseases that lead to hyperglycemia include congenital rubella, cytomegalovirus infection, etc.
(7) Unusual immune-mediated diabetes
Stiff man syndrome, anti insulin receptor antibodies, and others.
(8) Other genetic syndromes related to diabetes
Down syndrome, Klinefelter syndrome, Turner syndrome, Wolfram syndrome, Friedreich ataxia, Huntington’s disease, Laurence Moon Beidel syndrome, myotonic dystrophy, porphyria, Prader Willi syndrome, and others.
- Gestational diabetes mellitus (GDM)
It refers to abnormal glucose metabolism to different degrees during pregnancy, excluding patients who have been diagnosed or suffered from diabetes before pregnancy, which is called diabetes complicated pregnancy. GDM is mainly related to hormonal changes during pregnancy, usually occurring in the middle and late stages of pregnancy, with only mild asymptomatic hyperglycemia. Generally, the blood sugar of GDM women can return to normal after delivery, but the risk of T2DM will increase significantly in the future, so GDM patients should be screened for diabetes 4~12 weeks after delivery and followed up for a long time.
epidemiology
contagious
Non infectious.
incidence rate
In 2013, the prevalence of diabetes in China was 10.9%.
Easy to reach people
Type 1 diabetes can occur at any age, but it is most common before the age of 30. Type 2 diabetes is more common in adults, and usually starts after the age of 40.
Easy to develop areas
T1DM is rare in Asia, but its incidence rate is high in some countries and regions; It is estimated that T1DM accounts for less than 5% of diabetes in China.
cause of disease
executive summary
The etiology and pathogenesis of diabetes are extremely complex and have not yet been fully clarified. Different types of diabetes have different causes, and environmental factors play an important role in the pathogenesis.
underlying cause
- Related causes
(1) Type 1 diabetes
The vast majority are autoimmune diseases, with genetic and environmental factors jointly involved in their onset. Environmental factors mainly include viral infections, chemical toxins, and dietary factors.
(2) Type 2 diabetes
It is also caused by the combined effects of genetic and environmental factors. Environmental factors include aging, modern lifestyle, overnutrition, lack of physical activity, uterine environment, stress, chemical toxins, etc.
- Pathogenesis mechanism
(1) Type 1 diabetes
Some external factors (such as virus infection, chemical poisons, diet, etc.) act on individuals with genetic susceptibility, activate a series of autoimmune reactions mediated by T lymphocytes, cause selective islet beta cell destruction and functional failure, and the insulin secretion in the body is insufficient and progressive, eventually leading to diabetes. In recent years, it has been confirmed that with the increase of the incidence rate of overweight and obesity in children and adolescents, some T1DM patients also have insulin resistance, which also plays a role in the pathogenesis of T1DM and (or) accelerating the deterioration of the disease.
(2) Type 2 diabetes
The dysfunction of beta cells leads to varying degrees of insulin deficiency and tissue (especially skeletal muscle and liver) insulin resistance, which are the two main links in the onset of T2DM. Insulin resistance refers to the reduced sensitivity of target organs (mainly liver, muscle, and adipose tissue) to insulin action. At the same time, there may also be issues such as abnormal function of pancreatic alpha cells and defects in the secretion of enteropancreatin.
Risk factors
- History of impaired glucose regulation (IGR).
- Age ≥ 45 years old.
- Overweight or obesity.
- First degree relatives of T2DM.
- There is a history of huge child production or GDM.
- Polycystic ovary syndrome, long-term treatment with antidepressant drugs, etc.
symptom
executive summary
Early symptoms often manifest as metabolic disorders, mainly characterized by “three more and one less”, namely polyuria, excessive drinking, excessive eating, and weight loss. Many patients have no symptoms and only discover high blood sugar during health checks or laboratory tests for various diseases. In the late stage, chronic complications mainly occur in tissues and organs such as the eyes, kidneys, nerves, heart, and blood vessels.
Typical Symptoms
- Drink and urinate frequently
After an increase in blood sugar, osmotic diuresis can cause polyuria, leading to thirst and excessive drinking.
- Eat more
Patients often have symptoms such as easy hunger and overeating.
- Weight loss
Peripheral tissues have impaired glucose utilization, increased fat breakdown, negative protein metabolism balance, gradually showing weakness and weight loss, and hindered growth and development in children.
- Blurred vision
If blood sugar rises rapidly, it can cause changes in aqueous humor and lens osmotic pressure, leading to refractive changes and blurred vision.
Accompanied Symptoms
Some patients may have skin itching, especially itching in the external genitalia.
complication
- Acute severe metabolic disorder
(1) Diabetes ketoacidosis (DKA)
Diabetes is the most common emergency. The main manifestations are hyperglycemia, ketosis, and acidosis, which are severe metabolic disorders caused by the combined action of insulin deficiency and excessive antagonistic insulin hormones. Specifically, it can manifest as fatigue, vomiting, headache, a smell of rotten apples in the breath, and in severe cases, consciousness disorders and coma may occur. For patients with early ketosis, only sufficient insulin and fluid supplementation should be given, the condition should be closely monitored, blood glucose and ketones should be checked regularly, and insulin dosage should be adjusted; Once diagnosed, patients with acidosis or even coma should be actively rescued immediately.
(2) Hyperosmotic Hyperglycemia Syndrome (HHS)
Characterized by severe hyperglycemia, high plasma osmotic pressure, and dehydration, patients may have varying degrees of consciousness disorders or coma, and some patients may also have ketosis. This disease is mainly seen in elderly T2DM patients, with a slow onset. Initially, it presents as polyuria, polydipsia, and decreased appetite, gradually leading to severe dehydration and neurological symptoms. Patients have slow reactions, irritability or apathy, drowsiness, and gradually fall into coma. In the late stage, they may experience oliguria or even urinary obstruction. The treatment principle is to replenish fluids as soon as possible to restore blood volume, correct dehydration, lower blood sugar, correct electrolyte and acid-base balance disorders, while actively seeking and eliminating causes, preventing and treating complications, and reducing mortality.
- Infectious diseases
Diabetes is easy to be complicated with various infections, and those with poor blood sugar control are more likely to occur and more serious. Pyelonephritis and cystitis are more common in female patients and are prone to recurrent attacks. In severe cases, they can lead to renal and perirenal abscesses, as well as necrosis of the renal papilla. Purulent skin infections such as boils and abscesses can occur repeatedly, sometimes leading to sepsis or sepsis. Fungal skin infections such as tinea pedis and tinea corporis are also common. Fungal vaginitis and balanoposthitis are common complications in female patients, mostly caused by Candida albicans infection. The incidence of diabetes complicated with pulmonary tuberculosis was significantly higher.
- Chronic complications
(1) Diabetes nephropathy
It is the main cause of death for TIDM patients. It can manifest as symptoms such as hypertension, proteinuria, and renal dysfunction.
(2) Diabetes ophthalmopathy
Diabetes patients with a course of more than 10 years often have retinopathy of varying degrees, which is one of the main causes of blindness.
(3) Diabetes cardiomyopathy
Diabetes can cause cardiac microvascular disease and myocardial metabolic disorder, leading to extensive focal necrosis of myocardium, and inducing heart failure, arrhythmia, cardiogenic shock and sudden death.
(4) Neurological complications
Complications of the central nervous system, accompanied by changes in consciousness resulting from severe DKA hyperosmolar hyperglycemia or hypoglycemia; Ischemic stroke; Accelerated brain aging and senile dementia. The common types of peripheral neuropathy include distal symmetric polyneuropathy, focal mononeuropathy, asymmetric multiple focal neuropathy, and multiple radiculopathy (diabetes muscular atrophy). Autonomic neuropathy, clinically manifested as delayed gastric emptying (gastroparesis), diarrhea (after meals or midnight), constipation, etc; Resting tachycardia, orthostatic hypotension, silent myocardial ischemia, QT interval prolongation, and in severe cases, sudden cardiac death may occur; Increased residual urine volume, urinary incontinence, urinary retention, etc; Other conditions include erectile dysfunction, changes in pupils (shrinking and irregular, disappearance of light reflex, presence of regulatory reflex), and abnormal sweating.
(5) Diabetes foot
It refers to foot ulcer, infection and (or) deep tissue destruction related to nerve abnormalities at the distal end of the lower limb and peripheral vascular diseases of different degrees. It is one of the most serious chronic complications of diabetes and the most expensive treatment, and is the main reason for non traumatic amputation of diabetes. Mild cases may present with foot deformities, dry and cold skin, and calluses (high-risk feet); Severe cases may lead to foot ulcers and gangrene.
(6) Other
The prevalence of atherosclerosis in diabetes patients is high; Periodontal disease is the most common oral complication of diabetes; Skin lesions are also common, some are specific to diabetes, and most are nonspecific. The prevalence of some cancers in diabetes patients, such as breast cancer, pancreatic cancer, bladder cancer, is increasing. In addition, depression, anxiety, and cognitive impairment are also common.