The thyroid gland is the body’s endocrine organ, and thyroid disorders are most common in women. They can be categorized into two main types according to thyroid function: hyperthyroidism and hypothyroidism. Hyperthyroidism is a hypermetabolic syndrome caused by an excess of thyroid hormones in the blood. Diseases that lead to hyperthyroidism include diffuse goiter with hyperthyroidism, nodular goiter with hyperthyroidism, subacute thyroiditis with hyperthyroidism, chronic lymphocytic thyroiditis with hyperthyroidism, thyroid cancer with hyperthyroidism, iodine hyperthyroidism, medically induced hyperthyroidism, pituitary hyperthyroidism, and ectopic TSH secretion syndrome, Early acromegaly with hyperthyroidism, ectopic goiter with hyperthyroidism, etc. Hypothyroidism is a disease caused by insufficient synthesis and secretion of thyroid hormones. According to the cause of the disease, it can be divided into congenital hypothyroidism, acquired hypothyroidism and idiopathic hypothyroidism; according to the location of the original disease, it can be divided into primary and secondary hypothyroidism; according to the age of onset of the disease, it can be divided into cretinism (cretinism), juvenile-type hypothyroidism and adult-type hypothyroidism. Hypothyroidism is categorized according to age of onset as cretinism, juvenile hypothyroidism and adult hypothyroidism. Thyroid diseases can be divided into four major categories according to the nature of their lesions.1) Simple goiter: including endemic goiter, sporadic goiter and hyperiodine goiter.2) Thyroiditis: including acute thyroiditis, subacute thyroiditis, painless thyroiditis, chronic lymphocytic thyroiditis and invasive fibrous thyroiditis.3) Thyroid tumors: can be divided into benign and malignant thyroid tumors. Benign tumors include thyroid adenoma, hemangioma, fibroma, etc. Malignant tumors include papillary adenocarcinoma, follicular adenocarcinoma, undifferentiated carcinoma, medullary carcinoma, squamous cell carcinoma, hemangiosarcoma and fibrosarcoma. Clinically, thyroid tumors are often manifested as thyroid nodules only, so thyroid tumors and thyroid nodules are often confused with each other. In fact, nodule is only a description of the morphology, which includes tumors, cysts, normal tissue hyperplasia formed into a mass, and other disease-induced thyroid masses. Surgery proves that about 80% of single nodules are benign tumors and 20% are malignant tumors.4) Abnormal development of the thyroid gland: common diseases include thyroglossal cysts or fistulas and ectopic thyroid. Generally, the doctor can tell you whether the thyroid gland is enlarged or not and whether there is any swelling by palpation of the thyroid gland during the initial consultation. However, due to the wide variety of thyroid disorders, further tests are needed to determine the nature of the thyroid disorder, which are categorized into functional and morphologic tests. Functional tests of the thyroid gland include the following: (1) Measurement of thyroid hormones and autoantibodies: including T3, T4, free T3, free T4, thyroglobulin antibody (TGAb), thyrotropin receptor antibody (TRAb), thyroid microsomal antibody (TMAb), thyroid peroxidase antibody (TPOAb), and anti-natriuretic sodium/iodine isotropic transporter (NIS) antibody, etc. (2) Measurement of thyroglobulin (TGAb), thyroid microsomal antibody (TMAb), thyroid peroxidase antibody (TPOAb), and anti-natriuretic sodium/iodine isotropic transporter (NIS) antibody. 2) Measurement of thyroglobulin (TG) and thyroid-binding globulin (TBG). 3) Measurement of thyroid uptake of iodine-131. 4) Thyroxine suppression test and thyrotropin excitation test. Morphologic examination of the thyroid gland includes thyroid nuclear imaging (γ-photography or PET/CT), ultrasonography, CT or magnetic resonance imaging, thyroid puncture cytology, and biopsy. Each of these imaging tests has its own characteristics and advantages, and can help us understand the size of the thyroid gland, the size, number and nature of nodules or masses. At present, the most widely used technology in China is high-frequency ultrasound and color Doppler flow imaging, which can improve the detection rate and compliance rate of thyroid cancer, with a minimum diameter of 2mm-3mm, and can clearly show the internal structure of the nodule, with or without peritoneum and calcification. Although the tumor characterization still depends on the professional level of the examining doctor, ultrasound is still widely used by virtue of its practical, economical, non-radioactive and non-invasive advantages. Protecting the thyroid gland Iodine supplementation should be appropriate Whether it is the synthesis of thyroid hormones, or the regulation of the body’s normal material and energy metabolism are dependent on the normal work of the thyroid gland. “In the past, when it comes to thyroid diseases, most of them are caused by iodine deficiency. Over the years, the implementation of iodized salt, on the contrary, some areas of the thyroid-related diseases increased, suspected that may be caused by excessive iodine intake. Iodine is one of the trace elements required by the human body; more is not good and less is not good. Iodine requirement is not simply a lower limit, but also an upper limit. When there is a lack of iodine, it is easy to cause goiter, and some people with long-term illness may become malignant thyroid cancer; and when the amount of iodine exceeds the limit, it is also the cause of the high incidence of thyroid cancer. Currently, some medical doctors are conducting research on the relationship between iodine and thyroid diseases.” President Gao Ming said, “Generally speaking, residents in coastal areas can get enough iodine from their diet, and inland areas farther from the sea have iodine deficiency. Residents in coastal areas are reminded that after consuming iodized salt, they should not over-consume seafood like kelp, which is high in iodine.” Children should stay away from radiation In clinical practice, it has been found that exposure to radioactivity in the upper mediastinum or neck during childhood is a major contributing factor to thyroid cancer. This is due to the fact that radiation can cause abnormal division of thyroid cells on the one hand, leading to cancer; on the other hand, it can damage the thyroid gland and cause a decline in secretion function, causing a large amount of secretion of thyroid-stimulating hormone, which triggers cancerous changes in thyroid cells. However, it is unlikely that thyroid cancer will occur in adults after receiving radiation therapy to the neck. Danger signs of thyroid tumor 1. Thickening of the neck or lump in front of the neck, especially painless lump in front of the neck should be noticed. 2. In addition to the lump, if it is accompanied by hoarseness or choking when drinking water; dyspnea or dysphagia; radiating pain in ear, occiput and shoulder; dilatation of neck vein under pressure or eye slit and pupil shrinkage; enlargement of lymph nodes on the same side or both sides, then it should be taken more seriously.