simple goiter
Introduction
Introduction to simple goiter Simple goiter is caused by iodine deficiency, iodine excess, thyroid material or congenital defects, leading to thyroid hormone production disorders or increased demand, resulting in relatively insufficient thyroid hormone, increased secretion of TSH in the pituitary gland to cause thyroid compensatory enlargement, But not accompanied by abnormal thyroid function. The enlarged thyroid tissue is followed by irregular hyperplasia and regeneration, and the nodules are called nodular goiter, which is divided into endemic and sporadic goiter. Simple goiter is a goiter with normal thyroid function. It is a compensated goiter caused by iodine deficiency, thyroid mass or related enzyme defects. It is not accompanied by obvious hyperthyroidism or diminished thyroid function. It is called non-toxic goiter, which is characterized by excretion in the endemic area of non-endemic goiter, without tumor and inflammation. The thyroid gland is diffusely enlarged at the beginning of the disease, and can develop multi-nodular enlargement later. basic knowledge The proportion of illness: 0.025% Susceptible people: no specific people Mode of infection: non-infectious Complications: endemic goiter
Cause
Cause of simple goiter
Lack of iodine (40%):
In the mountainous areas far away from the sea in China, such as Yunnan-Guizhou Plateau and Shaanxi, Shanxi, Ningxia and other places, because the soil iodized salt in the mountainous area is washed away, and the food and drinking water contain insufficient iodine, there are many people who have this disease. For "endemic goiter", in the absence of raw material "iodine", and the thyroid function still needs to maintain normal needs, the secretion of thyroid stimulating hormone in the anterior pituitary is increased, thus causing compensatory enlargement of the thyroid gland.
Increase in hormone levels (20%):
During puberty, pregnancy, lactation and menopause, the body's metabolism is strong, the demand for thyroid hormones increases, causing excessive secretion of thyroid stimulating hormone for a long period of time, and can also promote goiter, which is a kind of swelling. Physiological phenomena, often shrinking by themselves after adult or pregnancy lactation.
Thyroid hormone synthesis disorder (20%):
Some simple goiters occur due to a certain obstacle in the process of biosynthesis and secretion of glandular hormones. For example, peroxyacid salts, sulphates, nitrates, etc. in thyroid substances can interfere with thyroid uptake of inorganic iodides. : Sulfonamides, thiourea and vegetables containing thioureas (radish, cabbage) can prevent the synthesis of thyroid hormones, thereby causing a decrease in blood thyroid hormones, thus enhancing the anterior pituitary thyroid stimulating The secretion of hormones promotes thyroid enlargement. Similarly, the lack of congenital defects of recessive inheritance, such as peroxidase or proteolytic enzymes, can also cause thyroid hormone biosynthesis or secretion disorders, causing goiter.
Pathogenesis
In recent years, a new understanding of the mechanism of simple goiter has emerged, that is, there may be a thyroid growth immunoglobulin (TCI) in this patient, which has TSH-like stimulation of thyroid growth, but no TSH or IgG-like Can promote the role of thyroid function variability, therefore, patients without hyperthyroidism, this autoimmune mechanism caused by simple goiter patients and their relatives may have other autoimmune diseases, when the goiter is too large to do surgery After resection, the goiter is prone to recurrence and has been found clinically, and the detailed mechanism remains to be studied.
Catz reported that about 21.7% of patients with nodular goiter may be associated with Hashimoto's disease. Tianjin Medical University reported 552 cases of nodular goiter. There may be 45 cases with varying degrees of thyroiditis (8.2%). There were 14 cases of diffuse inflammation, 30 cases of focal inflammation, and 1 case of granulomatous inflammation, which was significantly higher than endemic goiter complicated with thyroiditis. This nodular goiter may have cellular immunity or thyroid autoregulation. As a result, there was no significant difference in serum TSH and thyroid-free patients with simple diffuse goiter, suggesting that diffuse goiter does not depend on elevated serum TSH levels, and serum TSH in nodular goiter is more diffuse. Low and no enlargement, indicating that the thyroid function of nodular goiter is autonomously regulated, hypothalamic-pituitary-thyroid axis function study found that 61% of TRH stimulation test, its TSH response is lower than normal, thyroid function T3 and T4 are normal levels, and the T3 and T4 levels of a few patients may be increased or decreased.
Prevention
Simple goiter prevention
1. For residents with endemic goiter epidemic areas, collective prevention should be done. In the iodine-deficient area, it is most effective and convenient to use iodized salt. The concentration is generally 1:10000. The lipiodol muscle injection is suitable for infants and young children. The formation of iodine storage, the absorption is very slow, the effect is better than iodized salt, <1 year old, with 125mg (including iodine), 1 to 4 years old 250mg, 5 to 9 years old 750mg, > 10 years old 1000mg.
2, 40 years of age or older, especially in patients with nodular goiter, should avoid eating too much iodine-containing substances, so as to avoid iodine hyperthyroidism.
Sporadic high-iodine goiter, try to avoid the use of iodine or reduce the amount of their use for close observation and follow-up, should also pay attention to pregnant women with iodine, to avoid neonatal iodine-induced goiter, and even suffocation death, local high iodine Sexual goiter should filter and adsorb water and food to reduce the amount of iodine.
Iodine-deficient scattered goiter should be added with iodine salt, ie, sodium iodide or potassium iodide in salt, more than 1:10000 (0.01%), 150-200g of iodine per day has been used for prevention, iodine used in countries around the world. The salt content varies, depending on the specific requirements. It is usually in the range of 1:100,000 to 10,000 (0.001% to 0.01%). In recent years, the domestic application of lipiodol injection has been used to prevent and treat it. One-time injection of 1.5ml of iodized oil (containing 1000mg of iodine) can maintain the curative effect for 5 years, the thyroid can be significantly reduced, the child needs more than the adult (calculated by kilogram body weight), about 1 year old is 125mg iodine content, 2 ~ 4 The age is 250mg containing iodine, 5-9 years old is 750mg iodine content, the age of 10 years old can reach 900~1000mg iodine content, because iodized oil is absorbed very slowly in the body, should be followed up every year after use, observe the effect.
China has a vast territory and different terrain. There are high-iodine areas in the inland areas such as Xiaoyi County of Shanxi Province, which can coexist with inland iodine deficiency. Coastal high iodine areas such as Rizhao County of Shandong Province can coexist with iodine deficiency in mountainous areas. The phenomenon of mutual neighboring, and therefore can not be unified with iodine prevention, because it is unfavorable for patients with high iodine goiter, easy to cause hyperthyroidism, should cause attention, prevention and treatment of goiter must be investigated separately in each province and city, after obtaining basic data for analysis Different treatment can effectively prevent sporadic simple goiter and endemic goiter.
Complication
Simple goiter complications Complications endemic goiter
Excessively swollen thyroid may compress the trachea, causing difficulty in breathing or even suffocation. The prevalence of infants with endemic goiter in the endemic area or mothers with sporadic simple goiter is higher, so it should be based on prevention. Reduce the birth rate of disabled children.
Symptom
Simple goiter symptoms Common symptoms Thyroid gland and smooth... Goiter hoarseness nausea thyroid enlargement Dysphagia
Early simple goiter has no obvious symptoms, often found by others to have mild to moderate thyroid gland, most of the goiter in adolescence, pregnancy and lactation, slow onset, diffuse enlargement of goiter, soft , no vascular murmur, no tremor, no hyperthyroidism or hypothyroidism, late stage gradually developed a huge goiter, and can have nodules of varying sizes, nodular goiter, while having a sac sexy and hard feeling, gland Varicose veins can be seen outside, in some patients, because of the huge goiter can cause compression symptoms, such as cough, hoarseness, poor breathing, difficulty swallowing or nausea, vomiting, etc., the thyroid gland behind the sternum can still cause the superior vena cava Compression syndrome, when there is thyroid cyst hemorrhage, the patient has sudden pain in the thyroid area, acute thyroid enlargement, B-ultrasound can find the bleeding area, the goiter of this disease can be between I° and II° in the early stage, later It can be above III°. When there is a huge nodular goiter in the late stage, the gland of the patient can be swollen like the size of the head, and the sag before the sternum often affects Bowing, turning and labor, there may be malignant changes in the giant nodular goiter in the advanced stage, and the thyroid function may also be mutated, and hyperthyroidism or hypothyroidism may occur.
1, more common in endemic goiter endemic areas, long course, can be several years or ten years.
2, there are diffuse enlargement of bilateral thyroid, and then there are single or multiple nodules of different sizes in the thyroid (one or both sides).
3, nodular texture is soft or soft, smooth, with swallowing up and down movement, slow growth, generally less compression symptoms, post-sternal goiter can have head and neck venous return disorder symptoms, cystic changes in the nodules, short-term It grows rapidly and there is pain.
4, thyroid function is generally normal.
5, some patients with hyperthyroidism, a small number of cancer can occur, the performance of the recent rapid growth of the mass, and malignant changes.
Examine
Simple goiter examination
1, serum TSH, T3, T4 detection: serum TSH, T3, T4 levels in patients with simple goiter.
2. 131I uptake rate: 131I uptake rate is normal or elevated.
3, serum TPOAb, TgAb: generally negative, a small number may be mildly elevated, may suggest that it is more likely to have hypothyroidism in the future.
4, fine needle aspiration cytology: for the B-ultrasound showed a low echo of the solid nodules, calcified nodules 1mm diameter nodules, texture hard nodules or rapid growth nodules should be fine needle aspiration cytology Examination, fine needle aspiration cytology is the most effective method for preoperative evaluation of benign and malignant thyroid nodules, with sensitivity ranging from 65% to 98% and specificity ranging from 72% to 100%.
5, neck X-ray examination: for patients with longer course, thyroid enlargement or respiratory obstruction symptoms or retrosternal goiter, should take tracheal X-ray to understand the presence or absence of tracheal displacement, tracheal softening, and can judge the sternum The location and size of the posterior goiter.
6, neck ultrasound: neck B-ultrasound is a convenient and reliable method for the diagnosis of goiter. B-ultrasound can detect small nodules of 2 to 4 mm. Therefore, B-ultrasound can detect nodules that are not touched by physical examination. Usually, the incidence of adult thyroid nodules is found to be 4% to 7%, while B-ultrasound found that adults are close. 70% have thyroid nodules. When color Doppler examination, it can be found that the normal thyroid blood flow signal does not increase significantly, showing a small amount of blood flow signal.
7. Radionuclide imaging: Radionuclide imaging can evaluate the function of thyroid morphology and thyroid nodules. In diffuse goiter, the thyroid gland is enlarged, the radioactivity is evenly distributed, and the nodular goiter can be seen with hot nodules or cold nodules.
8. CT and MRI of the neck: CT or MRI of the neck does not provide more information than B-mode ultrasound and the price is higher, but it has a higher diagnostic value for retrosternal goiter.
9, respiratory function test: giant goiter or retrosternal goiter should be tested for lung function to make a functional evaluation of airway pressure.
Diagnosis
Diagnosis and diagnosis of simple goiter
Residents of non-endemic goiter areas, diffuse thyroid enlargement or nodular enlargement, exclude hyperthyroidism, hypothyroidism, Hashimoto's goiter, acute thyroiditis, subacute thyroiditis, painless thyroiditis, thyroid After cancer and other diseases, it can be diagnosed as simple goiter based on medical history, clinical symptoms and laboratory examination data. Diagnosis of non-toxic goiter must confirm that thyroid function is normal and serum T3 and T4 levels are normal. Thyroid function status is sometimes clinically difficult to evaluate because some hyperthyroidism patients, especially the elderly, have mild or atypical clinical manifestations.
In the case of simple goiter nodules, the scan shows cold nodules, which can be misdiagnosed as subacute thyroiditis, thyroid cancer, should be used for thyroid acupuncture biopsy, in addition to Hashimoto's thyroiditis, the latter often thyroid ball Protein antibodies and microsomal antibodies were significantly increased.
Mainly should be distinguished from hyperthyroidism. In addition to goiter, hyperthyroidism has obvious hyperthyroidism symptoms, and thyroid function changes are more prominent, that is, there are obvious T3, T4, FT3, FT4, rT3 elevation and TSH decline, TRAb, TSI, TGA can be positive, TMA is more positive, 131I iodine absorption rate increases, urinary iodine increases, but simple goiter and neurosis, the differential diagnosis is slightly difficult, such as the rate of 131I increased. At this time, the T3 inhibition test can be helpful. When the simple goiter has cystic changes and hemorrhage, it should be differentiated from subacute thyroiditis. The degree of thyroid enlargement of subacute thyroiditis is not as simple as that of simple thyroid gland. Short is helpful for differential diagnosis. Mild hypothyroidism may be associated with simple hypothyroidism. In the later stage, multiple nodules may be associated with hyperthyroidism, and there are many autonomic changes, and should be differentiated from Hashimoto's disease. Diagnosis can only be identified by TGA, TMA and pathological anatomical changes, and it should be differentiated from thyroid cancer when there is a huge nodular goiter in the later stage.
