chronic autoimmune thyroiditis
Introduction
Introduction to chronic autoimmune thyroiditis Chronic autoimmune thyroiditis (chronic autoimmunethyroiditis) is also known as chronic lymphocytic thyroiditis, Hashimoto's thyroiditis (Hashimoto'sthyroiditis), Hashimoto's disease. More common in middle-aged women, long course, slow onset, thyroid is diffuse, mild to moderate swelling, tough texture, more asymptomatic, less common pain, occasionally mild pain or tenderness, seen in the formation of goiter Fast, anti-thyroid antibody titers are significantly higher. There may be pharyngeal discomfort, and local symptoms caused by thyroid enlargement are rare, such as neck pressure and difficulty in swallowing. No cervical lymphadenopathy. basic knowledge The proportion of illness: 0.001% Susceptible people: more common in middle-aged women Mode of infection: non-infectious Complications: thyroid cancer lymphoma gland lymphoma diabetes edema
Cause
Causes of chronic autoimmune thyroiditis
(1) Causes of the disease
Hashimoto's thyroiditis is an organ-specific autoimmune disease, and its etiology is very complicated. It may have genetic factors interacting with environmental factors and the coordination of age, sex hormones, etc., causing disease, the disease has a family aggregation phenomenon, the thyroid itself The production of antibodies is related to autosomal dominant inheritance.
(two) pathogenesis
In terms of genetic factors, the most concerned about the relationship between HLA-II genes and diseases, especially the role of DQ sites, studies have shown that HLA-DR molecules are not directly related to disease, the correlation may be Because there is a high degree of linkage disequilibrium between DR and DQ, and the primary related factors are often specific alleles of DQ locus, foreign studies on HLA genetic factors found that white and white DBW3, DR5 increased, while Japanese The frequency of DBW53 is high. Domestic research data indicate that HLA-DQAI*0301 gene is associated with susceptibility to HT.
Recent studies have shown that apoptosis is closely related to the pathogenesis of Hashimoto's thyroiditis, and lymphocyte infiltration may be involved in the occurrence and development of apoptosis. Hashimoto's thyroiditis thyroid follicular cells express Fas and FasL in high infiltration. The expression of FasL on lymphocytes is very weak, so the up-regulation of Fas and FasL on the thyroid tissue of Hashimoto's thyroiditis will lead to their suicide. On the other hand, the weak expression of FasL on infiltrating lymphocytes suggests The role of cytotoxic T lymphocytes (CTLs) in the pathogenesis of Hashimoto's thyroiditis may not directly kill thyroid follicles through its expression of FasL, but by releasing certain cytokines (such as IL-1, IL-2, IFN-, IFN-, etc. up-regulate the expression of Fas and FasL in thyroid cells, causing apoptosis.
Prevention
Chronic autoimmune thyroiditis prevention
Avoid using iodine-containing drugs for women with a history of this disease, so as not to induce hypothyroidism. When the woman is pregnant, avoid excessive iodine intake, so as to prevent iodine from passing through the placenta, resulting in increased fetal TSH and neonatal thyroid. Hypofunction.
Complication
Chronic autoimmune thyroiditis complications Complications thyroid cancer lymphoma gland lymphoma diabetes edema
Hashimoto's disease with thyroid cancer: Hashimoto's thyroiditis can be combined with papillary thyroid carcinoma, follicular carcinoma, metaplastic and non-Hodgkin's lymphoma, medullary thyroid carcinoma is rare, Hashimoto's disease, the incidence of thyroid cancer It does not increase, however, the incidence of thyroid lymphoma is increased. In a group of 95 surgically treated HTs in China, 6 cases (6.3%) with concurrent thyroid cancer were found, and 5 cases of HT surgery were found in our hospital. Cases of thyroid cancer, this phenomenon may be due to the occurrence of HT and tumors are related to immune defects, in the following situations to be vigilant:
1 The thyroid enlargement is obviously increased or the thyroid gland does not shrink or even increase after thyroid hormone treatment.
2 local lymph node enlargement or compression symptoms.
3 hoarse voice.
4 thyroid pain is more obvious and persists, and the treatment is invalid.
5 There is a single nodule in the thyroid gland, the quality is hard, and the cold nodules can be seen in the scan. We have found 2 cases of patients with significant thyroid enlargement with moderate fever in the clinic. After the operation, the disease was confirmed as Hashimoto's thyroiditis. In addition, Hashimoto's thyroiditis may also be associated with silent thyroiditis, localized sputum mucinous edema, infiltrative exophthalmos or autoimmune polyendocrine syndrome type II (Addison disease, AITD, type I diabetes, hypogonadism One of the manifestations of the disease.
Symptom
Chronic autoimmune thyroid symptoms common symptoms dysphagia goiter cervix lymphadenopathy nodular goiter toxemia
More common in middle-aged women, long course of disease, slow onset, thyroid gland diffuse, mild to moderate swelling, tough texture, more asymptomatic, less common pain, occasionally mild pain or tenderness, seen in the formation of goiter Fast, anti-thyroid antibody titers are significantly elevated, may have pharyngeal discomfort, local symptoms caused by thyroid enlargement are rare, such as neck pressure, difficulty swallowing, etc., no cervical lymphadenopathy.
Goiter is characteristic: diffuse goiter, or multinodular goiter, rare single nodule, if the thyroid gland is a single nodule, it is the only remaining thyroid tissue due to thyroid tissue destruction It is not a true single nodule, it can be asymmetrical, the texture is tough, the surface is often not smooth, and it has a rounded protrusion. It is often one of the characteristics of the cone leaf, which can move up and down with swallowing.
Examine
Examination of chronic autoimmune thyroiditis
1. ESR can be elevated; 2-globulin and -globulin and immunoglobulin, anti-nuclear antibodies are also often elevated.
2. Blood lipids accompanied by hypothyroidism, elevated serum total cholesterol and low-density lipoprotein cholesterol, may also be accompanied by a decrease in high-density lipoprotein cholesterol and an increase in triglyceride levels.
3. The thyroid iodine rate is normal, decreased or increased; depends on residual thyroid function and TSH levels.
4. Potassium perchlorate release test 50% ~ 75% positive, suggesting iodine organic disorders.
5. Plasma protein-bound iodine (PBI) is increased, often not proportional to T4.
6. The thyroid function depends on the degree of lymphocytic infiltration and follicular cell proliferation. The early general function is normal, and some TSH has been elevated to maintain a normal normal serum thyroid hormone concentration, but TSH is overreactive to TRH administration. This indicates the presence of subclinical thyroid dysfunction, with T3 and T4 decreasing with further destruction of the thyroid gland.
7. Thyroid autoantibody TGAb, TPOAb is present in the blood circulation with high titer. TPOAb is more common than TGAb, and the titer is higher and lasts longer. The typical chronic lymphocytic thyroiditis in young patients can only contain low titer antibody. , RIA double antibody method is often >50%, enzyme-linked immunosorbent assay (ELISA) and enzyme immunoassay (EIA) method, 60% ~ 66% of patients with chronic lymphocytic thyroiditis TGAb positive, TPOAb positive 80% ~ 95% However, there is no significant increase in long-term disease. Most patients with atrophic thyroiditis have a longer course. 80% of thyroid autoantibodies are not detected, and other thyroid autoantibodies can be slightly elevated. The positive rate of TSAb is 14.2%. Significantly increased, TSBAb positive rate was 37.7%.
8. Cytokine IL-4 has good reproducibility and specificity, is not affected by other IL, hormone, lactic acid, etc., increased in chronic lymphocytic thyroiditis, decreased after treatment, untreated chronic lymphocytic thyroiditis patients IL-8 levels are increased.
9. Due to increased release of iodine protein, Tg in the blood can be increased.
10. Other hormones such as calcitonin (CT) levels are lower in patients with atrophy, with more obvious hypothyroidism. Patients with chronic lymphocytic thyroiditis have significantly increased 42.4% PRL levels in hypothyroidism, of which nearly 1/ 5 PRL levels > 60 mg / L.
Other auxiliary inspections:
1. Radionuclide examination, generally suspected of this disease, does not require nuclear examination, generally manifested as thyroid enlargement, iodine distribution is uneven or "cold", "cold" nodules change, due to lack of specificity, It is difficult to distinguish from other thyroid diseases, the loss of local iodine accumulation, and the part that marks severe thyroid disease. The MIBI scan shows that "cold nodules" can basically exclude malignant nodules, while high MIBI intake may differentiate follicular thyroid cancer. Very great, the second diagnosis combined with MIBI scan after 99mTc scan can improve the diagnosis rate of malignant nodules by 7.8 times. 201Tl scan has the characteristics of high sensitivity and low specificity, and it is not superior to the identification of benign and malignant thyroid nodules. Sex.
2. Ultrasound examination is not high, diffuse or nodular thyroid enlargement, 18% to 95% with diffuse hypoechoic, 3mm nodules can be found with 10MHz high frequency.
3. Pathological examination of thyroid fine needle or thick needle is helpful for patients with uncertain clinical diagnosis and "cold nodule" with isotope examination, especially for patients with positive autoantibodies to avoid unnecessary surgical treatment, for chronic lymphocytes In thyroiditis, the correct rate of the first fine needle aspiration cytology was 92%. The accuracy of fine needle aspiration cytology for the identification of benign and malignant nodules was 85.9%, and the high grade of primary thyroid malignancy Lymphoma has a diagnostic possibility, but it is difficult to diagnose low-grade malignant lymphoma due to the lack of atypical nuclear features. It is difficult to identify cytological examinations for proliferating follicular cell nodules and follicular adenomas. Need a thick needle or even an open biopsy.
4. The use of flow cytometry or immuno-type -cell-specific monoclonal antibodies helps to determine the number of lymphocytes cloned and suggests the diagnosis of lymphoma. Recently, semi-quantitative needle biopsy-reverse transcription (RT) has been used. The PCR (ABRP) technique was used to detect the success of monoclonal Ig heavy chain mRNA in the diagnosis of thyroid malignant lymphoma. The diagnostic specificity was 100% and the sensitivity was 44.4%.
Diagnosis
Diagnosis and diagnosis of chronic autoimmune thyroiditis
diagnosis
Middle-aged women are diffuse, painless, and hard goiter. The disease should be considered first. The thyroid autoantibodies (TG-Ab, TPO-Ab) and TSH assays can often be diagnosed. The antibody titer is high and lasting, positive. The rate is 59% in TG-Ab and 95% in TPO-Ab. The simultaneous determination of the complementary results can reach 98%-100%. If the titer is high, it has great significance for diagnosis. Of course, antibody titer. Low or negative can not rule out the disease, such as combined needle aspiration cytology to confirm the diagnosis rate is higher.
Differential diagnosis
Chronic lymphocytic thyroiditis is generally not difficult to diagnose. The causes of misdiagnosis may be: atypical symptoms, single or multiple nodules in the thyroid gland, and other thyroid disorders, lack of specific diagnostic methods and the disease Lack of full awareness and so on.
1. Thyroid cancer and thyroid malignant lymphoma The thyroid gland rapidly (2 to 3 months) progressive enlargement, fixation, hard, adhesion to surrounding tissues, accompanied by compression symptoms such as hoarseness (recurrent laryngeal nerve compression), cervical lymphadenopathy Large, if necessary, give appropriate amount of thyroid hormone diagnosis and treatment for more than 4 weeks, the thyroid gland does not shrink or continue to increase asymmetry should be highly suspected of cancer, imaging such as ultrasound or radionuclide scan: cancer is mostly isolated nodules, chronic lymphocytic Thyroiditis shows heterogeneous diffuse lesions. Open thyroid biopsy can diagnose most patients. Needle aspiration cytology has diagnostic value for a small number of patients.
2. Non-toxic goiter non-toxic nodular or diffuse goiter is difficult to distinguish from this disease, but the former is softer, most of the thyroid function is normal, the diagnosis depends on thyroid antibody determination, if necessary, fine needle aspiration cytology It is clear that adolescent goiter may be more difficult to distinguish clinically from this disease, so chronic lymphocytic thyroiditis in the age group has less high titer circulating thyroid autoantibodies.
3. Others are bloated, pale and easily misdiagnosed as chronic nephritis, anemia, etc., need to improve the vigilance of this disease.
