What causes thyroiditis? What are the clinical manifestations?

Clinically, thyroiditis has various manifestations, and the causes of the disease are of particular concern to everyone. So, what causes thyroiditis?

Causes of thyroiditis:

This disease is an autoimmune disease. Most patients' serum and thyroid tissues contain antibodies against thyroid antigens, mainly thyroid globulin antibodies (TGA), thyroid microsomal antibodies (MCA), thyroid cell surface antibodies (FCA), and thyroid colloid component II (CA2). The first two have clinical practical value. The thyroid globulin antibody value in normal human serum is 1:32, rarely exceeding 1:256, and the microsomal antibody value is below 1:4; in the serum of patients with chronic lymphocytic thyroiditis, the values ​​of these two antibodies can be as high as 1:2500 and 1:640 or more, respectively. At present, the disease is caused by the destruction of immune tolerance. It can be summarized into two points. One is that the target organ causes antigenic changes for some reason, making itself "non-self" and rejected; the other is that immune active cells mutate, inhibiting T cells decrease, B cells lose inhibition and become more active, and produce excessive antibodies. When antibodies and antigens bind, the antigen-antibody complex formed covers the surface of thyroid cells, and K cells bind to it and are activated. K cells are a kind of killer lymphocytes with antibody-dependent cell-mediated immune cytotoxicity. After activation, they release cytotoxins, causing the destruction of thyroid cells.

In addition, genetic factors must also be considered for the occurrence of these immune abnormalities. Half of the siblings in the same family have significantly elevated antibody levels and multiple cases of Bridgestone disease. Moens believes that this disease may be related to DRW3 and B8 of the human leukocyte HLA system, which is a congenital defect in suppressing the function of T cells. Although there is some understanding of the pathogenesis of this disease, the cause of chronic lymphocytic thyroiditis remains to be further clarified.

Clinical manifestations of thyroiditis:

1. Hashimoto's thyroiditis

The onset is slow, and the thyroid gland is often enlarged, hard, and has clear boundaries. Some patients may have compression symptoms. There is often no special feeling in the early stage, and the thyroid function may be normal. A small number of patients may have transient hyperthyroidism in the early stage, and most cases have hypothyroidism when they are discovered. Patients often show symptoms such as fear of cold, edema, fatigue, dry skin, abdominal distension, constipation, irregular menstruation, and decreased libido.

2. Subacute thyroiditis

The typical symptom is severe thyroid pain, which usually starts on one side of the thyroid gland and quickly radiates to other parts of the gland, the base of the ear, and the jaw. It is often accompanied by general discomfort, fatigue, muscle pain, and fever. The symptoms peak within 3 to 4 days after the onset of the disease and subside within 1 week. There are also many patients who have a slow onset, more than 1 to 2 weeks, and the condition fluctuates for 3 to 6 weeks. After improvement, there may be multiple relapses within a few months. The thyroid gland may increase in size by 2 to 3 times or even larger than normal, and there is obvious tenderness when touched. Within one week after the onset of the disease, about half of the patients will have symptoms of hyperthyroidism, such as excitement, heat intolerance, palpitations, tremors and sweating; these symptoms are caused by excessive release of thyroid hormone from the thyroid gland during acute inflammation. During the course of disease regression, a small number of patients may experience swelling, constipation, fear of cold, drowsiness and other symptoms of hypothyroidism, but these symptoms do not last long and eventually the thyroid function returns to normal.