How does hyperthyroidism cause?

Cause

Hyperthyroidism is caused by overactive thyroid function and increased synthesis and secretion of thyroid hormone by itself. There are many causes of hyperthyroidism, and the mechanisms are also different. Disease factors such as Graves' disease, thyroid nodules, and thyroid tumors, as well as intake of foods or drugs containing large amounts of iodine, may cause hyperthyroidism.

Basic cause

Under normal circumstances, the thyroid hormone produced and secreted by the body's own thyroid can meet the body's needs. When the thyroid itself produces too much thyroid hormone, hyperthyroidism occurs. There are many causes of hyperthyroidism, the most common is Graves disease. Others include multinodular toxic goiter, autonomous thyroid adenoma, sporadic or familial non-autoimmune hyperthyroidism, iodine hyperthyroidism, human chorionic gonadotropin (HCG) related hyperthyroidism, pituitary thyroid-stimulating hormone (TSH) hyperthyroidism and neonatal hyperthyroidism, etc.

Diffuse toxic goiter

Also known as Graves disease (GD for short), the specific antibody produced in the body of this type of patient-Thyroid Stimulating Hormone Receptor Antibody (TRAb), leads to the proliferation of thyroid cells and excessive production of thyroid hormone, which leads to hyperthyroidism. This is the most common cause of hyperthyroidism, accounting for about 80% of all hyperthyroidism.

Multinodular toxic goiter

It is also called toxic multinodular goiter. This type of condition is caused by "out of control" in the production of thyroid hormones, excessive secretion of thyroid hormones, resulting in hyperthyroidism. It occurs mostly in elderly people in iodine-deficient areas, with more women than men.

Autonomous thyroid nodule/adenoma

About 5% of hyperthyroidism is caused by the disease, most of which are caused by gene mutations in thyroid cells that form nodules or adenomas, and can synthesize thyroid hormones autonomously. When this "autonomous" synthetic thyroid hormone is excessive, it will cause hyperthyroidism. It is more common in people around 30-40 years old.

Iodine hyperthyroidism

This is hyperthyroidism associated with increased iodine intake. Hyperthyroidism induced by excessive iodine intake in the short-term (such as taking iodine supplements or iodine-containing drugs) and people who have been exposed to iodine-deficient environments for a long time often occur in patients with nodular goiter.

Sporadic or familial non-autoimmune hyperthyroidism

It is a rare cause. The main reason is that the germline mutation of thyroid stimulating hormone receptor (TSHR) occurs, and the activity of thyroid stimulating hormone receptor (TSHR) after the mutation increases, which promotes the proliferation of thyroid cells and the synthesis of thyroid hormone, thereby causing hyperthyroidism.

Human chorionic gonadotropin (hCG)-related hyperthyroidism

hCG and TSH have the same α subunit, similar β subunit and receptor. hCG has a mild stimulatory effect on the TSH receptor of thyroid cells. After some women become pregnant, the placenta produces a large amount of hCG, which can promote the excessive production of thyroid hormone by the thyroid gland.

In addition, trophoblast cell diseases such as testicular cancer and hydatidiform mole can also produce large amounts of hCG, leading to increased thyroid hormone synthesis.

Pituitary TSH adenoma

Pituitary TSH adenoma refers to some benign tumors of the pituitary gland that can secrete a large amount of TSH, leading to goiter and excessive thyroid hormone, which can lead to hyperthyroidism.

Fetal/Newborn Hyperthyroidism

This disease is mainly caused by the mother's Graves disease during pregnancy, and the mother's thyroid-stimulating hormone receptor antibody (TRAb) enters the fetus through the placenta, resulting in fetal/newborn hyperthyroidism.

Predisposing factors

Family or genetic factors

It has been reported that 1/4 to 1/5 of hyperthyroidism patients have their close relatives also suffering from the disease, perhaps the same living environment and genetic background are related to their familial nature.

female

Estrogen in women can up-regulate the thyroid-stimulating hormone-releasing hormone (TRH) receptors of pituitary cells, promote the secretion of TSH, and induce hyperthyroidism.

History of autoimmune disease

Autoimmune diseases can induce hyperthyroidism.

Intense mental stimulation

Some patients have a history of obvious mental stimulation or trauma, such as worry, sadness, and panic before the appearance of clinical symptoms. Vigorous mental stimulation can make the thyroid function abnormal, and the reduced adrenal cortex hormone can not effectively inhibit thyroid secretion, which leads to the occurrence of hyperthyroidism.