The thyroid is a butterfly-shaped gland in the front of the neck. Its primary function is to produce the hormones triiodothyronine (T3) and thyroxine (T4), which help regulate metabolism and aid in brain development, digestive function, muscle control, and mood regulation.
When the thyroid produces either too much or too little of these hormones, it causes the gland to work inefficiently, leading to disorders such as hyperthyroidism and hypothyroidism, the two most common types of thyroid disease. Other thyroid-related conditions include thyroiditis, thyroid nodules, goiter, and thyroid cancer.
Certain autoimmune thyroid diseases, such as Hashimoto’s disease and Graves' disease, can be hereditary. Other risk factors for thyroid diseases include being female, having another autoimmune disease, pregnancy, and more.
Symptoms of thyroid disease depend on whether too much or too little thyroid hormone is being produced. Symptoms of hypothyroidism (low hormone levels) include fatigue, weight gain, hair loss, and feeling cold. Symptoms of hyperthyroidism (high hormone levels) include weight loss, rapid heart beat, and insomnia. Symptoms of other forms of thyroid disease can include a swollen neck, among others.
The causes are varied. Autoimmune diseases such as Grave’s disease and Hashimoto’s disease cause the thyroid to produce too much or too little thyroid hormone. Pregnancy can also result in an under- or overactive thyroid. Other causes of thyroid disease include thyroiditis, radioactive iodine treatment, and possibly radiation for head and neck cancers.
People with hyperthyroidism often experience weight loss. The more severe the hyperthyroidism, the greater the weight loss. Weight loss can also occur with other conditions that involve an excess of thyroid hormone, such as thyroiditis.
An abnormally enlarged thyroid gland that often causes a visible and palpable lump in the neck. A goiter can be caused by an excess of thyroid-stimulating hormone (TSH), thyroid nodules, inflammation of the thyroid, or thyroid cancer.
Chemicals produced in the body that affect various processes and systems. The thyroid gland produces the hormones triiodothyronine (T3) and thyroxine (T4). When these hormone levels are too high (hyperthyroidism) or too low (hypothyroidism), the pituitary gland sends more or less thyroid stimulating hormone (TSH) to the thyroid to help balance the levels.
A condition resulting from a thyroid that is underactive, and therefore unable to produce sufficient levels of thyroid hormone. In some cases, hypothyroidism is caused by treatments used to address other thyroid conditions. If you are hypothyroid, your doctor will prescribe a thyroid replacement medication.
High-energy rays of radiation that are targeted to specific points on your body, which destroys or slows the growth of cancer cells; it is usually administered for a short period of time five days a week. Radiation may be used to treat medullary or anaplastic thyroid cancer, or other types of thyroid cancer that don’t respond to radioactive iodine treatment.
A treatment commonly used to treat hyperthyroidism or Graves’ disease. The radioactive iodine is given in a single dose and is taken orally as a liquid or in a capsule.
The iodine enters the thyroid, damaging and killing the thyroid cells present in any part of the body. This shrinks the thyroid, slows down its function, and reverses hyperthyroidism.
American Thyroid Association. Thyroid and Weight.