The thyroid is a butterfly-shaped gland in front of the neck that is responsible for producing the hormones thyroxine and triiodothyronine, which regulate the body's metabolism. When the thyroid becomes enlarged, this is sometimes referred to as a "goiter." Existence of a goiter may not indicate that the thyroid gland is functioning improperly, but it indicate a more serious health condition, such as a thyroid disorder or even cancer. People may find an enlarged thyroid to be painful or uncomfortable. An enlarged thyroid can cause changes in vocal quality, restrict the airway and may result in choking on certain foods and liquids. There are several common medical conditions that can lead to an enlarged thyroid.
Graves' disease is a form of hyperthyroidism with an autoimmune component. The antibodies in the immune system mistakenly view the thyroid as an "enemy" and launch an attack. This results in the gland becoming overly stimulated, causing it to produce excess amounts of thyroid hormone. The gland becomes exacerbated, and a goiter will form.
Like Graves' disease, Hashimoto's disease is also an autoimmune disorder. However, patients with this condition exhibit hypothyroidism as the disease-ravaged gland cannot produce adequate amounts of thyroid hormone. Nevertheless, the pituitary gland continues to send thyroid-stimulating hormone to the thyroid, exacerbating it and causing it to become enlarged.
Thyroid Nodules & Solitary Nodules
An enlarged thyroid gland can be the result of multiple solid or fluid-filled nodules that grow on both lobes of the thyroid or a single nodule that grows on only one side of the thyroid. In most cases, the nodules are benign and do not have the potential to develop into cancer.
Cancer of the Thyroid
Far less common than thyroid nodules is cancer of the thyroid. This type of enlargement usually occurs in only one side of the thyroid gland.
Thyroiditis is an inflammation of the thyroid that can be caused by an underlying health condition or sometimes after pregnancy. Some forms of thyroiditis are caused by bacterial infections, although these are extremely rare. Although thyroiditis can occur in conjunction with Hashimito's and Graves' diseases, it is generally transient in nature.
Deficiency in Iodine
The "fuel" the thyroid needs to produce hormones is iodine. Because iodine is added to table salt and many other foods, those living in first-world countries will almost never experience an enlarged thyroid because of a lack of iodine in their diets. However, a goiter is more problematic in developing countries where access to iodine-rich foods and sea salt is limited.