"Goiter" is the medical term for an enlarged thyroid. The thyroid, at the front of the neck, can become enlarged as a result of a number of things. Iodine deficiency, hyperthyroidism, hypothyroidism and nodule development are among the common goiter causes.
On a global scale, lack of iodine in the diet is the leading cause of goiters. The lack of iodine affects the production of hormones necessary for proper thyroid functioning and causes the thyroid to enlarge as it seeks out more iodine. In countries where table salt is readily available, such as the United States and other First World countries, iodine deficiency usually isn’t among the leading goiter causes.
While iodine deficiency represents the most common cause of goiter in Third World countries, autoimmune disorders and nodules within the gland represent common goiter causes in First World countries. Autoimmune disorders include hyperthyroidism and hypothyroidism. Single or multiple nodules within the thyroid can result in goiter.
Hyperthyroidism, also known as Grave’s disease, is another cause of goiter. With Grave’s disease, the thyroid enlarges in response to an overproduction of the thyroid hormone thyroxine. The overproduction of thyroxine is a result of antibodies attacking the thyroid gland.
Hashimoto’s disease, also known as hypothyroidism, is a result of too little thyroid hormone. In reaction to this underproduction, the pituitary gland begins to produce more thyroid-stimulating hormone (TSH) in an attempt to stimulate the thyroid to produce more thyroid hormone. This leads to an enlarged thyroid, or goiter.
Solid and fluid-filled lumps within the thyroid are referred to as nodules. Nodule development leads to an enlargement of the thyroid and represents another possibility among goiter causes. These nodules can develop in one or both sides of the thyroid over time. When multiple lumps form it is referred to as multinodular goiter. The existence of a single nodule is known as a solitary thyroid nodule.
Thyroid cancer represents another possible cause of goiter. Though less common than non-cancerous nodules, thyroid cancer is a possibility. Those diagnosed with thyroid cancer often experience an enlargement of just one side of the thyroid, as opposed to enlargement in both sides, as is common with benign nodules.
Some of the remaining goiter causes include pregnancy and inflammation. Pregnant women may notice an increase in the size of their thyroid as a result of an increase in human chorionic gonadotropin (HCG) during pregnancy. Enlargement of the thyroid can also result from thyroiditis, an inflammation of the thyroid.