A goiter is an abnormally large thyroid gland. A goiter develops either because the whole gland is swollen or the gland has multiple growths or nodules on it. While some people with a goiter have no symptoms, others may have symptoms of an overactive or underactive thyroid.
- Hyperthyroidism is the medical term for an overactive thyroid, which produces too much thyroid hormone. Symptoms may include: Anxiety, rapid heart rate, diarrhea, weight loss.
- Hypothyroidism refers to an underactive thyroid, which products too little thyroid hormone. Symptoms may include: Depression, fatigue, constipation, weight gain.
Causes of goiters include:
- Iodine deficiency — A goiter may be caused by not getting enough iodine through the foods you eat. However, it is rare in the United States, because table salt is supplemented with iodine.
- Graves’ disease — This autoimmune disorder causes hyperthyroidism. Grave’s disease causes the body to produce a protein called thyroid-stimulating immunoglobulin that mistakenly attacks the thyroid, causing it to overproduce thyroid hormones and swell in size.
- Hashimoto’s disease — This is another autoimmune disorder in which antibodies damage thyroid cells, leaving fewer cells to produce thyroid hormones. The pituitary gland, which controls your thyroid, stimulates the thyroid to produce more hormones, making the thyroid swell. Hashimoto’s disease is the most common cause of hypothyroidism.
- Thyroid nodules — Nodules are overgrowths of tissue that may overproduce thyroid hormone or many not cause any symptoms. Rarely, nodules may contain cancer cells.
- Thyroiditis — This condition is an inflammation of the cells in the thyroid that may cause the thyroid to produce too much or too little thyroid hormone.
- Thyroid cancer — Cancerous cells may grow in nodules on the thyroid.