The thyroid is a small gland situated below the Adam's apple in the neck. The thyroid produces hormones that affect the activity of nearly every tissue of the body, from the hair and nails to the heart and brain. Diseases and conditions of the thyroid may cause enlargement of the gland, referred to as a goiter. Signs, symptoms and blood tests help determine the diagnosis and what treatment, if any, proves necessary.
Hashimoto's Thyroiditis
Hashimoto's thyroiditis is an autoimmune disorder that targets the thyroid gland. The errant attack on the thyroid gland compromises the capacity to produce thyroid hormones, causing hypothyroidism. Typical signs and symptoms include weight gain, constipation, muscle soreness, cold intolerance, facial puffiness, dry skin, brittle thinning hair and fatigue. "The Merck Manual for Healthcare Professionals" notes that many patients with Hashimoto's thyroiditis exhibit enlargement of the thyroid early in the course of the disease. Over time, the thyroid may shrink as the disease process progressively destroys the gland.
The American Association of Clinical Endocrinologists reports that Hashimoto's thyroiditis is the most prevalent thyroid disorder in the United States, affecting approximately 14 million people. The high prevalence of Hashimoto's thyroiditis makes it one of the most common causes of goiter among Americans.
Toxic Diffuse Goiter
Toxic diffuse goiter, also known as Graves' disease, is another form of autoimmune thyroid disease. In contrast to Hashimoto's disease, the antibodies produced by the immune system with toxic diffuse goiter stimulate the gland to overproduce thyroid hormones, causing hyperthyroidism.
The American Association of Clinical Endocrinologists reports that common signs and symptoms include weight loss, diarrhea, muscle weakness, hand tremor, heat intolerance, eye protrusion, thinning hair, increased heart rate, insomnia and irritability. The thyroid gland exhibits global enlargement with Graves' disease.
Simple Nontoxic Goiter
Simple nontoxic goiter, also known as euthyroid goiter, is a noncancerous enlargement of the thyroid gland with normal function and no evidence of inflammation. According to "The Merck Manual for Healthcare Professionals," simple nontoxic goiter is the most common form of thyroid enlargement.
Iodine deficiency can cause simple nontoxic goiter, although this nutrient deficiency proves rare in the United States. Certain drugs, such as lithium and amiodarone, and some foods, such as cauliflower, cabbage and broccoli, may contribute to the formation of simple nontoxic goiter. In most cases, the cause for this condition is unknown. Simple nontoxic goiters commonly present during periods associated with significant hormonal changes, including pregnancy, puberty and menopause. Global enlargement of the thyroid typically occurs.
Most people with simple nontoxic goiter do not require treatment. Rarely, profound thyroid gland enlargement may encroach on other throat structures causing discomfort. Surgical removal of a portion of the thyroid can correct the problem in this uncommon circumstance.
References
- "The Merck Manual for Healthcare Professionals": Hypothyroidism
- American Association of Clinical Endocrinologists: Hashimoto’s Thyroiditis
- National Institute of Diabetes and Digestive and Kidney Diseases: Graves' Disease
- American Association of Clinical Endocrinologists: Hyperthyroidism
- "Merck Manual for Healthcare Professionals": Simple Nontoxic Goiter
