Final answer:
The most common cause of hyperthyroidism in the United States is Graves' disease, characterized by symptoms like rapid heartbeat and weight loss. Hashimoto thyroiditis is the most common cause of hypothyroidism, leading to symptoms like fatigue and cold intolerance.
Step-by-step explanation:
The student has inquired about the most common thyroid condition. Disorders of the thyroid gland can lead to an overactive thyroid, known as hyperthyroidism, or an underactive thyroid, known as hypothyroidism. Goiter is a condition where the thyroid gland is enlarged, which can be caused by iodine deficiency, tumors, excess TSH, or LATS.
In the United States, the most common cause of hyperthyroidism is Graves' disease. Patients with Graves' disease produce an excessive amount of thyroid-stimulating immunoglobulin, which can cause symptoms such as heat intolerance, rapid heartbeat, weight loss, goiter, and exophthalmia.
Hashimoto thyroiditis is the most prevalent cause of hypothyroidism in the United States. It is an autoimmune condition where the immune system attacks the thyroid gland, leading to symptoms including a goiter, cold intolerance, and fatigue, among others.