Thyroid disease is a medical condition that affects the function of the thyroid gland. The thyroid gland is located at the front of the neck and produces thyroid hormones that travel through the blood to help regulate many other organs, meaning that it is an endocrine organ. These hormones normally act in the body to regulate energy use, infant development, and childhood development.
There are five general types of thyroid disease, each with their own symptoms. A person may have one or several different types at the same time. The five groups are:
Hypothyroidism (low function) caused by not having enough free thyroid hormones.
Hyperthyroidism (high function) caused by having too much free thyroid hormones.
Structural abnormalities, most commonly a goiter (enlargement of the thyroid gland).
Tumors which can be benign (not cancerous) or cancerous.
Abnormal thyroid function tests without any clinical symptoms (subclinical hypothyroidism or subclinical hyperthyroidism).