The thyroid gland is a small organ located on the anterior face of the neck whose function is to produce hormones, which are essential in regulating the functioning of all our cells and, ultimately, our organism. It's a fundamental organ to stay alive.
In general this gland works normally, but may present deviation in the sense of hypofunction (hypothyroidism) or hyperfunction (hyperthyroidism).
In these situations we can have changes in body temperature, heart rate, blood pressure, weight, appetite, mood (even severe psychiatric changes), bowel function, and many others, often subtle and difficult to diagnose.
Hypothyroidism is the most common functional thyroid disease and reflects a deficient hormonal production. It is usually caused by primary thyroid failure, but it can also result from decreased TSH stimulation over it (central or secondary hypothyroidism).
Autoimmune thyroiditis, also called Hashimoto's thyroiditis or chronic lymphocytic thyroiditis, is the leading cause of hypothyroidism (70%) and is associated with elevated anti-thyroid antibody titers.