Hashimoto's thyroiditis

Thyroiditis is the medical term for inflammation (swelling) of the thyroid gland, which can either cause abnormally low or high levels of thyroid hormones in the blood.

The thyroid gland is a butterfly-shaped gland found in the neck. It produces hormones that are released into the bloodstream to control the body's growth and metabolism. They affect processes such as heart rate and body temperature, and help convert food into energy to keep the body going.
Symptoms vary depending on the type of thyroiditis.