Hypothyroidism

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Hypothyroidism facts

  • Hypothyroidism refers to any state in which thyroid hormone production is below normal.
  • There are many disorders that result in hypothyroidism.
  • The thyroid gland is regulated by another gland that is located in the brain, the pituitary.
  • Hypothyroidism is a very common condition.
  • The symptoms of hypothyroidism are often subtle, but can include increased cholesterol levels, depression, and fatigue.
  • A blood test is used to confirm hypothyroidism.
  • With the exception of certain conditions, the treatment of hypothyroidism requires life-long medication.

What is hypothyroidism?

Hypothyroidism is a condition characterized by abnormally low thyroid hormone production. There are many disorders that result in hypothyroidism. These disorders may directly or indirectly involve the thyroid gland. Because thyroid hormone affects growth, development, and many cellular processes, inadequate thyroid hormone has widespread consequences for the body.

This article will focus specifically on hypothyroidism in adults.

What are thyroid hormones?

Thyroid hormones are produced by the thyroid gland. This gland is located in the lower part of the neck, below the Adam's apple. The gland wraps around the windpipe (trachea) and has a shape that is similar to a butterfly - formed by two wings (lobes) and attached by a middle part (isthmus).

The thyroid gland uses iodine (mostly available from the diet in foods such as seafood, bread, and salt) to produce thyroid hormones. The two most important thyroid hormones are thyroxine (T4) and triiodothyronine (T3), which account for 99% and 1% of thyroid hormones present in the blood respectively. However, the hormone with the most biological activity is T3. Once released from the thyroid gland into the blood, a large amount of T4 is converted into T3 - the active hormone that affects the metabolism of cells.

Thyroid Gland illustration - Hypothyroidism
Thyroid Gland illustration - Hypothyroidism

Medically Reviewed by a Doctor on 10/9/2013

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Hypothyroidism Symptoms

Symptoms of hypothyroidism can be mild or severe, but are often very subtle. People with a mild form of the condition may not have any symptoms at all. The most serious form of hypothyroidism is called myxedema, which can lead to coma and even death. An underactive thyroid gland affects all organs and functions within the body, leading to both physical and emotional symptoms. Some of the most common symptoms of hypothyroidism in adults are:...

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