What is Hyperthyroidism?

Updated at: Apr 23, 2013
What is Hyperthyroidism?

The over production of thyroid hormones (T3 and T4) by the thyroid gland leads to hyperthyroidism.

Dr Poonam Sachdev
ThyroidWritten by: Dr Poonam SachdevPublished at: Oct 23, 2012


Hyperthyroidism is the term used to describe signs and symptoms caused because of the over production of the thyroid hormone. It is a common medical condition, which has several causes, however, most of the signs and symptoms a patient has are same regardless of the cause.

[Read: Signs of Hyperthyroidism]

The thyroid gland is present in the front part of the neck just below the Adam's apple (or the thyroid cartilage). It is a butterfly shaped gland, which has 2 lobes (the right lobe and the left lobe). The two lobes are joined by a narrow piece of tissue called isthmus.

The two different forms of thyroid hormone produced by the gland include T4 and T3. The two thyroid hormones have different number of iodine units or atoms present in the hormone. Iodine is needed for synthesis of the thyroid hormone.

  • T4—it is the thyroid hormone with four iodine units (and is abbreviated as T4). It is most abundant type of thyroid hormone in the blood.
  • T3—it has three iodine units (and is abbreviated as T3). It is the active form of the hormone in the body.

In a healthy person, the thyroid gland secretes just the right amount of two thyroid hormones (T4 and T3). Thyroid hormone is an essential hormone in the body as it affects many physiological functions and regulates many aspects of metabolism in the body. Therefore, all cells in the body are affected by an increase in the thyroid hormone, which in return increases the rate at which the cells do their functions.

What causes hyperthyroidism?

There are many causes of hyperthyroidism. Some of the common causes are:

  • Graves' diseaseIt is an autoimmune disorder in which antibodies are formed in the body that stimulate your thyroid to produce an excess of T-4. This is the most common cause of hyperthyroidism.
  • Hyper-functioning thyroid nodules (toxic adenoma, toxic multinodular goitre)—This type of hyperthyroidism is caused because of one or more adenomas in the thyroid gland that produce excess of much T-4.
  • Thyroiditis—In some cases, the thyroid gland can become inflamed for unknown reasons. Owing to the inflammation, excess thyroid hormones stored in the gland get leaked into the bloodstream resulting in hyperthyroidism.


[Read: Causes of Hyperthyroidism]


Symptoms of hyperthyroidism

Some common signs and symptoms of hyperthyroidism include:

  • unintended weight loss,
  • rapid heartbeat (tachycardia),
  • irregular heartbeat (arrhythmia) or feeling of pounding of heart (palpitations),
  • increase in appetite (but even after increase in appetite you may lose weight),
  • nervousness, anxiety and irritability,
  • sweating and feeling excessively hot,
  • changes in menstrual cycle,
  • enlargement of thyroid gland (goitre), which may appear as a swelling at the base of your neck and move with swallowing,
  • fatigue, weakness and tiredness and
  • difficulty in sleeping .


Treatment of hyperthyroidism

Currently available treatments for hyperthyroidism are effective in treating all common types of hyperthyroidism. Treatment is recommended based on your age, physical condition and the severity of your disorder. Treatment options for hyperthyroidism include

  • radioactive iodine,
  • anti-thyroid medications (such as propylthiouracil and methimazole),
  • beta blockers and
  • surgery (thyroidectomy).


Read more articles on Hyperthyroidism.



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