Factitious hyperthyroidism
Key points
- Factitious hyperthyroidism involves high levels of thyroid activity caused by ingestion of excessive amounts of thyroid hormone.
- The thyroid gland produces the hormones thyroxine (T4) and triiodothyronine (T3).
- If thyroid hormone supplementation is medically necessary, the dosage must be reduced.
- Factitious hyperthyroidism will clear up on its own when thyroid hormone ingestion is stopped or the prescribed dose is lowered.
Alternative names
Factitious thyrotoxicosis; Thyrotoxicosis factititia; Thyrotoxicosis medicomentosa
Definition
Factitious hyperthyroidism involves high levels of thyroid activity caused by ingestion of excessive amounts of thyroid hormone.
Causes, incidence, and risk factors
The thyroid gland produces the hormones thyroxine (T4) and triiodothyronine (T3). Hyperthyroidism is the clinical condition which results from excessive levels of these hormones, which can be caused in a number of ways.
In the vast majority of cases, hyperthyroidism is caused by overproduction of thyroid hormones by the thyroid gland itself. In some other cases, the pituitary gland produces too much thyroid-stimulating hormone (TSH).
Thyroid hormone preparations have been available as medications since 1891 and are used to treat hypothyroidism. Ingesting too much thyroid hormone medication can also cause hyperthyroidism. Hyperthyroidism caused by taking too much of this hormone is called factitious hyperthyroidism.
Factitious hyperthyroidism may occur when thyroid hormone is prescribed to treat hypothyroidism and the prescribed dose is too high.
It can also occur when a person intentionally takes an excessive amount of thyroid hormone; people with psychiatric disorders such as Munchausen syndrome deliberately (and usually secretively) take these hormones.
Patients attempting to lose weight and individuals fraudulently seeking to receive insurance compensation also sometimes misuse thyroid hormone and induce this condition. Children may occasionally require treatment for accidental ingestion of thyroid hormone pills.
In rare cases, factitious hyperthyroidism has been found to be caused by ingestion of meat contaminated with thyroid gland tissue.
Symptoms
Symptoms of factitious hyperthyroidism are identical to the symptoms of hyperthyroidism caused by the thyroid gland, with the following exceptions:
- There is no goiter. The thyroid gland is usually small.
- The eyes do not protrude, as in ophthalmopathy of Graves' disease.
- Thickening of the skin over the does not occur, as it occasionally does with Graves' disease.
Signs and tests
- TSH (low)
- Total T4 (high)
- Free T4 (high)
- Total T3 (high)
Written and revised by
Gerald Hurowitz, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
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