Factitious hyperthyroidism is higher-than-normal thyroid hormone levels in the blood that occur from taking too much thyroid hormone medicine.
The thyroid gland produces the hormones thyroxine (T4) and triiodothyronine (T3). In most cases of hyperthyroidism, the thyroid gland itself produces too much of these hormones.
Hyperthyroidism can also be caused by taking too much thyroid hormone medicine for hypothyroidism. This is called factitious hyperthyroidism. When this occurs because the prescribed dosage of hormone medicine is too high, it is called iatrogenic, or doctor-induced, hyperthyroidism.
Factitious hyperthyroidism can also occur when someone takes too much thyroid hormone on purpose. These may be people:
- Who have mental disorders such as Munchausen syndrome
- Who are trying to lose weight
- Who want to get money from the insurance company
Children may take thyroid hormone pills accidentally.
In rare cases, factitious hyperthyroidism is caused by eating meat that has thyroid gland tissue in it.
The symptoms of factitious hyperthyroidism are the same as those of hyperthyroidism caused by a thyroid gland disorder, except that:
Your health care provider will tell you to stop taking thyroid hormone. If you need to take it, your provider will reduce the dosage.
You should be re-checked in 2 to 4 weeks to be sure that the signs and symptoms are gone. This also helps to confirm the diagnosis.
People with Munchausen syndrome will need mental health treatment and follow-up.
Factitious hyperthyroidism will clear up on its own when you stop taking or lower the dosage of thyroid hormone.
When to Contact a Medical Professional
Contact your provider if you have symptoms of hyperthyroidism.
Thyroid hormone should be taken only by prescription and under the supervision of a provider.
Factitious thyrotoxicosis; Thyrotoxicosis factitia; Thyrotoxicosis medicamentosa
Davies TF, Laurberg P, Bahn RS. Hyperthyroid disorders. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology. 13th ed. Philadelphia, PA: Elsevier; 2016:chap 12.
Kopp P. Autonomously functioning thyroid nodules and other causes of thyrotoxicosis. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 85.
Review Date 5/20/2016
Updated by: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.