Hyperthyroidism caused by ingestion of excessive amounts of exogenous thyroid hormone.
Alternative Names
Factitious thyrotoxicosis; Thyrotoxicosis factititia; Thyrotoxicosis medicomentosa
Causes, incidence, and risk factors
The thyroid gland produces the hormones thyroxine (T4) and triiodothyronine (T3) under the control of thyroid stimulating hormone (TSH) produced by the pituitary gland. Hyperthyroidism is the clinical condition caused by too much thyroid hormone. Hyperthyroidism is caused by over production of thyroid hormone by the thyroid gland in the vast majority of cases. However, thyroid hormone preparations have been available since 1891, and ingesting too much thyroid hormone can cause hyperthyroidism. Hyperthyroidism caused by exogenous hormone is called factitious hyperthyroidism. Factitious hyperthyroidism may occur when thyroid hormone is prescribed to treat hypothyroidism and the prescribed dose is too high. However, purposeful and usually secretive ingestion of thyroid hormone has been discovered among patients with psychiatric illness (usually people with a medical background), patients attempting to lose weight, and individuals attempting to receive insurance compensation. Children may occasionally require treatment for accidental ingestion of thyroid hormone pills. In rare instances, factitious hyperthyroidism has been found to be caused by ingestion of meat contaminated with thyroid gland tissue.
Treatment
Exogenous thyroid hormone is stopped. Patients need to be reevaluated in 2 to 4 weeks to make sure that signs and symptoms of hyperthyroidism have resolved (this also helps to confirm the diagnosis).
Expectations (prognosis)
Hyperthyroidism will resolve when exogenous thyroid hormone is stopped or, in the case of prescribed thyroid hormone, the dose is lowered. Patients taking thyroid hormone for secondary gain may be difficult to treat.
Complications
If factitious hyperthyroidism is long-standing, patients are at risk for the complications of untreated hyperthyroidism caused by the thyroid gland. See the article on hyperthyroidism for a complete review. Some complications include:
Irregular heart rhythm (atrial fibrillation) Chest pain (angina) Heart attack Loss of bone mass (if severe, osteoporosis) Weight loss
Calling your health care provider
Contact your health care provider if symptoms of hyperthyroidism occur.
Prevention
Thyroid hormone should be taken only by prescription and under the supervision of a licensed physician.