Hyperthyroidism

Excerpt

Hyperthyroidism is a common thyroid disorder. "Hyperthyroidism" defines a syndrome associated with excess thyroid hormone production. It is a common misconception that the terms thyrotoxicosis and hyperthyroidism are synonyms. The term "thyrotoxicosis" refers to a state of excess thyroid hormone exposure to tissues. Although hyperthyroidism can lead to thyrotoxicosis and can be used interchangeably, it is essential to note their differences. For the sake of simplicity, this review will cover a discussion of hyperthyroidism and thyrotoxicosis. Hyperthyroidism has multiple etiologies, clinical manifestations, and treatment modalities.

Hyperthyroidism can be overt or subclinical. Overt hyperthyroidism is defined as low or suppressed thyroid stimulating hormone (TSH) levels with elevated triiodothyronine (T3) levels and/or elevated thyroxine (T4) levels. When T3 levels are elevated with low/suppressed TSH and normal T4 levels, this is called 'T3 toxicosis'. Subclinical hyperthyroidism is low or suppressed TSH with normal T3 and T4 levels. Both overt and subclinical hyperthyroidism are associated with significant long-term complications.