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Clinical assessment and systemic manifestations of thyrotoxicosis 

Clinical assessment and systemic manifestations of thyrotoxicosis
Clinical assessment and systemic manifestations of thyrotoxicosis

Claudio Marcocci

, Filomena Cetani

, and Aldo Pinchera

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date: 17 May 2022

The term thyrotoxicosis refers to the clinical syndrome that results when the serum concentrations of free thyroxine, free triiodothyronine, or both, are high. The term hyperthyroidism is used to mean sustained increases in thyroid hormone biosynthesis and secretion by the thyroid gland; Graves’ disease is the most common example of this. Occasionally, thyrotoxicosis may be due to other causes such as destructive thyroiditis, excessive ingestion of thyroid hormones, or excessive secretion of thyroid hormones from ectopic sites; in these cases there is no overproduction of hormone by thyrocytes and, strictly speaking, no hyperthyroidism. The various causes of thyrotoxicosis are listed in Chapter 3.3.5. The clinical features depend on the severity and the duration of the disease, the age of the patient, the presence or absence of extrathyroidal manifestations, and the specific disorder producing the thyrotoxicosis. Older patients have fewer symptoms and signs of sympathetic activation, such as tremor, hyperactivity, and anxiety, and more symptoms and signs of cardiovascular dysfunction, such as atrial fibrillation and dyspnoea. Rarely a patient with ‘apathetic’ hyperthyroidism will lack almost all of the usual clinical manifestations of thyrotoxicosis (1).

Almost all organ systems in the body are affected by thyroid hormone excess, and the high levels of circulating thyroid hormones are responsible for most of the systemic effects observed in these patients (Table However, some of the signs and symptoms prominent in Graves’ disease reflect extrathyroidal immunological processes rather than the excessive levels of thyroid hormones produced by the thyroid gland (Table

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