Hyperthyroidism (or "overactive thyroid gland") is the clinical syndrome caused by an excess of circulating free thyroxine (T4) or free triiodothyronine (T3), or both.

Major clinical features in humans are weight loss (often accompanied by a ravenous appetite), intolerance to heat, fatigue, weakness, hyperactivity, irritability, apathy, depression, polyuria, and sweating.

Additionally, patients may present with a variety of symptoms such as palpitations and arrhythmias (notably atrial fibrillation), shortness of breath (dyspnea), loss of libido, nausea, vomiting, and diarrhea.

In the elderly, these classical symptoms may not be present and they may present only with fatigue and weight loss leading to apathetic hyperthyroidism..

For more information about the topic Hyperthyroidism, read the full article at Wikipedia.org, or see the following related articles:

Hypothyroidism — Hypothyroidism is the disease state caused by insufficient production of thyroid hormone by the thyroid gland. There are several distinct causes for ...  > read more

Thyroid hormone — The thyroid hormones, thyroxine (T4) and triiodothyronine (T3), are tyrosine-based hormones produced by the thyroid gland. An important component in ...  > read more

Thyroid — The thyroid is one of the larger endocrine glands in the body. It is a double-lobed structure located in the neck and produces hormones, principally ...  > read more

Menopause — Menopause (also known as the "Change of life" or climacteric) is a stage of the human female reproductive cycle that occurs as the ovaries stop ...  > read more

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