Definition
Hyperthyroidism is an imbalance of metabolism caused by overproduction of thyroid hormone.
Alternative Names
Thyrotoxicosis; Overactive thyroid
Causes
The thyroid gland is located in the neck. It produces several hormones which control the way that every cell in the body uses energy (metabolism). The thyroid is part of the endocrine system.
Hyperthyroidism or thyrotoxicosis occurs when the thyroid releases too many of its hormones over a short (acute) or long (chronic) period of time. Many diseases and conditions can cause this problem, including:
- Graves' disease
- Non-cancerous growths of the thyroid gland or pituitary gland
- Tumors of the testes or ovaries
- Inflammation (irritation and swelling) of the thyroid due to viral infections or other causes
- Ingestion of excessive amounts of thyroid hormone
- Ingestion of excessive iodine
Graves' disease accounts for 85% of all cases of hyperthyroidism.
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