Thyroid disease results when the thyroid gland produces too little or too much thyroid hormone. Hypothyroidism (low thyroid) is usually caused by thyroiditis (an inflammation of the thyroid gland), including a hereditary condition known as Hashimoto's thyroiditis. Hypothyroidism may also result from iodine deficiency, and occasionally a baby is born with a non-functioning thyroid gland, which can cause mental retardation if not treated. Hyperthyroidism occurs when the thyroid produces too much thyroid hormone. It may be caused by a condition called Graves disease, nodules in the thyroid, thyroiditis, or excessive iodine intake.
One of the primary functions of the thyroid gland is to manage metabolism, so symptoms of either hypo-or hyperthyroidism are related to metabolism. Common symptoms of hypothyroidism (low thyroid) include fatigue or low energy, weight gain despite a normal eating pattern, cognitive problems, dry, coarse skin and hair, excessive menstrual periods and intolerance to cold. People with hyperthyroidism (high thyroid) are more likely to report irritability and nervousness, muscle tremors or weakness, infrequent menstrual periods, weight loss, sleep problems, and sensitivity to heat.
Hypothyroidism nearly always requires treatment with medications. Hyperthyroxine (brand names Levothroid, Synthroid and others), a synthetic hormone, is the most common treatment. Medication must be taken daily and life-long treatment is required. Thyroxine and triiodothyronine, which are thyroid hormones obtained from pigs, may be used by those who prefer an alternative treatment. Although glandular extracts are also available, they are not regulated by the FDA and quality may vary.
Hyperthyroidism is more difficult to treat, as the hormone levels must be reduced, but not too much. Medications may be used to block excess hormone production. Radioactive iodine can disable the thyroid, and surgery can be used to remove part of the thyroid gland. In some cases, the treatment may actually cause hypothyroidism, which must then be managed with thyroid medication.
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