It is estimated 200 million people in the world have some form of thyroid condition. One in every three Canadians has a thyroid disorder. Of those, as many as 50 per cent are undiagnosed. Most thyroid disorders are five to seven times more common in women.
Thyroid hormones are produced in the thyroid gland from iodine and an amino acid, tyrosine. The normal function of the thyroid gland is to produce and secrete hormones. There are two hormones which are closely related: T3 (triiodothyronine) and T4 (thyroxine).
These hormones have enormous impact on our health, affecting all aspects of our metabolism. They maintain the rate at which our body uses fats and carbohydrates, help control our body temperature, influence our heart rate, and help regulate the production of protein. These hormones are important for normal growth and development of children.
Problems with the thyroid can be caused by iodine deficiency and autoimmune diseases, in which the immune system attacks the thyroid, leading either to hyperthyroidism (Graves’ disease) or hypothyroidism (Hashimoto’s disease).
Graves’ disease – overactive thyroid
This condition was first described by Caleb Parry in 1786, but the pathogenesis of thyroid disease was not discovered until later. Parry was an Anglo-Welsh physician credited with one of the earliest descriptions of the exophthalmic (bulging eyeballs) goiter, published in 1825.
Now the condition is known as Graves’ disease. It is named after Robert J. Graves, an Irish physician who described it in 1835. Graves’ disease is an autoimmune disease characterized by hyperthyroidism (over active thyroid gland). We don’t know why this happens.
Graves’ disease is the most common cause of hyperthyroidism. The condition accounts for at least 90 per cent of all patients with hyperthyroidism. It is an autoimmune condition. The immune system normally produces antibodies to protect us and are designed to target a specific virus, bacteria or other foreign substance. Here, it is attacking our own system. An enemy within us!
Clinically, hyperthyroidism presents with palpitations, nervousness, tremor, heat intolerance, weight loss, muscular weakness and quite often there is goiter.
In Graves’ eye disease, the eyes are painful, red and watery – particularly in sunshine or wind. The eye lids and tissues around the eyes are swollen with fluid. The eyeballs bulge out of their sockets (exophthalmos). Because of eye muscle swelling, the eyes are unable to move normally and there may be blurred or double vision. Some patients have decreased colour vision as well.
With treatment, in most patients, the eyes tend to get somewhat better when the thyroid abnormality has been treated.
Hashimoto’s disease – underactive thyroid
There is another autoimmune thyroid condition called Hashimoto’s thyroiditis. It is named after Japanese physician Hakaru Hashimoto (1881−1934), who first described the symptoms in 1912. It affects more women than men.
This condition is characterized by the destruction of thyroid cells by various cell- and antibody-mediated immune processes. This condition is the most common cause of hypothyroidism. The treatment of choice for Hashimoto thyroiditis is thyroid hormone replacement.
Hypothyroidism causes many symptoms: weight gain, lethargy, cold intolerance, menstrual irregularities, depression, constipation, and dry skin. Deficiency of thyroid hormones in children leads to dwarfism and mental retardation.
Treatment of hypothyroidism with synthetic thyroid hormone is usually simple, safe and effective. Finding an adequate replacement dosage of thyroid may take a little time.
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