Hyperthyroidism is the disease caused by increase in secretion of thyroid hormones.
Before knowing about hyperthyroidism lets see, what is thyroid gland which causes hyperthyroidism.
Thyroid is an endocrine gland situated at the roof of neck on either side of trachea. Its weight is about 20-30 gm in adults. Thyroid is larger in females compared to males.
the structure and function of thyroid gland changes in different stages of sexual cycle in female. its function increased slightly during pregnancy and lactation and decrease during menopause.
Hormones of thyroid gland
There are three types of hormones secreted by thyroid gland.
- T4 (Thyroxine)
T4 is also called Thyroxine and it is major hormone among three, its secretion is about 90%..
Causes of hyperthyroidism
Increased secretion of thyroid hormone is caused mainly by Graves disease and thyroid adenoma.
Graves disease is an autoimmune disease and it is the most common cause of hyperthyroidism.
Normally, Thyroid stimulating hormone (TSH) combines with receptors of thyroid cells and cause the synthesis and secretion of thyroid hormone.
In Graves disease, The B lymphocytes also called plasma cells produce autoimmune antibodies called Thyroid stimulating antibodies.
Those antibodies act like Thyroid stimulating hormone and combine with receptors of thyroid cell and cause synthesis and secretion of thyroid hormone.
Sometimes, a localised tumor develops in the thyroid tissue. It is known as Thyroid adema and it secret a large quantitie of thyroid hormone.
As far as Thyroid adenoma remains active, other parts of thyroid gland cannot secrete hormone because the hormone secreted from adenoma depress the production of thyroid stimulating hormone.
Symptoms and signs of hyperthyroidism
There are several signs and symptoms of hyperthyroidism in body.
1. Toxic goiter
Goiter means enlargement of the thyroid gland. it occurs both in hyperthyroidism and in hypothyroidism.
Goiter in hyperthyroidism is called Toxic goiter. Toxic goiter is the enlargement of thyroid gland with increased secretion of thyroid hormones caused by thyroid tumor.
2. Oligomenorrhea or amenorrhea
Amenorrhea refers to absence of maturation cycle and Oligomenorrhea means decreased frequency of menstrual bleeding.
Protursion of eyeball is called exophthalmos. most of the hyperthyroidism patients develop some degree of Protursion of eyeball but not all hyperthyroidism patients develop it.
4. Increased heat and sweating
Intolerance to heat as the body already produces lot of heat due to increased basal metabolic rate caused by excess of thyroxine.
It also increased sweating due to vasodilation.
5. Increased stimulation of neurones
Nervousness, extreme fatigue, inability to sleep, mild tremor in hands and psychoneurotic symptoms such as hyperexcitability, extreme anxiety or worry. All those symptoms are due to the excess stimulation of neurones in the central nervous system.
Other symptoms of hyperthyroidism are-
- Decreased body weight due to fat mobilization.
- Diarrhoea due to increased mobility of GI tract.
- Muscles weakness because of excess protein catabolism.
- cardiac failure.
Treatment of Hyperthyroidism
1. By using Antithyroid substance
Antithyroid substance are the drugs which suppress the secretion of thyroid hormones. Hyperthyroidism in early stage can be treated by antithyroid substance.
Three well known antithyroid substance are –
- High concentration of inorganic iodine.
2. By surgical removal
In advance case of Hyperthyroidism, treatment by using antithyroid substance is not possible. So, Thyroid gland of those patients must be removed.
Surgical removal of thyroid gland is called thyroidectomy. Before surgery, the patient is prepared by reducing the basal metabolic rate.
The high concentration of iodides is given for two weeks. it decreases the size of gland and blood supply to a very great extent.
Because of those precautions, the mortality after the operation decrease very much.
Eating well balanced diet may prevent Hyperthyroidism. stop eating junk food in excess. If you have any symptoms then please visit your doctor for Check up.