cause of Grave's disease is still unknown as it is an autoimmune disease. However, there are several risk factors that are associated with Graves' disease:
- Hereditary
- Sex - susceptibility is increased in females. Hyperthyroidism due to Graves' disease has a female to male ratio of 7-8:1
- Age - typically, Graves' disease is a disease of young women, but it may occur in persons of any age. The typical age range is 20-40 years. Most affected women are aged 30-60 years.
- Stress
Causes of Hyperthyroidism
There are several causes of hyperthyroidism. Most often, the entire gland is overproducing thyroid hormone. This is called Graves' Disease. Less commonly, a single nodule is responsible for the excess hormone secretion ( 'hot' nodule).
Graves' disease
The most common underlying cause of hyperthyroidism is Graves' disease. In Graves' disease, patients' immune system mistakenly attack their thyroid gland, but instead of destroying the gland, an antibody called thyrotropin receptor antibody (TRAb) stimulates the thyroid to make excessive amounts of thyroid hormone.
'Hot' nodule
Hyperthyroidism can also be caused by a single nodule within the thyroid instead of the entire thyroid. Thyroid nodules usually represent benign (non-cancerous) lumps or tumors in the gland. These nodules sometimes produce excessive amounts of thyroid hormones. This condition is called "toxic nodular goiter". This single nodule is comprised of thyroid cells which have lost their regulatory mechanism which dictates how much hormone to produce. Without this regulatory control, the cells in this nodule produce thyroid hormone at a dramatically increased rate causing the symptoms of hyperthyroidism.
Inflammation of thyroid gland (thyroiditis)
thyroiditis can lead to the release of excess amounts of thyroid hormones that are normally stored in the gland. In subacute thyroiditis, the painful inflammation of the gland is believed to be caused by a virus, and the hyperthyroidism lasts a few weeks.
A more common painless form of thyroiditis occurs in one out of 20 women, a few months after delivering a baby and is, therefore, known as postpartum thyroiditis.
Thyroiditis generally last only a few weeks until the thyroid hormone stored in the gland has been exhausted.
Thyroid medication
Hyperthyroidism can also occur in patients who take excessive doses of any of the available forms of thyroid hormone. This is a particular problem in patients who take forms of thyroid medication that contains T3, which is normally produced in relatively small amounts by the human thyroid gland.
Risk factors of Hyperthyroidism
It is possible to develop hyperthyroidism with or without the risk factors listed below. However, the more risk factors you have, the greater your likelihood of developing hyperthyroidism.
There are two medical conditions that may increase your risk of hyperthyroidism:
Risk is greatest between the ages of 30 and 40 years. Hyperthyrodism rarely occurs before age 10.
Gender
Women are more likely than men to develop hyperthyroidism by a ratio of 7:1.
Genetic Factors
A family history of Graves’ disease or other forms of hyperthyroidism increases your risk.
Ethnic Background
People of Japanese ancestry appear to be at greater risk of hyperthyroidism. This may be attributed to a diet high in saltwater fish, which are rich sources of iodine.
Other
Supplementating iodine to a previously iodine-deficient diet may precipitate hyperthyroidism.
Complications of Graves' disease
Graves ophthalmopathy
Thyroid eye disease is an inflammatory condition which affects the orbital contents including the extraocular muscles and orbital fat. It is almost always associated with Graves' disease but may rarely be seen in Hashimoto's thyroiditis, primary hypothyroidism, or thyroid cancer. The ocular manifestations include soft tissue inflammation, eyelid retraction, proptosis, corneal exposure, and optic nerve compression.
Heart problems
Some of the most serious complications of hyperthyroidism involve the heart. These include a rapid heart rate, a heart rhythm disorder called atrial fibrillation and congestive heart failure. These complications are generally reversible with appropriate treatment.
Brittle Bones
Untreated hyperthyroidism can also lead to weak, brittle bones (osteoporosis). The strength of your bones depends, in part, on the amount of calcium and other minerals they contain. Too much thyroid hormone interferes with your body's ability to incorporate calcium into your bones.
Thyrotoxic crisis
Hyperthyroidism also places you at risk of thyrotoxic crisis — a sudden intensification of your signs and symptoms, leading to a fever, a rapid pulse and even delirium. This complication is rare, but if it occurs, seek immediate medical care.
Contributed by Lawrence Oh
References:
http://www.mayoclinic.com/health/graves-disease/DS00181/DSECTION=6
http://www.emedicine.com/med/byname/Graves-Disease.htm
http://healthgate.partners.org/browsing/browseContent.asp?fileName=19617.xml&title=Risk%20Factors%20for%20Hyperthyroidism
http://www.endocrineweb.com/pregnancy.html
http://en.wikipedia.org/wiki/Graves_disease
There are several causes of hyperthyroidism. Most often, the entire gland is overproducing thyroid hormone. This is called Graves' Disease. Less commonly, a single nodule is responsible for the excess hormone secretion ( 'hot' nodule).
Graves' disease
The most common underlying cause of hyperthyroidism is Graves' disease. In Graves' disease, patients' immune system mistakenly attack their thyroid gland, but instead of destroying the gland, an antibody called thyrotropin receptor antibody (TRAb) stimulates the thyroid to make excessive amounts of thyroid hormone.
'Hot' nodule
Hyperthyroidism can also be caused by a single nodule within the thyroid instead of the entire thyroid. Thyroid nodules usually represent benign (non-cancerous) lumps or tumors in the gland. These nodules sometimes produce excessive amounts of thyroid hormones. This condition is called "toxic nodular goiter". This single nodule is comprised of thyroid cells which have lost their regulatory mechanism which dictates how much hormone to produce. Without this regulatory control, the cells in this nodule produce thyroid hormone at a dramatically increased rate causing the symptoms of hyperthyroidism.
Inflammation of thyroid gland (thyroiditis)
thyroiditis can lead to the release of excess amounts of thyroid hormones that are normally stored in the gland. In subacute thyroiditis, the painful inflammation of the gland is believed to be caused by a virus, and the hyperthyroidism lasts a few weeks.
A more common painless form of thyroiditis occurs in one out of 20 women, a few months after delivering a baby and is, therefore, known as postpartum thyroiditis.
Thyroiditis generally last only a few weeks until the thyroid hormone stored in the gland has been exhausted.
Thyroid medication
Hyperthyroidism can also occur in patients who take excessive doses of any of the available forms of thyroid hormone. This is a particular problem in patients who take forms of thyroid medication that contains T3, which is normally produced in relatively small amounts by the human thyroid gland.
Risk factors of Hyperthyroidism
It is possible to develop hyperthyroidism with or without the risk factors listed below. However, the more risk factors you have, the greater your likelihood of developing hyperthyroidism.
There are two medical conditions that may increase your risk of hyperthyroidism:
- Certain viral infections
- Pregnancy—Five to eight percent of women develop postpartum thyroiditis (hyperthyroidism followed by hypothyroidism).
Risk is greatest between the ages of 30 and 40 years. Hyperthyrodism rarely occurs before age 10.
Gender
Women are more likely than men to develop hyperthyroidism by a ratio of 7:1.
Genetic Factors
A family history of Graves’ disease or other forms of hyperthyroidism increases your risk.
Ethnic Background
People of Japanese ancestry appear to be at greater risk of hyperthyroidism. This may be attributed to a diet high in saltwater fish, which are rich sources of iodine.
Other
Supplementating iodine to a previously iodine-deficient diet may precipitate hyperthyroidism.
Complications of Graves' disease
Graves ophthalmopathy
Thyroid eye disease is an inflammatory condition which affects the orbital contents including the extraocular muscles and orbital fat. It is almost always associated with Graves' disease but may rarely be seen in Hashimoto's thyroiditis, primary hypothyroidism, or thyroid cancer. The ocular manifestations include soft tissue inflammation, eyelid retraction, proptosis, corneal exposure, and optic nerve compression.
Heart problems
Some of the most serious complications of hyperthyroidism involve the heart. These include a rapid heart rate, a heart rhythm disorder called atrial fibrillation and congestive heart failure. These complications are generally reversible with appropriate treatment.
Brittle Bones
Untreated hyperthyroidism can also lead to weak, brittle bones (osteoporosis). The strength of your bones depends, in part, on the amount of calcium and other minerals they contain. Too much thyroid hormone interferes with your body's ability to incorporate calcium into your bones.
Thyrotoxic crisis
Hyperthyroidism also places you at risk of thyrotoxic crisis — a sudden intensification of your signs and symptoms, leading to a fever, a rapid pulse and even delirium. This complication is rare, but if it occurs, seek immediate medical care.
Contributed by Lawrence Oh
References:
http://www.mayoclinic.com/health/graves-disease/DS00181/DSECTION=6
http://www.emedicine.com/med/byname/Graves-Disease.htm
http://healthgate.partners.org/browsing/browseContent.asp?fileName=19617.xml&title=Risk%20Factors%20for%20Hyperthyroidism
http://www.endocrineweb.com/pregnancy.html
http://en.wikipedia.org/wiki/Graves_disease
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