The thyroid gland is a butterfly-shaped gland in the neck, lying in front of the trachea and larynx. The gland produces two hormones called triiodothyronine (T3) and thyroxine (T4).
These hormones are responsible for our metabolism (i.e. how you break down food and use energy). In hyperthyroidism, the thyroid releases too much of the hormones.
Symptoms of Hyperthyroidism
An excess of the T3 and T4 hormones can cause:
• Difficulty concentrating
• Increased sweating
• Increased appetite
• Intolerance of warm temperatures
• Weight loss
• An enlarged thyroid gland
• Irregular menstrual periods (or no periods)
• Upset stomach
• High blood pressure
• Nausea and vomiting
• Irregular pulse or heartbeat
• In men, breast development
You don’t have to have all of these symptoms to have hyperthyroidism.
What Causes Hyperthyroidism?
The majority of cases of hyperthyroidism are caused by Graves’ disease, an auto-immune disease where the immune system produces antibodies to the thyroid, triggering it to go into overdrive.
Genetic and environmental factors are thought to be responsible for this immune deregulation. It can be hereditary, running in families.
Other factors, such as damage to the thyroid by radiation and certain drug therapies, including HIV treatments, can result in hyperthyroidism. Cigarette smokers also have a two-fold increased risk of the disease.
If you don’t have Graves’ disease, there are other causes, such as inflammation of the thyroid gland (caused by a virus), or inflammation caused by an immune response.
Sometimes women who have just given birth will develop an inflamed thyroid, commonly known as postpartum thyroiditis. Taking too much hormone medication can also trigger hyperthyroidism.
It is diagnosed by physical examinations and blood tests. The doctor will look for signs of an enlarged thyroid and take a blood pressure reading. He will also take blood to check for elevated levels of T3 and T4, as well as reduced levels of a thyroid-stimulating hormone.