Hyperthyroidism is the medical term for an overactive thyroid (hyper = excessive). In people with hyperthyroidism, the thyroid gland produces too much thyroid hormone. When this occurs, the body's metabolism is increased, which can cause a variety of symptoms.
WHAT IS THE THYROID? The thyroid is a butterfly-shaped gland in the middle of the neck, located below the larynx (voice box) and above the clavicles (collarbones). The thyroid produces two hormones, triiodothyronine (T3) and thyroxine (T4), that regulate how the body uses and stores energy (also known as the body's metabolism).
The thyroid is controlled by a gland in the brain, known as the pituitary. The pituitary produces thyroid-stimulating hormone (TSH), which stimulates the thyroid to produce T3 and T4.
Graves' disease — Graves' disease is the most common cause of hyperthyroidism. It is not clear why Graves' disease develops in most people, although it more common in certain families.
In people with Graves' disease, the immune system produces an antibody that stimulates the thyroid gland to produce too much thyroid hormone. This is most common in women between the ages of 20 and 40 years, but can occur at any age in men or women. The thyroid gland enlarges (called a goiter) and makes excessive amounts of thyroid hormone, causing symptoms of hyperthyroidism.
Some people develop eye problems (called Graves' ophthalmopathy or orbitopathy), which causes dry, irritated or red eyes, and in severe cases may cause double vision. Others develop swelling behind or around the eyes that causes the eyes to bulge out, or inflammation of muscle in the eyelids that can cause excessive lid opening. The more severe manifestations of Graves’ eye disease are uncommon, except in smokers. In its most severe form, people with Graves' ophthalmopathy can develop inflammation of the optic nerves, which can result in loss of vision.
One or more thyroid nodules (small growths or lumps in the thyroid gland) can produce too much thyroid hormone. The nodule is then called a hot nodule, toxic nodule, or when there is more than one, a toxic nodular goiter.
Painless ("silent or lymphocytic") thyroiditis and postpartum thyroiditis are disorders in which the thyroid becomes temporarily inflamed and releases thyroid hormone into the bloodstream, causing hyperthyroidism. Postpartum thyroiditis can occur several months after delivery. The hyperthyroid symptoms may last for several months, often followed by several months of hypothyroid symptoms, such as fatigue, muscle cramps, bloating, and weight gain.
Subacute (granulomatous) thyroiditis is thought to be caused by a virus. It causes a painful, tender, enlarged thyroid gland. The thyroid becomes inflamed and releases thyroid hormone into the blood stream; the hyperthyroidism resolves when the viral infection improves, and may also be followed by several months of hypothyroid symptoms.
Taking too much thyroid hormone medication for hypothyroidism
Women who take antithyroid drugs and want to become pregnant should discuss this with their doctor or nurse. There are risks to the mother and developing baby if hyperthyroidism is not well controlled; these risks can be avoided or minimized with frequent monitoring and medication adjustment throughout the pregnancy.
Women who are pregnant or breastfeeding should not be treated with radioactive iodine. Having radioactive iodine treatment before becoming pregnant usually eliminates the need for antithyroid drugs and any possible associated risks. A woman should wait at least six months after radioactive iodine treatment before trying to become pregnant.
Genetic risk factors for COPD include severe deficiency of alpha-1 antitrypsin, a protein that protects the lungs.
Anxiety, irritability, trouble sleeping.
Weakness (in particular of the upper arms and thighs, making it difficult to lift heavy items or climb stairs or get up from a chair).
Tremors (of the hands).
Perspiring more than normal, difficulty tolerating hot weather
Rapid, forceful, or irregular heartbeats
Weight loss in spite of a normal or increased appetite.
Frequent bowel movements
Hyperthyroidism can be diagnosed with blood tests that measure the amount of thyroid hormone and thyroid-stimulating hormone (TSH). Typically, the thyroid hormone level is high and the TSH level is low. A thyroid scan may also be recommended to help determine the cause of hyperthyroidism (Graves' disease, toxic nodular goiter or thyroiditis).
Hyperthyroidism can be treated using medicine, radioiodine or surgery. Many factors, such as your age and the severity and type of hyperthyroidism, as well as your preferences, are important in determining which treatment is best.
Antithyroid drugs : Antithyroid drugs work by decreasing how much thyroid hormone the body makes.While taking antithyroid drugs, you will have a blood test for thyroid hormone every four to six weeks until your hyperthyroidism is under control.
Beta-blockers : They can control many of the bothersome symptoms, such as rapid heart rate, tremors, anxiety, and heat intolerance. Once the hyperthyroidism is under control (with antithyroid drugs, surgery, or radioactive iodine), the beta-blocker is stopped.
Radioactive Iodine : Destroying the thyroid with radioiodine, called ablation, is a permanent way to treat hyperthyroidism. The amount of radiation used is small and does not cause cancer, infertility, or birth defects. Radioiodine is given in liquid or capsule form, and it works by destroying much of the thyroid tissue. This takes about 6 to 18 weeks.
Sugery is recommended when:
A large goiter blocks the airways, making it difficult to breathe
You cannot tolerate antithyroid drugs and you do not want to use radioiodine
There is a nodule in the thyroid gland that could be cancer
The follow-up after surgery includes regular appointments to test your thyroid hormone levels and monitor for signs of hypo- and hyperthyroidism. Most people develop hypothyroidism after surgery and require treatment with thyroid hormone.