1. What is the thyroid?
The thyroid is a butterfly-shaped gland that resides in the lower portion of the neck below the voice box or larynx. It releases two hormones called T3 and T4, which are responsible for controlling the body's metabolism. The thyroid does not just release a certain amount of T3 and T4 on its own, but is controlled by a small gland in the brain called the pituitary. The pituitary releases a hormone called TSH or thyroid stimulating hormone which in turn triggers the thyroid to release T3 and T4.
If the thyroid hormone level is high then the pituitary will decrease the amount of TSH that it releases. Conversely, if the thyroid hormone is low the pituitary will release more TSH causing the thyroid to release more T4 and T3.
2. What is hyperthyroidism and what causes it?
Hyperthyroidism is the overproduction of the thyroid hormone which is most often caused by Grave's disease. In Grave's disease the body produces antibodies to the thyroid, causing the thyroid to enlarge (goiter) and to overproduce thyroid hormone. Other causes of hyperthyroidism include thyroiditis and thyroid nodules.
3. What are the symptoms of hyperthyroidism?
Symptoms of hyperthyroidism include:
• Fast heart beat
• Anxiety
• Tremor or shaking
• Chest pain
• Weight loss
• Sweating
• Fatigue
• Insomnia
• Irregular menstrual cycles
4. How is hyperthyroidism diagnosed?
Hyperthyroidism is diagnosed with blood tests that measure the TSH and thyroid hormone levels. Hyperthyroidism is present when the TSH is low or undetectable and the thyroid hormone level is high. Hyperthyroidism can also be diagnosed with a thyroid uptake scan which will discern what type of hyperthyroidism is present, either Grave's disease, thyroiditis or toxic nodular goiter.
5. How is hyperthyroidism treated?
Treatment options include medications, radiation and surgery. Antithyroid medications include methimazole and propylthiouracil (PTU). These medications work by reducing the amount of thyroid hormone produced.
Another class of medications called beta-blockers are used temporarily to control hyperthyroid symptoms such as rapid heart beat, anxiety and tremor until these symptoms are resolved using the previously mentioned medicines, radiation or surgery.
Radioactive iodine is used to permanently ablate the thyroid tissue. This the most common form of treatment and the majority of patients will develop hypothyroidism after radiation. However, some patients will require a second dose for complete resolution. Individuals who have received radiation treatment will have to avoid contact with children and pregnant women for up to a week because of the risk of exposing them to the radiation.
The last treatment option is surgical removal of the thyroid. This is a permanent solution but has several risk factors due to the location of the thyroid in the neck. Sometimes surgery is the advised because of a large goiter, medication failure or a patient declines radioactive treatment.
After treatment a patient must have close follow-up with their health care provider to monitor the thyroid hormone levels in the blood.
