Your thyroid is a small gland found at the base of your neck, just below your Adam's apple. The thyroid produces two main hormones called T3 and T4. These hormones travel in your blood to all parts of your body. The thyroid hormones control the rate of many activities in your body. These include how fast you burn calories and how fast your heart beats. All of these activities together are known as your body's metabolism. A thyroid that is working right will produce the right amounts of hormones needed to keep your body’s metabolism working at a rate that is not too fast or too slow.
Dr. Tom Connally is the Medical Director of the Norman Regional Health System Endocrine Surgery Program and a pioneer in the area of minimally-invasive thyroid and parathyroid surgeries. He is also an active member of the American Association of Endocrine Surgeons.
For more information about endocrine diseases and surgical options, please visit http://endocrinediseases.org/
Thyroid disorders can be hard to diagnose because their symptoms can be linked to many other health problems. Your doctor will start by taking a medical history and asking if any of your family members has a history of thyroid disorders. Your doctor will also give you a physical exam and check your neck for thyroid nodules. Depending on your symptoms, your doctor may also do other tests, such as:
Testing the level of thyroid stimulating hormone (TSH) in your blood can help your doctor figure out if your thyroid is overactive or underactive. TSH tells your thyroid to make thyroid hormones. Depending on the results, your doctor might order another blood test to check levels of one or both thyroid hormones in your blood. If your doctor suspects an immune system problem, your blood may also be tested for signs of this.
Radioactive iodine uptake test
For this test, you swallow a liquid or capsule containing a small dose of radioactive iodine (radioiodine). The radioiodine collects in your thyroid because your thyroid uses iodine to make thyroid hormones. Then, a probe placed over your thyroid measures the amount of radioiodine in your thyroid. A high uptake of radioiodine means that your thyroid is making too much of the thyroid hormones. A low uptake of radioiodine means that your thyroid is not making enough of the thyroid hormones.
A thyroid scan usually uses the same radioiodine dose that was given by mouth for your uptake test. You lie on a table while a special camera creates an image of your thyroid on a computer screen. This test may be helpful in showing whether a thyroid nodule is cancerous. Three types of nodules show up in this test:
Thyroid nodules that take up excess radioiodine are making too much of the thyroid hormones, causing hyperthyroidism. These nodules show up brightly on the scan and are called "hot" nodules.
Thyroid nodules that take up the same amount of radioiodine as normal thyroid cells are making a normal amount of thyroid hormones. These are called "warm" nodules. Thyroid nodules that do not take up radioiodine are not making thyroid hormones. They appear as defects or holes in the scan and are called "cold" nodules. Hot nodules are almost never cancerous. A small percentage of warm and cold nodules are cancerous.
Thyroid fine needle biopsy
This test is used to see if thyroid nodules have normal cells in them. Local anesthetic may be used to numb an area on your neck. Then, a very thin needle is inserted into the thyroid to withdraw some cells and fluid. The withdrawal of cells and fluid is called a biopsy. A special type of doctor called a pathologist examines the cells under a microscope to see if they are abnormal. Abnormal cells could mean thyroid cancer.
The thyroid ultrasound uses sound waves to create a computer image of the thyroid. This test can help your doctor tell what type of nodule you have and how large it is. Ultrasound may also be helpful in detecting thyroid cancer, although by itself it cannot be used to diagnose thyroid cancer. You may have repeat thyroid ultrasounds to see if your nodule is growing or shrinking.