Your thyroid is a small gland found at the base of your neck, just below your Adam's apple. It produces two main hormones called T3 and T4. These hormones travel in your blood to all parts of your body. The 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. One 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 the disorders. Your doctor will also give you a physical exam and check your neck for 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 it is overactive or underactive. TSH tells your thyroid to make the hormones. Depending on the results, your doctor might order another blood test to check levels of one or both T3 and T4 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 the gland because it uses iodine to make the hormones. Then, a probe placed over the gland measures the amount of radioiodine that is present. A high uptake of radioiodine means that your gland is making too much of the hormones. A low uptake of radioiodine means that your thyroid is not making enough of the T3 and T4 hormones.
The 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 on a computer screen. This test may be helpful in showing whether a nodule is cancerous. Three types of nodules show up in this test:
The nodules that take up excess radioiodine are making too much of the T3 and T4 hormones, causing hyperthyroidism. These nodules show up brightly on the scan and are called "hot" nodules.
The nodules that take up the same amount of radioiodine as normal cells are making a normal amount of T3 and T4 hormones. These are called "warm" nodules. The nodules that do not take up radioiodine are not making 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.
Fine needle biopsy
This test is used to see if the 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 gland 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.
This 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 cancer, although by itself it cannot be used to diagnose cancer. You may have to repeat the ultrasounds to see if your nodule is growing or shrinking.