Individuals with hyperthyroidism usually tell their doctors about symptoms such as rapid heart rate, intense fatigue, inability to tolerate a hot environment, and constant nervousness, jitteriness, or irritability. In addition, doctors look for physical signs such as weight loss, rapid heartbeat, slight tremors of the hands, or excessive sweating. The presence of such symptoms and signs strongly suggests the need for diagnostic testing for hyperthyroidism.

Hyperthyroidism is diagnosed from blood tests:

Abnormally high levels of T3 and T4. This indicates that hyperthyroidism is present.
An unusually low level of circulating thyroid stimulating hormone (TSH). This is normally due to an abnormality within the thyroid gland.

In some cases of hyperthyroidism, a special diagnostic scan of the thyroid gland using radioactive iodine Iodine that contains a radioactive component. This element is chemically depicted as 131I. This form of iodine, which puts out intense energy, is used in a special test to diagnose thyroid disease. called radioactive iodine uptake (RAIU) testing may be particularly useful. This test is often done on an outpatient basis in the nuclear medicine department of a hospital.

RAIU testing shows whether:

The entire thyroid gland is overactive, in which case, a large amount of radioactive iodine is "taken up" by the thyroid.
Only portions of the thyroid are overactive. Significant amounts of radioactive iodine are "taken up" by portions of the thyroid, not the entire gland.

Nice To Know:

Typically, Graves' disease The most common form of hyperthyroidism or high levels of circulating thyroid hormone. Graves' disease is an autoimmune disorder of the thyroid gland that causes excessive production and release of thyroid hormone. Hyperthyroid eye and skin changes are sometimes associated with this condition. produces increased iodine A chemical element found in seawater and other sources. This chemical is necessary to produce thyroid hormone. Table salt labeled iodized contains added iodine and, for most people, is an important source of dietary iodine. uptake throughout the thyroid gland. Nodular thyroid disease A condition of the thyroid gland characterized by areas of overactivity within the thyroid gland. These areas are known as thyroid nodules. The exact cause of nodular thyroid disease, which may result in hyperthyroidism, is not known. produces a scan that shows patches of increased iodine uptake surrounded by areas with normal uptake.

How Is Graves' Disease Diagnosed?

Most people with hyperthyroidism, or about 95 percent, are eventually diagnosed with Graves' disease.

The diagnosis is confirmed through laboratory testing.

In people with Graves' disease, blood tests usually demonstrate:

Increased levels of T3
Increased levels of T4
Low levels of TSH
Presence of thyroid stimulating antibodies

A radioactive scan, such as RAIU testing, is usually not necessary to confirm the diagnosis of Graves' disease. If a scan is performed, it typically shows increased uptake of radioactive iodine throughout an enlarged thyroid gland. Areas of iodine uptake represent those areas in the gland producing thyroid hormone A chemical substance produced by the thyroid gland and released into the bloodstream. It interacts with almost all body cells, causing them to increase their metabolic activity. Two forms of thyroid hormone, abbreviated as T3 and T4, are found in bloodstream. .

How Is Nodular Thyroid Disease Diagnosed?

When a physical exam is performed, the thyroid is usually larger than normal; however, there is usually no pain associated with an enlarged thyroid. As untreated disease progresses, individual lumps or nodules may be felt with the fingertips.

RAIU testing may be used to diagnose nodular thyroid disease. In individuals with this form of hyperthyroidism, this test shows clusters or nodules of abnormal thyroid cells among areas of normal cells. After this test, doctors see "spots" of overactivity on radioactive iodine uptake scanning film.

Back to Top of Page

<Back Next>

To continue, select a heading below:
What Is Hyperthyroidism? What Causes It? Symptoms Of Hyperthyroidism How Is It Diagnosed? Is Hyperthyroidism Serious? Treatment Of Hyperthyroidism Who Needs Surgery?	Hyperthyroid Eye Disease Looking After Yourself Hyperthyroidism And Pregnancy Common Questions Putting It All Together Glossary Sources Of Information






	If you have a medical question, visit our Discussion Forum

	Home All Our Topics Contact Us Site Map Back to Top of Page

Thanks for visiting our award winning site.

We strive to make every page helpful to every reader.

Let us know if we've succeeded or how we can improve your experience on our site even more.

We read every email

comments@ehealthMD.com


	Copyright © 2002-2005 Health Information Publications. The information provided on this Web site has been developed exclusively by and for Health Information Publications and ehealthMD and may not be copied without written permission. The information provided is for general information only and is not intended to replace the advice of your health-care provider. This is original material developed by Health Information Publications, Copyright © 1990-2005

	Medical Illustrations Copyright ©Nucleus Medical Art 2004. All rights reserved.

	Last updated October 2004
	Page 4 of 14