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Diagnosis of Graves' Disease and Hyperthyroidism

The Clinical Exam, Blood Tests and Imaging Tests

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Updated: June 17, 2008

Diagnosing hyperthyroidism requires a complete clinical evaluation by a knowledgeable physician. During this clinical exam, the doctor typically should do the following:
  • Feel (also known as "palpating") your neck, looking for thyroid enlargement, nodules and masses. The most common sign of Graves is goiter/thyroid enlargement, which occurs in 90 percent of younger patients and 80 percent of older patients.
  • Palpate for what's known as "thrill," a detectable increased blood flow in the thyroid
  • Listen for "bruit" during palpation -- bruit is the sound of increased blood flow in the thyroid
  • Test your reflexes -- hyperresponsive reflexes can be a sign of hyperthyroidism
  • Check your heart rate, rhythm and blood pressure -- palpitations, atrial fibrillation, racing heartbeat, or high blood pressure can be signs of hyperthyroidism
  • Measure your weight -- weight loss can be a sign of hyperthyroidism
  • Measure body temperature -- fever can be a hyperthyroid sign
  • Examine your face and neck area -- some possible hyperthyroid signs include flushing or ruddiness of face/throat, blister-like bumps of the forehead and face (known as milaria bumps), spider veins in face and neck area
  • Examine your skin for some possible signs of hyperthyroidism, including vitiligo (loss of skin pigmentation), unusually smooth and young-looking skin, hives, increased acne
  • Observe the general quantity and quality of your hair -- thinning, fine or shedding hair can signal a thyroid condition
  • Observe any tremors, shakiness in the hands, or hyperkinetic movements -- i.e., table drumming, tapping feet, jerky movements (often more severe in children)
  • Examine your nails and hands for thyroid signs, including swollen fingertips (acropachy), moist hands and palms, and onycholysis (a separation of fingernail from underlying nail bed, also called Plummer's nails)
  • Evaluate your legs -- looking for lesions on the shins, known as pretibial myxedema or dermopathy
  • Examine your eyes -- red, bulging, dry, swollen, puffy, and watery eyes can be a sign of a thyroid problem. "Lid lag" -- when the upper eyelid doesn't smoothly follow downward movements of the eyes when you look down -- can also be a sign of thyroid issues.
An examination should also include a medical history, with particular attention to your personal and family history of any past or present thyroid, endocrine and autoimmune conditions.

In addition to the clinical examination, various tests are usually conducted. Hyperthyroidism can usually be confirmed by use of the TSH, T4 (or Free T4), T3 (or Free T3) and Radioactive Iodine Uptake (RAI-U) tests. In hyperthyroidism, test results would be as follows:

  • TSH Test -- usually low to undetectable. (Note: The low end of the TSH range is controversial. The new, recommended low is 0.3, but many doctors and most labs are still using the older, outdated bottom range number of 0.5.)
  • T4/Free T4 Test -- Normal to High
  • T3/Free T3 Test -- Normal to High
  • Radioactive Iodine Uptake (RAI-U) -- elevated.
In a radioactive iodine uptake (RAI-U) test, a small dose of radioactive iodine 123 is administered as a pill. Several hours later, the amount of iodine in your system is measured, accompanied by an x-ray. An overactive thyroid will typically have elevated RAI-U results -- the overactive gland usually takes up higher amounts of iodine than normal, and that uptake is visible in the x-ray. A thyroid that takes up iodine is considered "hot" -- or overactive, versus a cold or underactive thyroid. In Graves', RAI-U is elevated and you can see that the entire gland becomes hot. If you have thyroid nodules, RAI-U can show them and whether they are hot. If you are hyperthyroid due to a hot nodule, and not Graves' disease, the nodule will show up as hot, and the rest of your thyroid will be cold. Hot nodules may overproduce thyroid hormone but they are rarely cancerous. In someone with hyperthyroidism, the RAI-U would typically be normal only if hyperthyroidism is due to a pituitary tumor, or taking too much thyroid medication.

Graves' disease can be diagnosed using Thyroid Receptor Antibodies (TRAb) / Thyroid-Stimulating Immunoglobulins (TSI). The presence of TRAb/TSI test can confirm Graves' disease, and while experts can't agree, it's thought that from 75 to 95 percent of all Graves' patients will test positive for these antibodies. Practitioners do agree, however, that the presence of TRAb/TSI is considered diagnostic for Graves' disease. (Note: some patients with Graves' disease do not test positive for these antibodies.)

You can read more about the various blood tests used diagnose and manage thyroid problems in this article: Thyroid Blood Tests. Also, you can read more about the RAI-U in Thyroid Imaging Tests.

Sources:

AACE Thyroid Task Force, "American Association of Clinical Endocrinologists Medical Guidelines for Clinical Practice for the Evaluation and Treatment of Hyperthyroidism and Hypothyroidism," Endocrine Practice, Vol 8 No. 6, November/December 2002

Braverman, MD, Lewis E., and Robert D. Utiger, MD. Werner and Ingbar's The Thyroid: A Fundamental and Clinical Text. 9th ed., Philadelphia: Lippincott Williams & Wilkins (LWW), 2005.

De Groot, Leslie, M.D., Thyroid Disease Manager, Online book. Online

Moore, Elaine A. with Lisa Moore. Graves' Disease A Practical Guide. McFarland & Company, Inc., North Carolina, 2001

Shomon, Mary J., Living Well With Graves' Disease and Hyperthyroidism: What Your Doctor Doesn't Tell You...That You Need to Know , HarperCollins, New York 2005, Online

Weetman, Anthony P. "Graves' Disease" New England Journal of Medicine , Volume 343:1236-1248 October 26, 2000 Number 17

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