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Graves’ disease is an autoimmune disease in which our immune system attacks our own thyroid tissue in such a way that the production of thyroid hormones is increased way, more than the body actually needs. Our immune system starts producing an antibody called “Thyroid Stimulating Immunoglobin” or TSI. This antibody attaches to the specific thyroid receptors and stimulates the overproduction of thyroid hormones.
Thyroid hormones (T3 and T4) normally affect almost all our normal body functions including our metabolism, breathing, heart rate, body temperature, muscle strength, sweat glands, menstrual cycle, body weight and cholesterol levels. If a person has hyperthyroidism, all these body functions speed up.
Signs And Symptoms Of Graves’ Disease
The clinical manifestations of this disease are related to the increased functions of thyroid hormones. The signs and symptoms of this disease are:
- Restlessness, fatigue
- Tremor of hands or fingers
- Anxiety and irritability
- Increased BMR, heat intolerance
- Warm, moist skin and increased perspiration, especially sweaty palms
- Unexplained sudden weight loss
- Diffuse enlargement of the thyroid gland (Swelling in the neck that moves when you swallow)
- Menstrual irregularities in women
- Decreased libido or erectile dysfunction
- Increased bowel motility, increased bowel frequency
- Rapid or irregular heartbeat (palpitations)
- Thick, red skin usually on the shins (pretibial myxedema) also called Graves' dermopathy.
- Bulging eyes (Graves' ophthalmopathy)
Many patients with Graves’ disease experience a condition called Graves’ ophthalmopathy, in which the eyeballs bulge out and the eyelids are retracted. This happens because antibodies attack the muscles and other tissues behind the eyeballs and cause inflammation, which leads to the peculiar symptom of bulging eyeballs (also called exophthalmos). This may also be associated with double vision, dry eyes and light sensitivity. This feature, when present, is the hallmark of Graves’ disease.
How Is Graves’ Disease Diagnosed?
A detailed medical history and physical examination usually guide your doctor to the diagnosis. Diffuse swelling of the thyroid, ophthalmopathy, dermopathy and signs of hyperthyroidism learly point towards Graves’ disease. Other factors like age, gender and heredity also help in the diagnosis because Graves’ disease is much more common in middle aged women.
The physician will then order any of the following laboratory tests to confirm the diagnosis:
- TSH levels: Ultrasensitive TSH test is the best screening test for thyroid diseases. TSH levels are decreased in hyperthyroidism.
- Free T3 and T4 levels: Triiodothyronine (T3) and Thyroxine (T4) are actually the names of thyroid hormones. Both these hormones are understandably elevated in Graves’ disease.
These three tests confirm hyperthyroidism, but they are not specific for Graves’ disease. The following tests are done to confirm a diagnosis of Graves’ disease:
- Radioactive Iodine Uptake Study: The thyroid gland uses iodine to make thyroid hormones. In this test, radioactive iodine is injected into the blood. This is then picked up by the thyroid gland. The thyroid gland is imaged with a Thyroid Scan. This scan detects the amount and distribution of iodine picked up from the blood by the thyroid gland. In Graves’ disease, iodine uptake is diffusely increased because of an overproduction of thyroid hormones.
- TSI assays: Detecting Thyroid Stimulating antibodies (TSIs) in the blood is diagnostic for Graves’ disease. It is a very specific test, as these antibodies are only positive in a patient with Graves’ disease.