The thyroid gland is an important endocrine gland of the human body. It is one of the largest glands in the body, lying just below the Adam’s apple. The thyroid produces two important hormones, thyroxine and triiodothyronine, which are important in controlling the rate of metabolism. Production of the two hormones is controlled by another hormone: thyroid stimulating hormone (TSH) produced by the pituitary gland.
Causes of Graves' Disease
The TSH released by the pituitary activates the thyroid by binding to specific receptors on thyroid cells. These are called TSH receptors. In the case of a person suffering from Graves' disease, the immune system produces autoantibodies against TSH receptors. These autoantibodies bind to the TSH receptors thereby stimulating the cells to produce thyroxine and triiodothyronine. In short, the autoantibodies mimic the action of TSH.
Graves' disease was first described by Sir Robert Graves in 1835 and is the most common cause of hyperthyroidism, a condition in which the thyroid becomes enlarged and overactive. Females are more likely to suffer from this condition than males and heredity seems to play a significant role in its development. This condition generally presents itself during early adolescence.
Signs and Symptoms of Graves' Disease
The most prominent sign of Graves' disease is goiter or enlargement of the thyroid. Graves' ophthalmopathy, or thyroid eye disease, causes protrusion of eyes. Swelling, redness and conjunctivitis are also seen. Pretibial myxedema is a rare complication in patients with Graves' disease. In this condition, the skin of the lower legs becomes lumpy and reddish.
Apart from the above-mentioned conditions, which occur due to the autoimmunity, all other signs and symptoms associated with Graves' disease, like hypertension, hyperreflexia, tremor, weight loss, increased appetite, muscle weakness, muscle degeneration, chronic sinus infection and insomnia, are due to hyperthyroidism. Hyperthyroidism can also lead to reduced bone density, osteoporosis and increased rate of bone fracture.
Treatment of Graves' Disease
The autoimmune processes that cause Graves' disease are as yet not well understood and thus treatment procedures target the thyroid and try to reduce the overproduction of thyroid hormones. Three different methods are generally used in the treatment of this condition – the antithyroid drugs carbimazole, methimazole and propylthiouracil (which reduce production of thyroid hormones), ingestion of radioactive iodine (leads to partial or complete destruction of the thyroid) and removal of thyroid gland by surgery. Apart from these major therapies, symptomatic treatment is also given. The prognosis is good if the condition is diagnosed and treated started early.
References
Webmd.com “Understanding Grave’s Disease – The Basics” (Accessed 27th May 2010)
Medterms.com “Definition of Grave’s Disease” (Accessed 27th May 2010)
Jitendra Rathod - Jitendra holds a Master's Degree in Microbiology. He had been a Lecturer, teaching the subject to undergrads and postgrads for 8 years.
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