Graves' disease is the most common cause of thyrotoxicosis. The disease is named after the Irish physician who first described it in 1835. It affects approximately 1 in 100 of the adult population. Graves' disease can be seen at any age, but is more common in young to middle-aged women. Females are5 to 10times more likely to get Graves' disease than men. Graves disease occurs in 1.6/1000 pregnancies which is discussed in detail under the heading of Maternal Thyrotoxicosis.The risk to a monozygotic twin ofdeveloping like its sibling Grave's disease is 35%.What triggers genetically susceptical individuals to develop Grave's disease is not known. Factors suggested are infection,pregnancy and stress.
Graves' disease is an autoimmune disease (a disease where the patient's own immune system attacks the thyroid). The autoantibodies attach to the patient's thyroid gland and stimulate it to make thyroid hormones, and hence result in a state of thyrotoxicosis. Graves' disease is now defined as hyperthyroidismas a result of stimulation of the thyroid by thyrotrophin receptor stimulating antibodies (TRAb). The mechanism is that circulating IgG antibodies bind to and activate the G-protein-coupled thyroid stimulating hormone receptor.This results in an increase activity of the thyroid gland due an increase in the number and activity of the individual thyroid cells.The thyroid itself becomes enlarged.
One interesting problem is infertility which is cured by therapy. All too often we have seen patients in IVF programs who have had undiagnosed thyrotoxicosis and become fertile when made euthyroid (normal thyroid function).