Thyroxine levels are raised in: March 2010

Ans. D: Grave's diseaseHypehyroidism is characterized by nervousness; weight loss; hyperphagia; heat intolerance; increased pulse pressure; a fine tremor of the outstretched fingers; a warm, soft skin; sweating; and a BMR from +10 to as high as +100. It has various causes. However, the most common cause is Graves' disease (Graves' hypehyroidism), which accounts for 60-80% of the cases. The condition, which for unknown reasons is much more common in women, is an autoimmune disease in which antibodies to the TSH receptor stimulate the receptor. This produces marked T4 and T3 secretion and enlargement of the thyroid gland (goiter). However, due to the feedback effects of T4 and T1,plasma TSH is low, not high. Another hallmark of Graves' disease is the occurrence of swelling of tissues in the orbits, producing protrusion of the eyeballs (exophthalmos). This occurs in 50% of patients and often precedes the development of obvious hypehyroidism.