In Graves disease, a circulating autoantibody against the thyrotropin receptor provides continuous stimulation of the thyroid gland. This stimulatory immunoglobulin has been called long-acting thyroid stimulator (LATS), thyroid-stimulating immunoglobulin (TSI), thyroid-stimulating antibody (TSab), and TSH-receptor antibody (TRab).
Autoantibody titers in hyperthyroidism are as follows:
Graves disease - Significantly elevated anti-TPO, elevated TSab
Toxic multinodular goiter - Low or absent anti-TPO and TSab
Toxic adenoma - Low or absent anti-TPO and TSab
Patients without active thyroid disease may have mildly positive anti-TPO and TSab
Thyroid hormone excess causes left ventricular thickening, which is associated with an increased risk of heart failure and cardiac-related death. Thyrotoxicosis has been associated with dilated cardiomyopathy, [36] right heart failure with pulmonary hypertension, and diastolic dysfunction and atrial fibrillation. [15]
An increase in the rate of bone resorption occurs. Bone loss, measured by bone mineral densitometry, can be seen in severe hyperthyroidism at all ages and in both sexes. In mild subclinical disease, however, bone loss has been convincingly shown only in postmenopausal women.
(Fonte: Medscape.com)