American Board of Pathology (ABPath) Practice Test

Graves Disease is the most common cause of hyperthyroidism. This autoimmune disorder leads to the overproduction of thyroid hormones due to an abnormal stimulation of the thyroid gland by antibodies that mimic thyroid-stimulating hormone (TSH). The result is increased levels of T3 and T4 hormones circulating in the body, which is characteristic of hyperthyroidism.

The pathophysiology involves the production of thyroid-stimulating immunoglobulins that cause the thyroid gland to enlarge and produce excessive hormones, leading to the clinical features associated with hyperthyroidism, such as weight loss, heat intolerance, and palpitations.

While other conditions like thyroiditis and toxic adenoma can cause hyperthyroidism, they are not as prevalent as Graves Disease. Thyroiditis may lead to temporary hyperthyroidism but often causes a subsequent hypothyroid phase and is less common as a primary cause compared to Graves Disease. A toxic adenoma can cause hyperthyroidism; however, it is typically less common in the general population and is usually a localized condition. Goiter, while it may be associated with various thyroid states, is not a specific cause of hyperthyroidism on its own.

Thus, recognizing Graves Disease as the predominant cause underscores its importance in