Which statement about Graves' disease is correct?

• A. It is the most common form of hyperthyroidism
• B. It is the most common form of hypothyroidism
• C. It is caused by bacterial infection
• D. It presents primarily with hair loss

Answer: (A)

Graves' disease is an autoimmune condition in which antibodies stimulate the TSH receptor, causing the thyroid to produce excess thyroid hormone. This makes it the most common cause of hyperthyroidism in adults, which is why the statement is correct. The condition often presents with symptoms of hyperthyroidism such as weight loss, heat intolerance, rapid heart rate, and sometimes eye signs (exophthalmos) or a diffuse goiter. It is not a cause of hypothyroidism, so the claim about hypothyroidism is incorrect. It is not driven by a bacterial infection, as it stems from immune-mediated antibody stimulation. Hair loss can occur with thyroid disorders, but it is not the primary or defining feature of Graves' disease.