Which statement best describes Graves disease?

• A. Hyperthyroidism associated with thyroid-stimulating antibodies
• B. Hypothyroidism associated with anti-TPO antibodies
• C. Hyperparathyroidism with elevated PTH
• D. Euthyroid with no antibody involvement

Answer: (A)

Graves disease is an autoimmune form of hyperthyroidism caused by antibodies that stimulate the TSH receptor on thyroid cells. These thyroid-stimulating immunoglobulins mimic TSH, driving increased production and release of thyroid hormones (T3 and T4), which leads to a hypermetabolic state and suppression of TSH by negative feedback. Clinically, this often presents with diffuse thyroid enlargement and eye involvement due to immune-mediated inflammation.

This is why the statement describing hyperthyroidism associated with thyroid-stimulating antibodies is the best fit. The other options describe different conditions: antibodies against thyroid peroxidase are common in Hashimoto thyroiditis causing hypothyroidism; elevated PTH with hyperparathyroidism involves the parathyroid glands, not Graves; and being euthyroid with no antibody involvement describes a normal thyroid state, not Graves disease.