Which sign would suggest a TSH-secreting pituitary adenoma as the cause of hyperthyroidism?

Which sign would suggest a TSH-secreting pituitary adenoma as the cause of hyperthyroidism?

• A. Exophthalmos
• B. Bitemporal hemianopsia
• C. Diffuse goiter with nodularity
• D. Palpable thyroid bruit

Answer: (B)

Pituitary mass effect causing a visual field defect indicates a pituitary source of hyperthyroidism. A TSH-secreting pituitary adenoma enlarges and can press on the optic chiasm, producing bitemporal hemianopsia. This sign points to the thyroid hormones being driven by pituitary TSH rather than by a primary thyroid problem. Other signs fit thyroid gland disease more than pituitary causes: exophthalmos is common in autoimmune hyperthyroidism like Graves; diffuse goiter with nodularity and a thyroid bruit reflect thyroid-level pathology with changes in vascularity. So the presence of bitemporal hemianopsia best signals a pituitary origin.

Pituitary mass effect causing a visual field defect indicates a pituitary source of hyperthyroidism. A TSH-secreting pituitary adenoma enlarges and can press on the optic chiasm, producing bitemporal hemianopsia. This sign points to the thyroid hormones being driven by pituitary TSH rather than by a primary thyroid problem. Other signs fit thyroid gland disease more than pituitary causes: exophthalmos is common in autoimmune hyperthyroidism like Graves; diffuse goiter with nodularity and a thyroid bruit reflect thyroid-level pathology with changes in vascularity. So the presence of bitemporal hemianopsia best signals a pituitary origin.