Which type of goiter (enlarged thyroid) can be reduced by the addition of iodine to the diet?
A) Hyperthyroid goiter, in which thyroxine does not turn off the pituitary's secretion of TSH
B) Hyperthyroid goiter, in which the thyroid is activated by high levels of thyroxine
C) Hypothyroid goiter, involving low functional thyroxine levels and high thyrotropin levels
D) Hypothyroid goiter, involving high functional thyroxine levels and low thyrotropin levels
E) All types of goiter

Question

Quizplus · Accepted Answer

Hypothyroid goiter occurs due to low levels of functional thyroxine and high levels of thyrotropin. The addition of iodine to the diet can help reduce this type of goiter as iodine is required for the production of thyroxine. When the thyroid gland does not have sufficient iodine, it cannot produce enough thyroxine, resulting in goiter. However, iodine will not be helpful in reducing goiter caused by hyperthyroidism (either due to high levels of thyroxine or failure of thyroxine to turn off pituitary secretion of TSH), as the underlying cause is not a lack of iodine but rather an overproduction of thyroid hormone.

Which Type of Goiter (Enlarged Thyroid) Can Be Reduced by the Addition