The occurrence of hyperthyroidism following administration of supplemental iodine to subject with endemic iodine deficiency goitre is known as
**Core Concept**
The question is testing the understanding of the Wolff-Chaikoff effect, a phenomenon where excessive iodine intake can lead to a temporary inhibition of thyroid hormone synthesis in individuals with iodine deficiency. This concept is crucial in the management of patients with endemic goitre or those with a history of thyroid surgery.
**Why the Correct Answer is Right**
The Wolff-Chaikoff effect occurs when the thyroid gland is exposed to high levels of iodine, which can lead to the formation of iodine-containing complexes that inhibit the enzyme thyroid peroxidase (TPO). TPO is essential for the synthesis of thyroid hormones, and its inhibition results in a decrease in thyroid hormone production. This effect is reversible and does not affect the thyroid gland's ability to respond to thyroid-stimulating hormone (TSH). The Wolff-Chaikoff effect is a protective mechanism that prevents the thyroid gland from being over-stimulated by excessive iodine intake.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the Wolff-Chaikoff effect. The correct term is not related to the administration of iodine in patients with endemic goitre.
**Option B:** This option is incorrect because it is a different condition altogether, characterized by the presence of a goitre in the absence of iodine deficiency.
**Option C:** This option is incorrect because it is a different condition characterized by the presence of a goitre due to excessive iodine intake, not the temporary inhibition of thyroid hormone synthesis.
**Clinical Pearl / High-Yield Fact**
The Wolff-Chaikoff effect is a critical consideration in patients with endemic goitre or those with a history of thyroid surgery, as it can lead to a temporary worsening of hyperthyroidism following iodine supplementation. It is essential to monitor thyroid function tests closely in these patients to avoid any adverse effects.
**Correct Answer: Jod-Basedow Phenomenon.**