Thyroid Question And Answers

Thyroid

 

Question 1. Describe The Indication Of Radioactive Iodine.
Answer:

The indications of radioactive iodine are:

• They are most commonly used as sodium salts of I31 and taken orally in hyperthyroidism.
• It emits β particles which destroy thyroid cells, so they are used in carcinoma of the thyroid.
• It is used for diagnostic purposes.

Question 2. Write Short Note On Radioactive I¹³¹.
Answer:

Radioactive Iodine ( I¹³¹ ) is an anti-thyroid drug, i.e. it destroys the thyroid tissue.

Read And Learn More: Pharmacology Question And Answers

Radioactive Iodine Pharmacokinetics

• Radioactive I¹³¹ is administered as the sodium salt of I¹³¹. It should be orally administered after dissolving in the water.
• Its physical half-life is of 8 days.

Radioactive Iodine  Mechanism Of Action

It is actively taken up by the thyroid gland, incorporate in colloids,s and emits X-rays and β-particles from within the follicles. The thyroid follicular cells are affected from within and undergo pyknosis and necrosis followed by fibrosis without damaging neighboring tissues. This can destroy the gland from within and has a selective thyroid-destroying effect.

Radioactive Iodine  Diagnostic

About 25 to 100μ curie is given; counting or scanning is done at intervals.

Radioactive Iodine  Indications

• Hyperthyroidism due to Graves disease/toxic nodular goiter.
• In metastatic carcinoma of the thyroid I¹³¹ can be used as palliative therapy after thyroidectomy.

Radioactive Iodine  Advantages

• Treatment with I¹³¹ is simple, conveniently given on an outpatient basis, and inexpensive.
• No surgical risk, scar, or injury to parathyroid glands/ recurrent laryngeal nerves.
• Once hyperthyroidism is controlled, a cure is permanent.

Radioactive Iodine  Adverse Effects

• Hypothyroidism: About 5-10% of patients of Graves disease treated with I131 become permanently hypothyroid every year. This probably reflects the natural history of Graves’ disease, because only a few patients with toxic nodular goiter treated with I¹³¹ develop hypothyroidism.
• Long latent period of response.
• Avoided during pregnancy
• Not suitable for young patients: they are more likely to develop hypothyroidism later and would then require lifelong T4 treatment.