Question

Your cousin has gone to see her doctor due to increased fatigue, weight gain, and feeling cold. Her doctor thinks she may have an issue with thyroid hormone (T3,T4) production, as they regulate metabolism. The doctor begins treating your cousin with thyroxine (T4).

Which of the following best describes how thyroid stimulating hormone (TSH) levels will change over time with the thyroxine treatment?

TSH levels will be reduced after thyroxine treatment.

TSH levels will be increased after thyroxine treatment.

TSH levels will be unaffected by the thyroxine treatment.

Answer 1

In treating hypothyroidism with thyroxine (T4), the levels of TSH will typically decrease due to the negative feedback loop regulating thyroid hormone levels.

Step-by-step explanation:

Your cousin's doctor is correct in suspecting a thyroid hormone issue based on her symptoms of increased fatigue, weight gain, and feeling cold. These symptoms are indicative of hypothyroidism, a condition where the thyroid gland does not produce enough thyroid hormones (T3 and T4). These hormones are crucial for regulating the body's metabolism.

When treating hypothyroidism with thyroxine (T4), we expect to see changes in the levels of Thyroid Stimulating Hormone (TSH). TSH is released by the anterior pituitary gland and stimulates the thyroid to produce T3 and T4. The regulatory system operates on a negative feedback loop: high levels of T3 and T4 in the blood usually inhibit TSH release. By administering T4, the blood levels of thyroid hormones will increase, which should reduce the secretion of TSH from the pituitary gland.

So, the correct answer is that TSH levels will be reduced after thyroxine treatment. This therapy should help in normalizing your cousin's metabolic rate and alleviate the symptoms of hypothyroidism.