Question

Normal:

free thyroxine T4: 0.8-1.8
TRH 5-25
TSH 0.3-5

Your cousin's value:
T4 0.4
TRH 25
TSH 10
Where is the malfunction is likely occurring?

hypothalamus

anterior pituitary

posterior pituitary

thyroid gland

Answer 1

The cousin's abnormal hormone levels indicate a malfunction most likely occurring in the thyroid gland, as indicated by low T4 and high TRH and TSH levels.

Step-by-step explanation:

The malfunction in thyroid hormone levels provided by the cousin's values indicates an issue most likely occurring at the thyroid gland. Free thyroxine (T4) levels are low at 0.4 (normal range: 0.8-1.8), while Thyrotropin-releasing hormone (TRH) and thyroid stimulating hormone (TSH) levels are elevated at 25 (normal range: 5-25) and 10 (normal range: 0.3-5) respectively. This suggests that the thyroid gland is not producing sufficient amounts of T4, despite the high levels of TSH which should stimulate the thyroid to produce more T4. As a result, the hypothalamus and pituitary gland are compensating for the low thyroid hormone levels by increasing TRH and TSH secretion. This feedback loop is part of normal thyroid regulation to maintain homeostasis.