Endocrine Weight Loss Thyroid Function and Weight Loss 2

Question 1

Which finding would be expected in a patient with primary hyperthyroidism causing unintentional weight loss?

Accepted Answer

Low TSH, elevated free T4

Answer

Primary hyperthyroidism (e.g., Graves' disease) is characterized by excess thyroid hormone production, which suppresses TSH via negative feedback, resulting in low TSH and high free T4.

Question 2

Graves' disease causes hyperthyroidism through which unique mechanism?

Accepted Answer

TSH receptor-stimulating antibodies (TRAb) that mimic TSH action

Answer

In Graves' disease, thyroid-stimulating immunoglobulins (a subtype of TRAb) bind and chronically activate TSH receptors, driving unregulated thyroid hormone synthesis and secretion.

Question 3

A euthyroid obese patient requests thyroid hormone supplementation to boost weight loss. The evidence-based response is:

Accepted Answer

Thyroid hormone supplementation is not indicated and risks thyrotoxicosis, bone loss, and arrhythmia

Answer

Thyroid hormone misuse for weight loss in euthyroid individuals is not evidence-based and carries significant risks including iatrogenic thyrotoxicosis, atrial fibrillation, and accelerated bone loss.

Question 4

Which condition can cause low TSH and low free T4, mimicking central hypothyroidism, in a hospitalized or critically ill patient?

Accepted Answer

Non-thyroidal illness syndrome (sick euthyroid syndrome)

Answer

Non-thyroidal illness syndrome occurs during acute illness; reduced T4-to-T3 conversion and suppressed hypothalamic TRH lead to low TSH and low thyroid hormone levels despite structurally normal thyroid glands.

Question 5

Which dietary mineral deficiency most directly impairs thyroid hormone synthesis?

Accepted Answer

Iodine

Answer

Iodine is an essential substrate for thyroid hormone synthesis; deficiency leads to goiter and hypothyroidism because T3 and T4 both require iodine atoms.

Endocrine Weight Loss Practice Test

Endocrine Weight Loss Practice Test

Endocrine Weight Loss Thyroid Function and Weight Loss 2