59 Questions
Which hormone stimulates the release of thyroid-stimulating hormone (TSH) from the anterior pituitary?
Thyrotropin-releasing hormone (TRH)
What is the role of TSH in the thyroid gland?
Stimulates the thyroid to release thyroid hormones T3 and T4
How does the pituitary gland respond to high levels of thyroid hormones?
Secretes less TSH
What happens when thyroid hormone levels are low?
The pituitary secretes more TSH
How are normal levels of thyroid hormones maintained in a normal functioning hypothalamus-pituitary-thyroid axis?
By negative feedback
Which one of the following statements correctly describes the relationship between TSH and thyroid hormone levels?
When TSH levels are high, thyroid hormone levels are low.
Which term is used to describe the normal functioning of the thyroid gland with normal hormone levels?
Euthyroidism
What are the two broad categories into which thyroid disorders can be divided?
Functional disorders and enlargement of the thyroid gland
What is the term used to describe when there is an abnormal functional status of the thyroid hormone level in a person?
Hypothyroid
Which type of hypo or hyperthyroidism is due to diseases intrinsic to the thyroid?
Primary
Which of the following is a common cause of primary hypothyroidism in the western world?
Inflammation of the thyroid gland
What is the key component of thyroxine?
Iodine
Which of the following can lead to secondary hypothyroidism?
Disease or damage to the pituitary
Which of the following can lead to tertiary hypothyroidism?
Disease or damage to the hypothalamus
Which of the following can cause iatrogenic hypothyroidism?
Surgery to the thyroid gland
Which symptom is NOT associated with hypothyroidism?
Weight loss
Which sign is NOT commonly seen in hypothyroidism?
Excessive sweating
Which term describes an enlargement of the thyroid gland?
Goitre
Which type of hyperthyroidism is extremely rare and usually caused by tumors of the hypothalamus?
Tertiary hyperthyroidism
Which autoimmune disorder is responsible for primary hyperthyroidism?
Graves disease
What is the main cause of secondary hyperthyroidism?
TSH-secreting adenoma
Which drug can cause iatrogenic hyperthyroidism?
Amiodarone
Which type of goitre is characterized by the presence of nodules?
Nodular goitre
Which type of thyroid cancer is associated with characteristic histology findings of 'Orphan Annie eyes' and psammoma bodies?
Papillary carcinoma
Which type of thyroid cancer usually does not affect thyroid function and the patient remains euthyroid?
Papillary carcinoma
Which type of thyroid adenoma is characterized by the presence of eosinophilic cells?
Hürthle cell adenoma
What is the term used to describe the enlargement of the thyroid gland due to iodine deficiency?
Simple non toxic goiter
Which type of goiter is diffuse and toxic in nature?
Graves disease
What is the term used to describe a thyroid nodule that produces an excess amount of thyroid hormone?
Toxic adenoma
Which condition is characterized by the presence of autoimmune disease or infective causes leading to diffuse goiter?
Hashimoto's thyroiditis
Which blood test measures the response of the pituitary gland to circulating T4 and T3?
Serum TSH concentration
In primary hypothyroidism, what happens to the levels of TSH, T4, and T3?
↑TSH, ↓T4 and T3
What is the cause of secondary hypothyroidism?
Pituitary gland problem
What happens to the levels of TSH, T4, and T3 in secondary hyperthyroidism?
↑TSH, ↑T4 and T3
Which condition is characterized by low TSH and high T3 levels?
T3 toxicosis
Which of the following is true about subclinical hypothyroidism?
TSH is high and T4 and T3 are normal
Which of the following is a characteristic of subclinical hyperthyroidism?
TSH is low and T4 and T3 are normal
What is the significance of changes in TSH level in the blood in early forms of hypo and hyperthyroidism?
It serves as an early warning sign for intervention
Which antibody can be tested in Graves disease?
TSI
Which antibody can be tested in Hashimoto's thyroiditis?
TgAb
When should thyroid ultrasound be performed?
In all patients with a suspected thyroid nodule or goiter on physical examination or with nodules incidentally noted on other imaging studies like carotid doppler or CT scan
What can thyroid ultrasound assess?
All of the above
What is the advantage of ultrasound in thyroid assessment?
All of the above
Which antibody is tested in Graves disease?
TSI
Which antibody is tested in Hashimoto's thyroiditis?
TPO antibody
Which antibody is NOT associated with either Graves disease or Hashimoto's thyroiditis?
TgAb
Which antibody is tested in Hashimoto's thyroiditis?
TgAb
Which antibody is NOT associated with Graves disease?
TgAb
Which antibody is tested in Graves disease?
TSI
Which imaging technique uses a radiotracer absorbed by the thyroid gland to assess its functional status?
Thyroid scintigraphy
What is the normal value of thyroid uptake in thyroid scintigraphy?
15 to 25%
Which imaging technique is limited to the neck and cannot assess lesions below the sternum?
Ultrasound
Which imaging technique is painless, quick, and can be used during pregnancy?
Ultrasound
Which imaging technique can identify posteriorly located nodules or predominantly cystic nodules?
Ultrasound
Which type of thyroid nodule is characterized by increased absorption of radiotracer and is most likely a toxic adenoma?
Hot nodule
What is the functional status of a nodule that appears pale compared to the surrounding thyroid tissue in a thyroid scan?
Cold nodule
What percentage of cold thyroid nodules are malignant?
5-8%
Which condition is characterized by the whole thyroid gland appearing darker than the normal thyroid tissue in a thyroid scan?
Graves disease
Which type of thyroid nodule might require a thyroid biopsy to rule out cancer?
Cold nodule
Test your knowledge of the Hypothalamus-Pituitary-Thyroid Axis and its role in regulating thyroid hormone secretion. Explore the relationship between TRH, TSH, and thyroid hormones T3 and T4. Understand the mechanism of negative feedback control.
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