Thyroid

Question 1

What are the two main thyroid hormones produced by the thyroid gland?

Answer 1

Thyroxine (T4) and Triiodothyronine (T3)

T4 is the inactive form, while T3 is the active form that regulates metabolism.

Question 2

What is the inactive form of thyroid hormone?

Answer 2

Thyroxine (T4)

T4 acts as a prohormone and is converted to T3 in peripheral tissues.

Question 3

What is the active form of thyroid hormone?

Answer 3

Triiodothyronine (T3)

T3 is responsible for regulating the body’s metabolism.

Question 4

How is iodine absorbed for thyroid hormone production?

Answer 4

Iodine is absorbed from food and enters the thyroid gland via the sodium-iodine symporter.

This process is crucial for the synthesis of thyroid hormones.

Question 5

What is thyroglobulin?

Answer 5

A protein rich in tyrosine produced by the thyroid gland

It serves as a precursor for the formation of thyroid hormones.

Question 6

What is the process of iodine binding to thyroglobulin called?

Answer 6

Iodination

This process leads to the formation of MIT (mono-iodotyrosine) and DIT (di-iodotyrosine).

Question 7

What does MIT + DIT equal?

Answer 7

T3

MIT represents mono-iodotyrosine and DIT represents di-iodotyrosine.

Question 8

What does DIT + DIT equal?

Answer 8

T4

DIT is di-iodotyrosine, which combines with itself to form T4.

Question 9

How are T3 and T4 stored in the thyroid gland?

Answer 9

In the form of colloid

They are released into the bloodstream upon stimulation by TSH.

Question 10

What hormone does the hypothalamus release to regulate thyroid hormones?

Answer 10

Thyrotropin-Releasing Hormone (TRH)

TRH stimulates the pituitary to release TSH.

Question 11

What is the role of Thyroid-Stimulating Hormone (TSH)?

Answer 11

Stimulates the thyroid gland to produce and release T3 and T4

TSH is crucial for the regulation of thyroid hormones.

Question 12

What is the feedback mechanism for thyroid hormone regulation?

Answer 12

Negative feedback loop

High levels of T3 and T4 suppress TRH and TSH production, while low levels stimulate them.

Question 13

What is one function of thyroid hormones related to metabolism?

Answer 13

Increases basal metabolic rate (BMR)

This leads to increased energy consumption.

Question 14

How do thyroid hormones affect growth and development?

Answer 14

Essential for brain development in infants and growth in children

They play a crucial role in early life stages.

Question 15

What effect do thyroid hormones have on the cardiovascular system?

Answer 15

Increases heart rate and cardiac output

This enhances overall cardiovascular function.

Question 16

What is the effect of thyroid hormones on the gastrointestinal system?

Answer 16

Speeds up gut motility

This helps in digestion and nutrient absorption.

Question 17

How do thyroid hormones influence neuromuscular function?

Answer 17

Enhances reflexes and muscle function

This is important for physical activity and coordination.

Question 18

What role do thyroid hormones play in thermogenesis?

Answer 18

Helps maintain body temperature

This is crucial for homeostasis.

Question 19

How do thyroid hormones travel in the blood?

Answer 19

Bound to plasma proteins

Key transport proteins include Thyroid-binding globulin (TBG) and Albumin.

Question 20

Which forms of thyroid hormones are active in the body?

Answer 20

Free T3 and T4

Only the unbound forms exert biological effects.

Question 21

What happens to T3 and T4 levels in hypothyroidism?

Answer 21

T3 and T4 are low, leading to a slowed metabolism.

Question 22

What happens to TSH levels in primary hypothyroidism?

Answer 22

TSH is high.

Question 23

What does the pituitary gland do when it senses low T3 and T4?

Answer 23

Increases TSH to stimulate the thyroid.

Question 24

In secondary or tertiary hypothyroidism, what is the TSH level?

Answer 24

TSH is low or normal.

Question 25

What is the TFT pattern in primary hypothyroidism?

Answer 25

TSH: High, T3/T4: Low.

Question 26

What happens to T3 and T4 levels in hyperthyroidism?

Answer 26

T3 and T4 are high, leading to a fast metabolism.

Question 27

What happens to TSH levels in primary hyperthyroidism?

Answer 27

TSH is low.

Question 28

What does the pituitary gland do when it senses high T3 and T4?

Answer 28

Suppresses TSH production.

Question 29

What is the TFT pattern in primary hyperthyroidism?

Answer 29

TSH: Low, T3/T4: High.

Question 30

What is the active form of thyroid hormone?

Answer 30

T3.

Question 31

What is the inactive prohormone of thyroid hormone?

Answer 31

T4.

Question 32

How do T3 and T4 levels behave in most cases of thyroid disease?

Answer 32

Both follow the same trend (both low in hypothyroidism, both high in hyperthyroidism).

Question 33

What is T3 toxicosis?

Answer 33

A rare form of hyperthyroidism where only T3 is high.

Question 34

In primary hypothyroidism, what is the condition of the thyroid gland?

Answer 34

Underactive.

Question 35

In secondary hypothyroidism, what is the problem?

Answer 35

Problem in the pituitary gland (less TSH).

Question 36

What is the condition of the thyroid gland in primary hyperthyroidism?

Answer 36

Overproduces hormones.

Question 37

What is the rare condition associated with secondary hyperthyroidism?

Answer 37

TSH-secreting pituitary adenoma.

Question 40

What is the main goal in the management of hypothyroidism?

Answer 40

To replace the missing thyroid hormones

Question 41

What is the first-line treatment for hypothyroidism?

Answer 41

Levothyroxine (T4)

Question 42

What is the starting dose of Levothyroxine for hypothyroidism?

Answer 42

Usually 50–100 mcg once daily

Question 43

How often should the dose of Levothyroxine be adjusted based on TSH levels?

Answer 43

Every 6–8 weeks

Question 44

What is the target TSH level range for managing hypothyroidism?

Answer 44

Typically 0.4–4.0 mU/L

Question 45

How often should TFTs be monitored once stable in hypothyroidism management?

Answer 45

Every 6–12 months

Question 46

What special consideration should be taken for pregnant patients with hypothyroidism?

Answer 46

Levothyroxine requirements increase during pregnancy; close monitoring is essential

Question 47

What starting dose of Levothyroxine is recommended for the elderly or those with cardiovascular disease?

Answer 47

Start with a lower dose (e.g., 25 mcg/day)

Question 48

What is the main goal in the management of hyperthyroidism?

Answer 48

To reduce excess thyroid hormone production and address the underlying cause

Question 49

What are the first-line treatments for hyperthyroidism?

Answer 49

Antithyroid drugs and beta-blockers

Question 50

What is the most commonly used antithyroid drug?

Answer 50

Carbimazole

Question 51

What is the starting dose for Carbimazole?

Answer 51

15–40 mg daily

Question 52

What alternative antithyroid drug is used in the first trimester of pregnancy?

Answer 52

Propylthiouracil (PTU)

Question 53

What is a 'block and replace' regimen in hyperthyroidism management?

Answer 53

High-dose carbimazole is used to suppress the thyroid, followed by levothyroxine to normalize hormone levels

Question 54

What is the purpose of beta-blockers in hyperthyroidism management?

Answer 54

Used for symptom control (e.g., tachycardia, tremor, anxiety)

Question 55

What is an example of a beta-blocker used in hyperthyroidism?

Answer 55

Propranolol 40–80 mg TDS

Question 56

What is the definitive treatment for hyperthyroidism?

Answer 56

Radioiodine therapy and surgery (thyroidectomy)

Question 57

What is the mechanism of radioiodine therapy?

Answer 57

A single dose of radioactive iodine to destroy overactive thyroid tissue

Question 58

What are the risks associated with thyroidectomy?

Answer 58

Hypothyroidism, hypoparathyroidism, and recurrent laryngeal nerve injury

Question 59

What special consideration should be taken for Graves' disease?

Answer 59

May require long-term carbimazole or definitive treatment (radioiodine or surgery)

Question 60

What is the management for thyroid storm?

Answer 60

High-dose beta-blockers, high-dose carbimazole/PTU, steroids, supportive care

Question 61

What is the treatment for myxedema coma?

Answer 61

IV levothyroxine or liothyronine (T3) and IV hydrocortisone if adrenal insufficiency suspected

Question 62

Fill in the blank: The starting dose of Carbimazole is _______.

Answer 62

15–40 mg daily

Question 63

True or False: Levothyroxine should not be monitored after stabilization in hypothyroidism management.

Answer 63

False

Question 64

What supportive care is provided in the management of myxedema coma?

Answer 64

Warming, fluids, correction of electrolytes

Question 66

What is Graves' disease?

Answer 66

An autoimmune thyroid disease where the body produces IgG antibodies to the TSH receptor ## Footnote It is the most common cause of thyrotoxicosis and is typically seen in women aged 30-50 years.

Question 67

What are typical features of thyrotoxicosis?

Answer 67

Increased metabolic rate, weight loss, heat intolerance, palpitations, anxiety ## Footnote These features are common across various causes of thyrotoxicosis.

Question 68

What specific eye signs are seen in Graves' disease?

Answer 68

Exophthalmos, ophthalmoplegia ## Footnote Eye signs are present in about 30% of patients.

Question 69

What is pretibial myxoedema?

Answer 69

A specific sign of Graves' disease characterized by swelling and thickening of the skin over the shins ## Footnote It is one of the unique features of Graves' disease.

Question 70

What is thyroid acropachy?

Answer 70

A triad of symptoms including digital clubbing, soft tissue swelling of the hands and feet, periosteal new bone formation ## Footnote This condition is associated with Graves' disease.

Question 71

What are TSH receptor stimulating antibodies?

Answer 71

Antibodies found in 90% of patients with Graves' disease that stimulate the TSH receptor ## Footnote These are critical in the pathogenesis of the disease.

Question 72

What percentage of patients with Graves' disease have anti-thyroid peroxidase antibodies?

Answer 72

75% ## Footnote These antibodies are also present in other autoimmune thyroid diseases.

Question 73

What does thyroid scintigraphy show in Graves' disease?

Answer 73

Diffuse, homogenous, increased uptake of radioactive iodine ## Footnote This finding helps to differentiate Graves' disease from other causes of thyrotoxicosis.

Question 74

Fill in the blank: Graves' disease is the most common cause of _______.

Answer 74

thyrotoxicosis

Question 75

True or False: Ophthalmoplegia is a common feature of all causes of thyrotoxicosis.

Answer 75

False ## Footnote Ophthalmoplegia is specific to Graves' disease.