Thyroid Gland

Question 1

What are the functions of the thyroid hormones?

Answer 1

• increase oxygen consumption
• increase metabolism of proteins, fats & carbs
• promote normal growth
• required for normal CNS function

Question 2

What are the thyroid hormones ?

Answer 2

• Thyroxine (T4)
• Tri-iodothyronine (T3)

Question 3

Where is T4 converted into T3 ?

Answer 3

T4 is readily converted into T3 in most tissues, particularly the liver

Question 4

What are the thyroid hormone binding proteins ?

Answer 4

• thyroxine binding globulin - 70%
• albumin - 20%
• pre-albumin - 10%

Question 5

How are the thyroid hormones regulated ?

Answer 5

• negative feedback control of T4 & T3
• Free T3/T4 determines feedback
• thyroid stimulating hormone and thyroid releasing hormone involved in feedback

Question 6

What does TSH stand for ?

Answer 6

thyroid stimulating hormone

Question 7

What does TRH stand for ?

Answer 7

thyroid releasing hormone

Question 8

What is the reference range of plasma TSH ?

Answer 8

0.3 - 30 mU/L

Question 10

What is the incidence rate of hypothyroidism ?

Answer 10

2.0% female
0.2% male

Question 11

Define hypothyroidism

Answer 11

under active thyroid gland

Question 12

What are the primary causes of hypothyroidism ?

Answer 12

• Hashimoto’s thyroiditis
• anti-thyroid drugs
• iodine deficiency
• congenital hypothyroidism

Question 13

What is a secondary cause of hypothyroidism ?

Answer 13

• pituitary/hypothalamic defect

Question 14

What are the clinical features of hypothyroidism ?

Answer 14

weight gain
puffy face/hands/feet
bradycardia
cold intolerance
reduced appetite

Question 15

How can you manage hypothyroidism ?

Answer 15

• replacement therapy with T4
• Monitory of therapy with TSH

Question 16

What’s the incidence of hyperthyroidism ?

Answer 16

1% female
0.1% male

Question 17

Define hyperthyroidism

Answer 17

overactive thyroid gland

Question 18

What are some common causes of hyperthyroidism ?

Answer 18

• graves disease
• toxic nodules
• thyroid hormone intake

Question 19

What are some rare causes of hyperthyroidism ?

Answer 19

• ectopic thyroid tissue
• ash secreting tumours

Question 20

What are the clinical features of hyperthyroidism ?

Answer 20

• weight loss
• increased sweating
• tachycardia
• heat intolerance
• menstrual abnormalities

Question 21

How can hyperthyroidism be managed ?

Answer 21

• anti thyroid drugs = carbimazole
• radioiodine therapy - 131 I therapy
• thyroidectomy