Thyroid disorders

Question 1

What is the mechanism of thyroid hormone production?

Answer 1

Hypothalamus secretes TRH. TRH stimulates A. pituitary gland to secrete TSH. TSH stimulates thyroid gland to secrete T3 triiodothyronine, T4 thyroxine. This causes negative feedback mechanism that relays to hypothalamus to not secrete TRH anymore.

Question 2

What is primary hypothyroidism and causes?

Answer 2

Failure of thyroid gland e.g. autoimmune hashimoto thyroiditis, thyroidectomy

Question 3

What is secondary hypothyroidism and causes?

Answer 3

Failure in hypothalamus/pituitary gland e.g. hypopituitarism (pituitary gland does not make enough hormones like TSH)

Question 4

What is subclinical hypothyroidism?

Answer 4

Mild form of hypothyroidism in which the patient is asymptomatic, TSH elevated, T4/T3 normal levels

Question 5

What is Hashimoto thyroiditis?

Answer 5

Autoimmune mediated destruction of thyroid gland, cause of primary hypothyroidism.

Question 6

Symptoms of hypothyroidism?

Answer 6

Bradycardic
Reflexes slow
Ataxia
Dry thin hair/skin
Yawning/fatigue
Cold hands
Ascites
Round face
Defeated demeanour
Immobile
Congestive cardiac failure
Weight gain

Painless englarged goitre

Question 7

What investigations and results would you expect to see in Hashimoto thyroiditis?

Answer 7

T3/T4 decreased
TSH raised
Antithyroid antibodies
TgAb and TPOAb raised

Question 8

What is the management for hashimito thyroiditis?

Answer 8

Levothyroxine

Question 9

What is the CI for levothyroxine?

Answer 9

Levothyroxine should be in low dose for coronary artery disease patients, it increases heart rate.

Question 10

What is Grave’s disease?

Answer 10

Autoimmune condition associated with hyperthyroidism

Question 11

What investigations and results would you expect to see in Graves Disease?

Answer 11

T3/T4 raised
TSH decreased
Antithyroid antibodies TRAb raised

Question 12

What is the management for Grave’s disease?

Answer 12

Carbimazole reduces amount of thyroid hormones produced in thyroid gland.

Question 13

What is the presentation of someone with Grave’s disease?

Answer 13

Heat intolerance (pyrexia), sweating, palpitations, weight loss, bulging eyes, goitre, lid lag.

Question 14

What condition can arise from Carbimazole use?

Answer 14

Agranulocytosis (acute lowering of the white cell count) , presents with sore throat or fever.