Thyroid Disorders

Question 1

Quick recap of function of Thyroid hormones?

Answer 1

• Raises metabolic rate & promotes thermogenesis
• Increases Gluconeogenesis
• Increases Proteolysis
• Increases Lipolysis
• Stimualtes GH receptor expression
• Foetal Brain Development
• Sensitizes B2 receptors to epinephrine (Permissive)

Question 2

What are some causes of hyperthyroidism?

Answer 2

• Thyroid adenoma

- Graves Disease

Question 3

What is graves disease?

Answer 3

Antibodies mimic TSH, causing continuous stimulation of the Thyroid gland

Question 4

Whats the presentation of hyperthyroidism?

Answer 4

Think about the effects of T3:

• Weight loss
• Heat intolerance
• Muscle weakness

Alters NS function:
- Hyperreflexia & Psychological disturbance

Elevates Cardiovascular function:
- Tachycardia/contraction strength –> high output –> Eventual cardiac failure

Question 5

How do Thyroid hormones affect cardiovascular function?

Answer 5

TH is permissive to epinephrine on beta receptors

So excess TH –> Greater action of epinephrine –> Greater HR & Contraction strength

Question 6

What could cause Hypothyroidism?

Answer 6

• Autoimmune (Hashimoto’s) hypothyroidism
• Dietary Iodine Deficiency
• Idiopathic

Question 7

Presentation of Hypothyroidism?

Answer 7

Actions of T3:

• Weight Gain
• Cold Intolerance
• Brittle Nails & Thin skin (disrupting protein synthesis)

Alters NS function:

• Hyporeflexia
• Fatigue
• Slow speech

Reduces CV function:

• Bradycardia
• Weak pulse

Question 8

What is Goitre?

Answer 8

A significantly & diffusely enlarged Thyroid gland (Causes a large visible swelling in the neck)

It can occur in both Hyper and Hypothyroidism

Question 9

By what mechanism does Goitre occur in hyperthyroisism?

Answer 9

Overactivity of the Thyroid.

Basically stimulation leads to hyperplasia

Question 10

By what mechanism does Goitre occur in hypothyroidism?

Answer 10

Lack of THs means TSH isn’t inhibited so excess TSH stimulates the thyroid gland causing the enlargement