Hyperthyroidism and Hypothyroidism

Question 1

Causes of thyrotoxicosis

Answer 1

• Toxic nodular
  
  • Grave’s disease
  • Iodine induced

Question 2

What is Grave’s Disease

Answer 2

○ Autoimmune mediated (Type II)

• Thyroid stimulating immunoglobuin (TSI) binds and stimulates the TSH receptor OR
• Thyroid growth-stimulating immunoglobulin’s-binds and stimulates TSH receptor OR
• TSH-binding inhibitor immunoglobulin- stimulates or inhibits TSH receptor (can develop or present with hypothyroidism)

Question 3

What is the differential for hyperthyroidism sx?

Answer 3

Graves 
Toxic Nodule 
Iodine induced: radiographic contrast 
Drugs: amiodarone, thyroxine 
Thyroiditis

Question 4

What tests are done to diagnose hyperthyroidism?

Answer 4

• TSH
  
  • FT4 and/or FT3 are elevated
  • Consider a scan
  • Anti-TSH receptor Ab

Question 5

Why is it helpful to do a thyroid scan in hyperthyroidism?

Answer 5

Helps us distinguish between Grave’s, toxic nodular disease, iodine or thyroiditis-induced thyrotoxicosis and factitious cause

Question 6

What will be see on a thyroid scan in Graves Disease?

Answer 6

Homogeneous increase uptake

Question 7

What will be see on a thyroid scan in multinodual goitre?

Answer 7

Heterogenous

One area will uptake more than the other

Question 8

What is the treatment for hyperthyroidism?

Answer 8

Carbimazole
Propylthiouracil
Radioactive iodine
Surgery (rare)

Question 9

When is propylthiouracil used over carbimazole?

Answer 9

used in the first trimester of pregnancy

Question 10

When is surgery done for hyperthyroidism?

Answer 10

adverse reaction to drugs, cosmetic/patient preference, risk of malignancy

Question 11

What are the primary causes of hypothyroidism?

Answer 11

Hashimoto's
Iodine deficiency 
Drugs: lithium, amiodarone
Thyroidectomy 
Thyroiditis 
Congenital 
Hypopituitarism

Question 12

What is Hashimoto’s?

Answer 12

Type IV hypersensitivity

Breakdown of tolerance to thyroid tissues, causing damage by CD8+ cell mediated death

Question 13

How do we investigate hypothyroidism?

Answer 13

• TSH, free T4, T3
• Anti-thyroid Ab (anti-thyroid peroxidase - TPO)
• Consider a thyroid US only if there is a palpable goitre

Question 14

What is the treatment for hypothyroidism?

Answer 14

• Thyroxine T4 replacement

Question 15

What would you expect to see O/E in hypothyroidism?

Answer 15

• Goitre
• Decreased sympathetic drive: Bradycardia, hypotension, angina
• Reduced reflexes: delayed tendon reflexes
• Myxoedema, hoarse voice, myopathy
• Proximal myopathy

Question 16

What would you expect to see O/E in hyperthyroidism?

Answer 16

SNS increased: Elevated HR, palpitations, cardiomegaly, tremor, lid lag
Hypereflexia
Skin, nail and hair changes
Thyroid size, consistency, bruit
Eyes: redness/irritation, staring appearance, mild double vision on the right extreme gaze.
Exophthalmia

Question 17

What would you see O/E specifically in Grave’s disease?

Answer 17

Exophthalmos
Opthalmoplegia
Thyroid stare
Lid lag
Pretibial myxedema
Acropathy