Hypothyroidism

Question 1

What are the causes of Primary Hypothyroidism?

Answer 1

• Hashimoto’s thyroiditis (most commonin developed wrold)
• Primary atrophic hypothyroidism
• Iodine deficiency (most common worldwide)
• Post thyroidectomy/radioiodine tx
• Drug induced
  
  • Carbimazole
  • Prophylthiouracil
  • Lithium
  • Amiodarone
• de Quervain’s Thyroiditis

Question 2

What are the causes of secondary Hypothyroidism? (central hypothyroidism)

Answer 2

• Hypopituitarism (very uncommon)
  
  • Sheehan syndrome
  • tumours
  • infection
  • radiation

Question 3

What causes tertiary hypothyroidism?

Answer 3

• Trauma or lesion at hypothalamus
  
  • affects production of TRH

Question 4

What demographic of patients hypothyroidism commonly affects?

Answer 4

• Female
• 40 years or more

Question 5

What are the Sx of hypothyroidism?

Answer 5

• Tiredness
• Sleepy
• Lethargic
• Low mood
• Cold disliking
• Weight gain
• consipation
• menorrhagia
• hoarse voice
• decrease memory
• myalgia
• cramps/weakness

Question 6

What are the clinical signs of hypothyroidims?

*remember mnemoni bRADYCARDIC

Answer 6

• Reflexes - slow
• Ataxia
• Dry brittle hair, skin
• Yawning
• Cold hands
• Ascites
• Round puffy face
• Defeated demeanour
• Immobie
• CCF

Question 7

What are the Ix interpretation for Hypothyroidism?

Answer 7

• Primary Hypothyroidism
  
  • TSH: high
  • T4&T3: low
• Secondary Hypothyroidism
  
  • TSH: low
  • T4&T3: low

Question 8

What other diseases is seen associated with Hypothyroidism?

Answer 8

• If autoimmune cause - think other autoimmune disease
  
  • T1DM
  • Addison’s disease
• Turner’s, Downs
• CF
• Primary Biliary cholangitis
• POEMS syndrome

Question 9

How would you Mx Hypothyroidism?

Answer 9

• Levothyroxine
  
  • 1.6mcg/kg/day for <65
  • 25-50mcg/day for 65 and >

Question 10

What is the Cx of Hypothyroidism?

Answer 10

• Myxoedema Coma

Question 11

What is the Wolff-Chaikoff effect?

Answer 11

1. Too much iodine
2. Iodine inhibits thyroid hormone production (initially)
3. Eventually, thyroid will resume production

Question 12

What is the Px of Hashimoto’s Thyroiditis?

Answer 12

1. anti-TPO and antithyroglobulin antibodies infiltrate thyroid
2. Causes goitre initially
3. Atrophy later on

Question 13

What gene is associated with Hashimoto’s thyroiditis?

Answer 13

• HLA-DR3

Question 15

What is subclinical hypothyroidism?

Answer 15

• TSH >4mU/L
• T4&T3 normal
• no sx

Question 16

What age group does subclinical hypothyroidism typically affects?

Answer 16

• >55

Question 17

How would you Mx subclinical hypothyroidism?

Answer 17

• confirm raised TSH persistent (recheck in 2-4months)
• recheck sx of hypothyroidims

Question 18

What is the presentation of Myxedema Coma?

Answer 18

• A reduced level of consciousness
• Seizures
• Hypothermia
• Features of hypothyroidism

Question 19

What is sick euthyroid syndrome?

Answer 19

• condition in which serum levels of thyroid hormones are low with nonthyroidal systemic illness.
• Common in hospital inpatients
• T3 is particularly low in these patients