Patho: Thyroid

Question 1

What secretes T4 & T3?

Answer 1

Follicular cells

Question 2

Which is the metabolically form of thyroid hormones & describe it’s formation.

Answer 2

T3
T4 converted to T3 in the circulation via de-ionisation

Question 3

Name the 4 congenital diseases of thyroid that you learnt

Answer 3

1. Thyroglossal duct cyst
2. Abnormal development of thyroid gland
3. Ectopic thyroid tissue (upper GIT, URT, soft tissues of neck, CVS)
4. Thyroid dyshormonogenesis

Question 4

What is thyroid dyshormonogenesis & how does it present clinically?

Answer 4

• Congenital, inherited
• HYPOthyroidism (defects in thyroid hormone synthesis)
• Goitre present
• Clinical: Mental and growth retardation

Question 5

What causes thyroglossal duct cyst?

Answer 5

• Cx: Infection, malignant change (rare)
• Embryonal vestige (degenerated remnants from embryo)

Question 6

How does abnormal development of thyroid gland manifest?

Answer 6

Underdeveloped thyroid cos of aplasia, hypoplasia –> HYPOthyroidism in infancy/early childhood –> low BMR

Clinical presentations:
1. Cretinism: severe intellectual disability, short stature
2. Coarse facial features. protruding tongue, umbilical hernia

Question 7

What is simple/diffuse vs multinodular goitre?

Answer 7

Simple/diffuse nontoxic goitre = general enlargement without hyperfunctioning (due to hypertrophy and hyperplasia of follicular cells)

Multinodular goitre = multiple nodules

Simple –> recurrent hyperplasia and involution –> MNG