Thyroid Dysfunction Flashcards Preview

MS2 - Digestive, Endocrine, and Metabolic Systems > Thyroid Dysfunction > Flashcards

Flashcards in Thyroid Dysfunction Deck (14)
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1
Q

Which deiodinase deactivates T4?

A

Type 3 deiodinase (which creates reverse T3)

2
Q

What can promote a shift to type 3 deiodinase?

A
Starvation
Severe illness
Neonatal period
Stress
Glucocorticoids
Propranolol
Amiodarone
Radiocontrast dyes
3
Q

What percent of T4 is free?

A

0.02%

4
Q

Decreased thyroid binding proteins can cause ___________.

A

hypothyroidism

5
Q

The normal range of TSH is _____________.

A

0.4 - 4.0 (treat if greater than 10)

6
Q

What is the best test for thyroid dysfunction?

A

TSH (provided the pituitary does not show other signs of dysfunction)

7
Q

_______________ leads to an increased expression of NIS.

A

TSH (NIS is Na-Iodide Symporter)

8
Q

Thyrotoxicosis presents with _________________.

A

low TSH and high T3/T4

9
Q

If TSH is low but the thyroid is still taking up iodide, then this is ________________.

A

true hyperthyroidism, characterized by the autonomous production of thyroid hormone

10
Q

Deposition of hyaluronic acid in the anterior calves leads is called ____________ and is pathognomonic for Graves’ disease.

A

pretibial myxedema

11
Q

The activating deiodinases are _________.

A

types I and II

12
Q

What lab pattern is suggestive of subclinical hyperthyroidism?

A

Low TSH
Normal T4
Normal T3

(Similarly, subclinical hypothyroidism presents with elevated TSH but normal T4 and T3.)

13
Q

Which cell type mediates the damage in Hashimoto’s?

A

Lymphocytes

14
Q

Iodine uptake will be low in which types of hyperthyroidism?

A
  • Factitious
  • Struma ovarii
  • All the disorders that damage the thyroid (viral, onset of Hashimoto’s, autoimmune)

Decks in MS2 - Digestive, Endocrine, and Metabolic Systems Class (133):