Exam 1-- Pt 4 Thyroid

Question 1

T/F. A goiter is indicative of hyperthyroidism.

Answer 1

False– possible to have a goiter and be hypothyroid, euthyroid, or hyperthyroid

Question 2

What is intolerance to heat, bulging eyes (exopthalmos), weight loss, increase diarrhea, and tachycardia symptoms of?

Answer 2

hyperthyroidism

Question 3

Thyroid hormones are orally active, and consumption of thyroid tissue can cause what?

Answer 3

thyrotoxicosis (a form of hyperthyroidism)

• sleeplessness, nervousness, headache, fatigue, excessive sweating, weight loss

Question 4

The thyroid sequesters what ion very well? Therefore, what can be used to treat hyperthyroidism and why?

Answer 4

iodide; use radioactive iodine b/c it can destroy secretory cells (but this may cause ind to end up hypothyroid which would then require replacement therapy)

Question 5

What is an enlargement of the thyroid gland? What does the size of the gland depend on?

Answer 5

goiters; depends on TSH stimulation

Question 6

T/F. It is possible to have a goiter and be hypothyroid, euthyroid, or hyperthyroid.

Answer 6

True

Question 7

What is an example of a Euthyroid goiter? How does this occur?

Answer 7

dietary iodine deficiency (MC cause of a goiter)

1. synthesis of thyroid hormones decreases and gladular T4 (T3) secretion decreases
2. NOW pituitary TSH synthesis and secretion increases
3. TSH stimulates growth and vascularity of thyroid
4. thyroid enlarges =goiter

Question 8

What is an example of a hyperthyroid goiter?

Answer 8

1. Grave’s Disease

2. Thyroid Adenoma (tumor)

Question 9

Describe how a goiter occurs in Grave’s Disease.

Answer 9

1. thyroid stimulated by abnormal antibodies that form against the TSH receptor (known as thyroid-stimulating immunoglobulins–TSIs)
2. gland hypertrophies (goiter)
3. TSIs mimics TSH and stimulates synthesis and secretion of thyroid hormones (hyperthyroid)

Question 10

T/F. TSIs (thyroid-stimulating immunoglobulins) have a 12x lesser effect than TSH.

Answer 10

False– TSIs have a 12x longer stimulating effect over TSH

therefore high thyroid hormone levels inhibits TSH formation by anterior pituitary and therefore TSH levels are decreased

Question 11

Describe how a goiter occurs from a Thyroid Adenoma.

Answer 11

secretes large quantities of thyroid hormone

- rest of thyroid is inhibited due to negative feedback inhibition of TSH from the anterior pituitary

Question 12

What does iodine deficiency beginning in utero result in?

Answer 12

endemic cretinism

Question 13

What is Cretinism?

Answer 13

• caused by extreme hypothyroidism during fetal life, infancy, or childhood
• loose term applied to all forms of hypothyroidism beginning before or at birth
• characterized by failure of body growth and intellectual development disorder

Question 14

In Cretinism, is skeletal growth or soft tissue growth more inhibited?

Answer 14

skeletal growth

Question 15

What is the treatment for Cretinism?

Answer 15

Tx with iodine or thyroxine

- sooner is better than later to prevent intellectual development disorder

Question 16

What is an autoimmune disorder that destroys the thyroid gland? What precedes it?

Answer 16

Hashimoto’s disease (AKA chronic lymphocytic thyroiditis); preceded by thyroiditis (inflammation)

overtime goiter may develop

Question 17

What is the MC cause of hypothyroidism in the US?

Answer 17

Hashimoto’s Disease (aka chronic lymphocytic thyroiditis)

Question 18

What is muscle stiffness/sluggishness, constipation, decrease hair growth, intolerance to cold all characteristics of?

Answer 18

hypothyroidism

Question 19

What is 3,3’,5’-triiodothyronine?

Answer 19

reverse T3 (rT3) which is inactive 
(recall--T3 = 3,3',5 triiodothyronine)

Question 20

What produces rT3?

Answer 20

Deiodinase type I and type III

Question 21

What ratio can be looked at for diagnosis of tissue cell hypothyroidism?

Answer 21

free T3 vs reverse T3 ratio

Question 22

What can block the pathway to produce T3 and instead produce rT3?

Answer 22

stressssssss

Question 23

What antithyroid substance decreases iodide trapping by competitive inhibition and decreases iodination of thyroglobulin?

Answer 23

Thiocyanate

- this will therefore decrease thyroid hormone production

Question 24

What is the end results of Thiocyanate?

Answer 24

decreases thyroid hormone production

Question 25

What antithyroid substance decreases thyroid hormone function by blocking peroxidase enzyme? What is the affect?

Answer 25

Propylthiouracil

therefore increasing TSH and could lead to a goiter

Question 26

What affect do high blood concentrations of inorganic iodides have?

Answer 26

• inhibit most aspects of thyroid function

- frequently given 2-3 weeks prior to removal of thyroid to minimize bleeding from the surgery

Question 27

What is the term for severe hypothyroidism during fetal development or early childhood associated with intellectual development disorder?

Answer 27

Cretinism

Question 28

What is the term for hyperthryoid Exophthalmos, lid lag, upper lid retraction, extraocular muscle weakness..etc?

Answer 28

Graves Disease

Question 29

What is the term for acute inflammation of the thyroid (likely the result of a viral inf.)?

Answer 29

Subacute Thyroiditis

Question 30

What is the term for an autoimmune disorder that destroys the thyroid in adults?

Answer 30

Hashimoto’s Thyroiditis

Question 31

What is the term for when the tissue is exposed to excessive amounts of thyroid hormones? What is the most prevalent form?

Answer 31

Thyrotoxicosis

Graves Disease is most prevalent form

Question 32

What is the term for generalized nonpitting edema seen with hypothyroidism?

Answer 32

Myxedema

there is accumulation of GAGs in interstitial spaces–> therefore retains fluid