Endocrine 3

Question 1

What does Hypothyroidism result from?

Answer 1

Results from a functional failure of the thyroid gland and its inability to meet the body’s demands for Thyroxine (T4) and Triidiothyronine (T3)

Question 2

What are the 4 most important causes of hypothyroidism

Answer 2

1. Developmental defects (congenital thyroid aplasia)
2. Inflammation of the thyroid (Hashimotos)
3. Thyroidectomy
4. Iodine deficiency

Question 3

Congenital thyroid aplasia (no development of the thyroid) is found in ____ in ______ newborns

Answer 3

1 in 4000 newborns

Question 4

Inflammation of the thyroid is most often ______-mediated and includes several disorders such as Hashimoto Thyroiditis

Answer 4

immune-mediated

Question 5

What is Hashimoto Thyroiditis characterized by?

Answer 5

gradual failure because of an immune destruction of the thyroid gland.

Question 6

Is Hashimoto thyroidits more common in men or women and what ages is it most prevalent between?

Answer 6

More common in Women

most prevalent b/w 45 and 65 y/o

Question 7

Which disorder causes a painless, diffuse, enlargement of the thyroid.

Answer 7

Hashimoto Thyroiditis

Question 8

**Patients with Hashimoto Thyroidits are at an increased risk for the development of what?

Answer 8

**B-cell Lymphomas (30-40x)

(this will be a question)

Question 9

Which disorder?

Histologically, there is extensive infiltration of the follicles and stroma with mononuclear infiltration including lymphocytes, and plasma cells which destroy the thyroid follicles and well-developed germinal centers

Subsequent healing and fibrosis may actually reduce the size

Answer 9

Hashimoto Thyroiditis

Question 10

Which of the main causes of hypothyroidism causes an iatrogenic hypothyroidism, usually for removal of a tumor of the thyroid.

Answer 10

Thyroidectomy

Question 11

Which of the 4 main causes of hypothyroidism is rare in western countries due to iodine being preventively added to the salt

Answer 11

Iodine deficiency

Occurs if the food or water does not contain adequate amounts of Iodine so hypothyroidism may occur.

Question 12

The deficiency of iodine in food or water is usually associated with ________ of the thyroid gland (goiter).

Answer 12

nodular enlargement

Question 13

Which state in the US had an increased prevalence of thyroid goiters before iodized salt?

Answer 13

Michigan (b/c it is surrounded by fresh water)

Question 14

What happens to the follicles in iodine deficiency because the thyroid can’t synthesize enough T3 and T4? Why does it do this?

Answer 14

follicles undergo compensatory hyperplasia in an attempt to increase the production of hormones.

Question 15

What disorder is this and what is it due to?

Answer 15

Goiter due to iodine deficiency

Question 16

What would thyroid labs of a person with iodine deficiency look like?

Answer 16

Elevated TSH,

Low T3/T4 (b/c you have to have iodine and tyrosine to make active T3/T4)

Question 17

Iodine deficiency- what do low concentrations of T3 and T4 in the serum result in?

Answer 17

• results in inadequate feedback inhibition of the pituitary, which responds to the low levels of thyroid hormones by overproducing TSH.
• TSH stimulation without adequate supplies of iodine further promotes the enlargement of the thyroid, but cannot correct the hormone deficiency.

Question 18

The sxs of hypothyroidism depend on what?

Answer 18

The age of the patient

Question 19

what do sxs of hypothyroidism look like in children?

Answer 19

The deficiency affects:

1. growth of the entire body (dwarfism)
2. the development of the CNS- mental development is retarded (cretinism)

Question 20

What 2 things does hypothyroidism in a child cause if the thyroid deficiency is not recognized?

Answer 20

1. Dwarfism
2. Cretinism (mental development is retarded)

Question 21

Hypo or hyperthyroidism?

1. Myxedema
2. Slows down function of organs
3. Sleepy
4. Lacks mental alertness
5. Tires easily
6. Lacks endurance

Answer 21

Hypothyroidism in adults

Question 22

What is the name of the following physical exam finding and what condition is it found in?

Answer 22

Name: Myxedema (skin is edematous, dough-like and puffy)

seen in hypothyroidism in adults

Question 23

Hyper or hypothyroidism?

1. Slows down organs:
   
   1. bradycardia
   2. Constipation (intestines lose motility)
   3. skeletal muscles are weak, stiff and ache.

Answer 23

Hypothyroidism

Question 24

What is the diagnosis of hypothyroidism based on?

Answer 24

biochemical measurements of thyroid hormones in the circulation

low T3/T4

elevated TSH

Question 25

How is hypothyroidism treated?

Answer 25

synthetic thyroid hormones (synthroid)- usually great results but usually must be taken for the rest of their life

Question 26

What are the 4 causes of a nodular goiter?

Answer 26

1. Graves Disease

2. Iodine deficiency
3. neoplasia
4. Idiopathic (cause is unknown)–> this is most often the cause

“GIIN”

Question 27

What do nodular goiters consist of?

Answer 27

nodules that enlarge and deform the thyroid

Question 28

Histologically, what do the nodules of nodular goiters consist of?

Answer 28

consist of thyroid follicles that vary in size and shape and are usually filled with colloid.

Question 29

Nodular goiter:

Between the nodules, the stroma consists of ______ and _______infiltrated with lymphs and macrophages.

Answer 29

Vessels and collagen fibers

Question 30

Clinically, most goiters are ______

Answer 30

Euthyroid

(do not cause hyper or hypothyroidism)

Question 31

What are sxs of nodular goiters and what do they result from?

Answer 31

-coughing

-hoarsness

sxs related to the compression of adjacent structures (i.e. larynx or recurrent laryngeal nerve)