Pathology P.1107-1130: Thyroid And Parathyroid Glands

Front 1

What is thyrotropin?

Back 1

TSH

Front 2

TSH binds to what type of receptors to stimulate T3/T4 production in thyroid cells?

Back 2

G-protein (cAMP mechanism)

Front 3

Which thyroid hormone is more active?

Back 3

T3 is10x more active than T4

Front 4

How does T3 up-regulate metabolic activity?

Back 4

binds to nuclear receptors and complexes with retinoic acid and binds to the TRE (thyroid hormone response element) on DNA

Front 5

Goitrogens are used to treat what disorder?

Back 5

hyperthyroidism

Front 6

What does propylthiouracil do?

Back 6

inhibits TPO = less oxidation of iodide and less organification of thyroglobulin

Front 7

Why does iodide in large doses treat hyperthyroidism?

Back 7

prevents proteolysis of thyroglobulin = less thyroid hormone released into the blood

Front 8

Where is calcitonin made?

Back 8

C cells (parafollicular cells) of the thyroid gland

Front 9

A patient with an increased B-adrenergic tone and normal catecholamine levels most likely has what disorder?

Back 9

hyperthyroidism

Front 10

Weight loss is characteristic of which thyroid disorder?

Back 10

hyperthyroidism

Front 11

What is secondary hyperthyroidism?

Back 11

high levels of TSH causing high T3/T4 (very rare)

Front 12

A patient with hyperthyroidism will have (diarrhea or constipation)?

Back 12

diarrhea due to increase gut motility

Front 13

Apathetic hyperthyroidism is (more or less) severe than typical hyperthyroidism?

Back 13

less severe due to older patient population

Front 14

What is secondary hypothyroidism?

Back 14

low thyroid hormones due to pituitary or hypothalamic dysfunction (very rare)

Front 15

Most common cause of hypothyroidism worldwide?

Back 15

iodide deficiency

Front 16

Most common cause of hypothyroidism in America?

Back 16

Hashimoto's thyroiditis

Front 17

What is Pendred syndrome?

Back 17

defective pendrin = less iodide put into the colloid for T3/T4 synthesis. also deafness because pendrin is needed in the cochlea

Front 18

Lithium has what effect on thyroid function?

Back 18

decreases

Front 19

What is cretinism?

Back 19

congenital low thyroid hormones (or no thyroid gland). impaired physical and mental development

Front 20

A mother with untreated hypothyroidism may have a child born with what condition?

Back 20

cretinism. thyroid hormones need to be normal in a pregnant mother so that they can be used for normal development of a fetus (they cross the placental barrier)

Front 21

What is the main difference between Myxedema and Cretinism?

Back 21

myxedema in hypothyroidism in the adult. cretinism is in children

Front 22

Reduced cardiac output is characteristic of which thyroid disorder?

Back 22

hypothyroidism

Front 23

You suspect a patient has hypothyroidism. What would you expect to see in a lipid panel? Why?

Back 23

high LDL and total cholesterol due to decrease in LDL receptor synthesis by the liver

Front 24

Why is there non-pitting edema in hypothyroidism?

Back 24

more GAGs and hyaluronic acid ECM to hold water

Front 25

What is the most sensitive test to screen for primary hypothyroidism? What results would we expect if our patient had primary hypothyroidism?

Back 25

TSH is the most sensitive. TSH would be high if the patient had primary hypothyroidism due to loss of negative feedback

Front 26

Hashimoto's thyroiditis is more common in which gender?

Back 26

older females

Front 27

Hashimoto's thyroiditis may be caused by genetic defects in which immune mediating genes?

Back 27

CTLA4 and PTPN22

Front 28

What are Hurthle cells?

Back 28

eosinophilic granular cells lining atrophic thyroid cells in thyroiditis

Front 29

Goiter formation in Hashimoto's thyroiditis is usually (painless or painful)?

Back 29

painless

Front 30

Most common cause of thyroid pain?

Back 30

DeQuervian thyroiditis

Front 31

Graves disease is more common in which gender?

Back 31

female

Front 32

Most common cause of hyperthyroidism?

Back 32

Grave's disease

Front 33

Why do we see exopthalmos in Grave's disease?

Back 33

TSH receptors in the orbit stimulate fibroblasts. also edema due to T cell infiltration and muscle swelling, and fat deposition

Front 34

What would we expect to see in a thyroid function test on a Patient with Grave's disease?

Back 34

High T3/T4, low TSH/TRH

Front 35

Why might a diet high in Cassava root put an individual at risk for hypothyroidism?

Back 35

cassave contains thiocyanate which competitively inhibits iodine trapping = low T3/T4 formation

Front 36

What is Plummer's syndrome?

Back 36

toxic multi-nodular goiter. goiter from hypothyroidism produces another nodule in the goiter that produces more thyroid hormones and can even cause hyperthyroidism

Front 37

Which is more likely to be neoplastic? solitary nodule or multiple nodules?

Back 37

solitary nodule

Front 38

Which is more likely to be neoplastic? nodule in younger or older patients

Back 38

younger

Front 39

Which is more likely to be neoplastic? nodule in male or female patients

Back 39

male

Front 40

How can we differentiate a follicular adenoma form a carcinoma?

Back 40

capsular integrity. intact capsule = adenoma

Front 41

I don't feel like making flashcards for all these thyroid neoplasms

Back 41

they're all the same thing

Front 42

"Orphan Annie Eye" nuclei are characteristic of which thyroid neoplasm?

Back 42

papillary carcinoma

Front 43

Parathyroid hormone has what effect on calcium excretion by kidneys?

Back 43

decreases it

Front 44

Parathyroid hormone has what effect on phosphate excretion by kidneys?

Back 44

increases it

Front 45

Constantly elevated levels of PTH will lead to what disorders?

Back 45

hypercalcemia, osteoporosis

Front 46

Why are calcium levels elevated in solid tumors?

Back 46

they release PTHrP which activated RANKL on osteoblasts to make more osteoCLASTs to degrade bone to put calcium in the blood

Front 47

What is secondary hyperparathyroidism?

Back 47

low calcium levels in the blood cause a physiologic increase in PTH levels

Front 48

Most common cause of primary hyperparathyroidism?

Back 48

non-familial (sporadic) tumor of Parathyroid

Front 49

Most common cause of secondary hyperparathyroidism?

Back 49

renal failure leading to excess calcium loss

Front 50

What is tetany?

Back 50

neuromuscular irritability due to low calcium levels, seen in hypoparathyroidism

Front 51

A gain of function mutation in CASR would lead to what disorder?

Back 51

hypoparathyroidism. overactivity of CASR = more sensing of calcium levels in blood = suppression of PTH levels

Front 52

Positive Trosseau and Chvostek signs may indicate which endocrine disorder?

Back 52

hypoparathyroidism

Front 53

What is pseudohypoparathyroidism?

Back 53

normal PTH levels but inability of the cells to use it. PTH resistance