Endo Exam 3 Notes

Question 1

Hormones of HPT axis

Answer 1

TRH (hypothalamus), TSH (pituitary), T3/T4 (thyroid)

Question 2

Negative feedback in HPT axis

Answer 2

T3/T4 inhibit TRH and TSH release

Question 3

Main active thyroid hormone

Answer 3

T3

Question 4

Main circulating thyroid hormone

Answer 4

T4

Question 5

Role of sodium-iodide symporter

Answer 5

Active iodide uptake into follicular cells

Question 6

Role of thyroid peroxidase

Answer 6

Iodide oxidation, organification, coupling

Question 7

Role of thyroglobulin

Answer 7

Scaffold and storage for thyroid hormone synthesis

Question 8

Role of thyroxine-binding globulin

Answer 8

Transport T3/T4 in blood

Question 9

Cellular mechanism of thyroid hormones

Answer 9

Bind nuclear receptors → gene transcription

Question 10

Major physiologic effects of thyroid hormones

Answer 10

↑BMR, growth, CNS development, ↑cardiac output

Question 11

Definition of hyperthyroidism

Answer 11

Excess synthesis/secretion of thyroid hormones

Question 12

Most common cause of hyperthyroidism

Answer 12

Graves disease

Question 13

Pathogenesis of Graves disease

Answer 13

TSH-receptor–stimulating IgG antibodies

Question 14

Classic Graves triad

Answer 14

Hyperthyroidism, diffuse goiter, ophthalmopathy

Question 15

RAIU pattern in Graves disease

Answer 15

Diffuse increased uptake

Question 16

Iodine-induced hyperthyroidism mechanism

Answer 16

Jod-Basedow phenomenon

Question 17

Amiodarone thyroid effects

Answer 17

Type 1 increased synthesis, Type 2 destructive thyroiditis

Question 18

Life-threatening hyperthyroid complication

Answer 18

Thyroid storm

Question 19

Primary hypothyroidism definition

Answer 19

Thyroid gland failure

Question 20

Secondary hypothyroidism definition

Answer 20

Pituitary or hypothalamic failure

Question 21

Most common cause of hypothyroidism (iodine sufficient)

Answer 21

Hashimoto thyroiditis

Question 22

Hashimoto antibodies

Answer 22

Anti-TPO, anti-thyroglobulin

Question 23

Microscopy of Hashimoto thyroiditis

Answer 23

Lymphoid aggregates with germinal centers, Hurthle cells

Question 24

De Quervain thyroiditis 특징

Answer 24

Painful, post-viral, granulomatous

Question 25

Lymphocytic thyroiditis 특징

Answer 25

Painless, postpartum or sporadic

Question 26

Treatment of hypothyroidism

Answer 26

Levothyroxine

Question 27

Major adverse effect of excess levothyroxine

Answer 27

Iatrogenic hyperthyroidism

Question 28

Most common cause of congenital hypothyroidism

Answer 28

Thyroid aplasia or hypoplasia

Question 29

Untreated congenital hypothyroidism outcome

Answer 29

Cretinism

Question 30

Newborn screen finding in congenital hypothyroidism

Answer 30

High TSH, low T4

Question 31

Simple diffuse goiter cause

Answer 31

Chronic TSH stimulation

Question 32

Multinodular goiter pathogenesis

Answer 32

Long-standing uneven follicular hyperplasia

Question 33

Difference between toxic and nontoxic goiter

Answer 33

Presence of hyperthyroidism

Question 34

Why iodine deficiency causes goiter

Answer 34

Low T4 → high TSH → thyroid enlargement

Question 35

Thyroglossal duct cyst key feature

Answer 35

Midline neck mass moving with swallowing

Question 36

Lingual thyroid definition

Answer 36

Ectopic thyroid tissue at base of tongue

Question 37

Most common thyroid carcinoma

Answer 37

Papillary carcinoma

Question 38

Papillary carcinoma nuclear features

Answer 38

Orphan Annie nuclei, nuclear grooves, psammoma bodies

Question 39

Papillary carcinoma spread

Answer 39

Lymphatic

Question 40

Key diagnostic feature of follicular carcinoma

Answer 40

Capsular or vascular invasion

Question 41

Follicular carcinoma spread

Answer 41

Hematogenous

Question 42

Medullary carcinoma cell of origin

Answer 42

Parafollicular C cells

Question 43

Medullary carcinoma marker

Answer 43

Calcitonin

Question 44

Anaplastic carcinoma 특징

Answer 44

Highly aggressive, poor prognosis

Question 45

Best initial thyroid test

Answer 45

TSH

Question 46

Primary hyperthyroidism labs

Answer 46

Low TSH, high T3/T4

Question 47

Primary hypothyroidism labs

Answer 47

High TSH, low T4

Question 48

Secondary hypothyroidism labs

Answer 48

Low or normal TSH, low T4

Question 49

Low RAIU hyperthyroidism suggests

Answer 49

Thyroiditis or exogenous hormone

Question 50

Primary hyperparathyroidism most common cause

Answer 50

Single parathyroid adenoma

Question 51

Biochemical triad of primary hyperparathyroidism

Answer 51

High calcium, low phosphate, high PTH

Question 52

Bone pathology in hyperparathyroidism

Answer 52

Osteitis fibrosa cystica

Question 53

Mechanism of bone disease in hyperparathyroidism

Answer 53

PTH increases RANKL → osteoclast activation

Question 54

Familial hypocalciuric hypercalcemia feature

Answer 54

Low urine calcium

Question 55

Most common cause of hypocalcemia

Answer 55

Hypoparathyroidism

Question 56

Chvostek sign indicates

Answer 56

Hypocalcemia

Question 57

Trousseau sign mechanism

Answer 57

Neuromuscular excitability from low calcium

Question 58

DiGeorge syndrome defect

Answer 58

22q11 deletion causing absent thymus/parathyroids

Question 59

Pseudohypoparathyroidism 특징

Answer 59

End-organ resistance to PTH with high PTH