Thyroid

Question 1

What are the two main cell types of the thyroid gland?

Answer 1

Follicular and parafollicular

Question 2

What is the role of parafollicular cells?

Answer 2

Secretes calcitonin

Question 3

How do thyroid hormones affect protein synthesis?

Answer 3

Stimulation of protein synthesis

Question 4

How do thyroid hormones affect carbohydrates and lipids?

Answer 4

Increases carbohydrate and lipid catabolism

Question 5

How do thyroid hormones affect the CNS?

Answer 5

They play a critical role in the development of the brain in fetuses and neonates

Question 6

Differentiate hyperthyroidism from thyrotoxicosis

Answer 6

Thyrotoxicosis- elevated T4/T3 in the body (endogenous or exogenous, or struma ovarii)

Hyperthyroidism- hyperfunctioning of the thyroid gland

Question 7

Describe the CNS/neuromuscular symptoms of hyperthyroidism

Answer 7

nervousness, emotional lability, insomnia, muscle weakness, fine tremor of the hands

Question 8

What are the ocular symptoms of hyperthyroidism?

Answer 8

wide staring gaze and lid lag

Question 9

What is the single more sensitive screening test for hyperthyroidism?

Answer 9

TSH measurement

Low in hyperthyroidism

Question 10

Following a radioactive iodine uptake administration, what would the uptake pattern be in Graves disease, toxic adenoma, and thyroiditis?

Answer 10

Graves- diffuse uptake
Toxic adenoma- localized
Thyroiditis- reduced uptake

Question 11

What is the most common cause of hypothyroidism in developing countries? In developed countries?

Answer 11

Developing countries: iodine deficiency

Developed countries: Hashimoto’s thyroiditis

Question 12

What is the secondary cause of hypothyroidism?

Answer 12

Pituitary failure

Question 13

What is hypothyroidism of children called? Adults?

Answer 13

Infants/early childhood- cretinism

Adults- myxedema

Question 14

What are the sequelae of cretinism?

Answer 14

Depends on when the iodine deficiency occurred- if mom is also iodine deficient, it is worse

Mental retardation, short stature, coarse facial features

Question 15

What are the characteristics of myxedema?

Answer 15

Gradual slowing of mental/physical function

Fatigue, lethargy, apathy, slowed speech…

Question 16

What is the most sensitive screening test for hypothyroidism?

Answer 16

TSH levels (they will be increased)

Question 17

Name two types of thyroiditis with pain

Answer 17

Infectious- usually bacterial, you don’t intervene

Subacute granulomatous De Quervain’s thyroiditis

Question 18

List three types of painless thyroiditis

Answer 18

Subacute lymphocytic thyroiditis
Reidel’s thyroiditis
Hashimoto’s thyroiditis

Question 19

What is the cause of Hashimoto’s thyroiditis?

Answer 19

Autoimmune destruction of thyroid gland –> failure and hypothyroidism

Question 20

What are the three immunologic attacks against the thyroid?

Answer 20

CD8+ cytotoxic T cells
IFN-gamma/pro-inflammatory cytokine destruction
Anti-thyroid antibodies

Question 21

What are the three autoimmune antibodies seen in Hashimotos?

Answer 21

TPO
TSH receptor
Iodine receptor

Question 22

What is the characteristic cell seen in Hashimoto’s thyroiditis?

Answer 22

Hurthle cells/ oncocytes - loaded with mitochondria and therefore appear granular/very pink

Question 23

People with Hashimoto’s are at increased risk of developing what neoplasm?

Answer 23

Non-Hodgkins B cell lymphoma

Question 24

What is the etiology of De Quervain’s thyroiditis?

Answer 24

Viral or Post-viral inflammatory response-

Either viral antigens or infection induced T-cell activation leads to destruction of thyroid cells

Question 25

What is the prognosis of De Quervain's thyroiditis?

Answer 25

Self-limited

Question 26

Is De Quervain's thyroiditis painful or painless?

Answer 26

Painful

Question 27

What is the clinical course of De Quervain's thyroiditis?

Answer 27

History of upper respiratory infection Transient hyperthyroidism diminishing in 2-6 weeks Recovery to normal function in 6-8 weeks

Question 28

What are the symptoms of Riedel's thyroiditis?

Answer 28

Extensive fibrosis involving thyroid and contiguous neck structures (goes OUTSIDE the thyroid and squeezes those structures) Hard and fixed masses mimic cancer

Question 29

What is the most common cause of endogenous hyperthyroidism?

Answer 29

Graves disease

Question 30

What is the triad of findings associated with Graves?

Answer 30

1. Diffuse hyperfunctional enlargement of the thyroid 2. Infiltrative ophthalmopathy --> exophthalmos 3. Infiltrative dermopathy - pretibial myxedema

Question 31

What is the most common autoantibody seen in Graves disease?

Answer 31

Thyroid stimulating immunoglobulin (TSI) -Bind the TSH receptor and mimics its action

Question 32

What differentiates the histology of papillary carcinoma of the thyroid from graves?

Answer 32

Graves: papillary structures with NO fibrovascular core, pale colloid with SCALLOPED margins

Question 33

What is a toxic vs nontoxic goiter?

Answer 33

Toxic: hyperfunctioning | Non-toxic: not hyperfunctioning

Question 34

What is the progression of a diffuse goiter?

Answer 34

They all become multinodular goiters

Question 35

Are the multinodular goiter thyroids usually hypothyroid, euthyroid or hyperthyroid

Answer 35

Euthyroid

Question 36

What is Plummer's Syndrome?

Answer 36

Toxic multinodular goiter due to development of an autonomous nodule

Question 37

What is the most common thyroid cancer?

Answer 37

Papillary thyroid carcinoma

Question 38

Are nodules in young patients more likely to be benign or malignant?

Answer 38

Malignant

Question 39

What is the only benign tumor of the thyroid?

Answer 39

Follicular Adenoma

Question 40

What are two genes seen in both follicular adenomas and follicular carcinomas?

Answer 40

RAS and PAX-PPARgamma fusion gene

Question 41

How do we differentiate follicular adenomas from follicular adenocarcinomas?

Answer 41

Follicular adenomas are encompassed by a well-defined capsule (no infiltration)

Question 42

What is the treatment for a follicular adenoma?

Answer 42

Lobectomy These have an excellent prognosis- no recurrence

Question 43

What is medullary carcinoma of the thyroid?

Answer 43

Neuroendocrine carcinoma of the parafollicular (C) cells

Question 44

What are the histologic features of papillary carcinoma of the thyroid?

Answer 44

Branching papillae with a fibrovascular core lined with multiple layers of cuboidal to columnar epithelium + Orphan annie-eyed nuclei and psammoma bodies

Question 45

Which variant of papillary carcinoma has a poor prognosis?

Answer 45

Tall cell variant

Question 46

Papillary carcinomas with which genetic marker correlates to a worse prognosis?

Answer 46

BRAF

Question 47

What is the most common genetic rearrangement seen in papillary thyroid canceR?

Answer 47

RET/PTC

Question 48

Follicular carcinoma of the thyroid must be separated into what type subsets, as their prognosis is very different.

Answer 48

Minimally invasive- great prognosis | Widely invasive- bad prognosis

Question 49

Which two hormones may be secreted in medullary carcinoma of the thyroid?

Answer 49

ACTH or calcitonin

Question 50

Medullary carcinoma of the thyroid is associated with which MEN syndrome?

Answer 50

MEN2A or MEN2B

Question 51

Amyloid deposition is seen in which thyroid carcinoma?

Answer 51

Medullary carcinoma

Question 52

Which thyroid cancer has the worst prognosis?

Answer 52

Anaplastic carcinoma- 100% death within a year

Question 53

What is a thyroglossal duct cyst and what's the problem with it?

Answer 53

Incomplete atrophy of the thyroglossal duct cyst- presents at any age as a midline cyst or anterior mass Risk of infection/abscess