Pathology Ch. 24: The Endocrine System- Thyroid

Front 1

Epithelium that usually lines the thyroid

Back 1

Cuboidal epithelium

Front 2

TSH levels in primary hypothyroidism? secondary?

Back 2

High
Low

Front 3

TSH utilizes what receptor system

Back 3

G protein w/ activation of cAMP

Front 4

Large doses of iodine

Back 4

Inhibit proteolysis of thyroglobulin. Thus, thyroid hormone is synthesized in increasing amounts but is not released into the blood.

Front 5

Thyrotoxicosis

Back 5

Hypermetabolic state caused by elevated levels of free T3 and T4

Front 6

What are the earliest and most consistent features of hyperthyroidism?

Back 6

Cardiac manifestations:
Increased CO due to increased O2 demands from increased metabolic functions and cardiac contractility.

Front 7

Thyrotoxic cardiomyopathy

Back 7

Reversible left ventricular dysfunction and "low output" heart failure

Front 8

True thyroid opthalmopathy is associated with what disease

Back 8

Graves disease

Front 9

Pt presents febrile with tachycardic arrhythmia. What thyroid condition could this be? What is the underlying condition? What causes the acute presentation?

Back 9

Thyroid storm:
Results from acute elevation of catecholamine levels during infection, surgery, cessation of anti-thyroid medications, or stress. The underlying condition is Graves disease.

Front 10

In older pt's, what would chronic hyperthyroidism results in?

Back 10

bone resorption increases, causing porosity of cortical bone and reducing the volume of trabecular bone.This leads to osteoporosis and an increased risk of fractures.

Front 11

Congenital hypothyroidism is most often the result of?

Back 11

Endemic iodine deficiency

Front 12

Mutations in what enzyme are the most common cause of dyshormonogenetic goiter?

Back 12

Thyroid peroxidase

Front 13

Classic clinical manifestations of hypothyroidism

Back 13

Cretinism and myxedema

Front 14

Hypothyroidism that develops in infancy or early childhood with severe mental retardation and growth deficiencies This was usually the result of? During pregnancy, when is cretinism most likely to develop?

Back 14

Cretinism
Iodine deficiency
Before the fetal thyroid has developed

Front 15

Thyroid hormones regulate what proteins that could lead to decreased cardiac output and muscle fatigue with slowed relaxation

Back 15

Calcium ATPases

Front 16

Accumalation of what substances leads to non-pitting edema

Back 16

GAGs and hyaluronic acid

Front 17

Acute infectious thyroiditis may result from spread from what adjacent structure?

Back 17

Fistula from the piriform sinus adjacent to the larynx

Front 18

Most common cause of hypothyroidism in the US

Back 18

Hashimoto thyroiditis

Front 19

In Hashimoto's circulating anti-bodies attack what? What thyroid features become apparent?

Back 19

Thyroglobulin and thyroid peroxidase
Progressive depletion of thyrocytes by apoptosis and replacement of thyroid parenchyma by mononuclear cell infiltration and fibrosis.

Front 20

Histological features of hashimoto's thyroiditis

Back 20

Diffuse enlargement of thyroid gland
Mononuclear inflammatory infiltrate with germinal centers
Hurthle cells: Epithelial cells with abundant eosinophilic cytoplasm that line atrophic follicles.

Front 21

Hurthle cells

Back 21

Metaplastic response to normally low cuboidal follicular epithelium to ongoing injury.

Front 22

Classic hashimoto's has what histological presentation?

Back 22

Increased interstitial connective tissue

Front 23

Hashimoto's with severe follicular atrophy and dense fibrosis with bands of acellular collagen encompassing the residual thyroid tissue?

Back 23

Fibrous variant

Front 24

How does Hashimoto's most often come to clinical attention? What may occur in the early stages of disease

Back 24

Painless enlargement of the thyroid
Hashitoxicosis: Disruption of thyroid follicles causes transient hyperthyroidism with increased T4/T3 and decreased TSH.

Front 25

Long term Hashimoto's disease increases the risk for what?

Back 25

Non-Hodgkin's B-cell lymphoma, especially marginal zone lymphomas of MALT

Front 26

Pt presents with painful swallowing and enlarged thyroid following an acute respiratory infection. Most likely cause? Peak incidence? How is the thyroid damaged? Histological presentation?

Back 26

De Quervain thyroiditis:
Triggered by a viral infection possibly from coxsackie virus, mumps, measles, or adenovirus. The peak incidence is during the summer. The virus leads follicular destruction from cytotoxic T cells.
Histological presentation shows intact capsule with multinucleate giant cells that enclose naked pools of colloid. (Granulomatous inflammation)

Front 27

What histo presentation occurs in later stages of Subacute granulomatous thyroiditis

Back 27

Chronic inflammatory infiltrate and fibrosis replaces the foci of injury.

Front 28

Most common cause of thyroid pain? What is the recovery process?

Back 28

De Quervain's thyroiditis:
Self-limited with complete recovery. Not auto-immune

Front 29

How does subacute lymphocytic thyroiditis come to clinical attention? Is there pn? What is the histological presentation? How is this distinguished from Hashimoto's?

Back 29

Mild hyperthyroidism and goitrous enlargement
There is no pain
Lymphocytic infiltration with hyperplastic germinal centers within the thyroid parenchyma.
Fibrosis and Hurthle cell metaplasia are not prominent features.

Front 30

In this condition almost all pt's become euthyroid

Back 30

Postpartum (lymphocytic) thyroiditis

Front 31

Most common cause of endogenous hyperthyroidism

Back 31

Graves disease

Front 32

Clinical triad of findings in Graves disease

Back 32

Hyperthyroidism, exopthalmopathy, pretibial myxedema

Front 33

Target of antibodies in graves disease. What are these called? How does in cause hyperthyroidism?

Back 33

TSH receptor
Thyroid Stimulating immunoglobulin
IgG's bind to the TSH receptor and mimic the actions of TSH

Front 34

Immunoglobulins implicated in the proliferation of thyroid follicular epithelium

Back 34

Thyroid growth stimulating epithelium

Front 35

What causes Graves opthalmopathy. What does evidence suggest is the target of antibodies?

Back 35

Infiltration of retro-orbital connective tissue with mononuclear cells predominantly T cells, inflammatory edema, and accumulation of GAG's.
Orbital pre-adipocyte fibroblasts that express TSH receptors.