ENDO-Thyroid

Question 1

What is the chief metabolic gland and function?

Answer 1

The thyroid-Synthesis and storage of tetraiodothyronine (T4, thyroxine) and triiodothyronine (T3)

Question 2

Describe the amount of Thyroxine (T4) in the blood

Answer 2

90% of the hormone secreted from the thyroid

Question 3

Describe the converision of the Thyroxine (T4)

Answer 3

converted into T3 in the peripheral tissues.

Question 4

Describe the function of T3

Answer 4

major metabolically active form of thyroid hormone

Question 5

What is the function of thyroid hormone at its target issue

Answer 5

maintain energy homeostasis and regulate metabolism

Question 6

Describe the Hypothalamic-Pituitary-Thyroid Axis

Answer 6

Hypothalmus__TRH__Pituitary__TSH__Thyroid__T3 T4

Question 7

What is essential for the synthesis of thryoid hormone

Answer 7

iodine obtained from our diet

Question 8

Describe the transport of thyroid hormone

Answer 8

T4 and T3 : tightly but reversibly bound to plasma proteins, 70% to TBG- thyroid binding globulin

Question 9

What is one reason that accounts for thyroid disease

Answer 9

Variations in TBG

Question 10

What does the plasma concentration of free T4 and free T3 reflect

Answer 10

the amount of hormone actively exerting an effect on tissues

Question 11

What does the clinical status of thyroid disease correlate with?

Answer 11

<p>correlates with free T4 (FT4) level, NOT total hormone in plasma (TT4)</p>

Question 12

what can increase TBG

Answer 12

1] estrogens: exogenous or pregnancy, 2] hypothyroidism, 3] acute hepatitis, 4] cirrhosis

Question 13

what can decrease TBG

Answer 13

1] androgens, 
2] cirrhosis, 
3] menopause, 
4] glucocorticoids, 
5] nephrotic syndrome, 
6] chronic illness, 
7] Cushing’s syndrome

Question 14

Why is important to know the amount of TBG

Answer 14

Increases in TBG requires a higher dose of thyroxine and vice versa

Question 15

List the Thyroid Function Tests

Answer 15

1] TSH, 2] Free T4

Question 16

What is the normal reference range for TSH

Answer 16

0.4-4.0 mIU/L

Question 17

Describe what the results of TSH indicates

Answer 17

elevated in hypothyroidism ; decreased in hyperthyroidism

Question 18

What is the gold standard for thyroid dysfunction

Answer 18

TSH alone

Question 19

Describe the Free T4 test

Answer 19

direct measurement of unbound thyroxine

Question 20

What is the normal reference range for Free T4

Answer 20

normal= 0.8-1.8 nanograms/dL

Question 21

Describe what the results of Free T4 indicates

Answer 21

decreased/low normal in hypothyroidism; elevated in hyperthyroidism

Question 22

List the additional diagnostic tests for thyroid disease

Answer 22

1] T3, 2] Thyroid antibodies, 3] ESR, 4] Thyroid Scintiscan, 5] Reverse T3, T3 uptake, FTI

Question 23

What test serum level in the diagnosis of autoimmune hyperthyroidism

Answer 23

FREE T3 test

Question 24

What test is useful for autoimmune thyroid disease?

Answer 24

Thyroid antibodies test: TPOAb, TgAb, TSI, TRAb, TBII

Question 25

What is used for evaluation of subacute thyroiditis

Answer 25

Erythrocyte sedimentation rate

Question 26

IS Thyroid Scintiscan used?

Answer 26

thyroid uptake & scan Diagnostically useful, but not ordered first line now because easier to check labs first

Question 27

What tests are not useful in diagnosis of thyroid disease

Answer 27

Reverse T3, T3 uptake, FTI

Question 28

Pt Jane has a high serum TSH? What is the diagnosis

Answer 28

1] Low/low normal FREE T4 = Primary hypothyroidism, 2] High free T4 = Secondary hyperthyroidism (pituitary) (rare)

Question 29

Pt Kathy has a low serum TSH? What could this mean

Answer 29

1] Low free T4 = Secondary hypothyroidism (pit) (rare);

2] High free T4 = Primary hyperthyroidism

Question 30

Describe thyroid uptake and scan

Answer 30

1] Increased uptake with hyperthyroidism;

2] Decreased uptake with hypothyroidism