Thyroid Dysfunction

Question 1

Sx of Hyperthyroidism

Answer 1

Nervousness
weight loss
increased appetite
decreased appetite 
Fatigue
Tremor
heat intolerance

Question 2

Sx of Hypothyroidism

Answer 2

Mental slowness
Weight Gain
Increased appetite
Decreased Appetite
Fatigue
Muscle Cramps
Cold Intolerance

Question 3

Etiology of hypothyroidism

Answer 3

Primary:
-Chronic Autoimmune thyroiditis (Hashimoto's)
-Transient: Silent/postpartum thyroiditis
& Subacute/granulomatous thyroiditis
-Thyroid surgery/thyroidectomy
-Radioactive iodine
Central
-Pituitary Tumor`

Question 4

Thyroid Autoantibodies:

Answer 4

TPO (thyroid peroxidase)

Tg (thyroglobulin)

Question 5

What is more common in CO, hypo or hyper?

Answer 5

Hypo

Question 6

Risk of developing hypothyroidism in pts w/ elevated TSH and positive thyroid Abs

Answer 6

rate ~5% per year

Question 7

Normal TSH level

Answer 7

0.4-4.0

Question 8

When to Tx hypo

Answer 8

-TSH >10mU/L
below that is controversial
-Tx with levothryeoxine
Goal: TSH b/t 0.51 to 3.0

Question 9

What is myxedema coma?

Answer 9

An extreme form of hypothyroidism, so severe as to readily progress to death unless diagnosed promptly and treated vigorously -EMERGENCY

Question 10

Nl FT4 level

Answer 10

0.8-1.8ng/dl

Question 11

Type 3 Deiodinase Fxn

Answer 11

Convert T4 to reverse T3

Question 12

Type 1 or 2 Deiodinase Fxn

Answer 12

convert T4 to T3

Question 13

Transport of T4 in blood

Answer 13

99.98% of T4 is bound
TBG (thyroid-binding globulin)
TBPA (thyroid-binding prealbumin)
Albumin

Half life = 7 days

Question 14

Transport of T3 in blood

Answer 14

99.8% of T3 is bound
TBG (thyroid-binding globulin)
Albumin

Half life = 1 day

Question 15

Causes of increased FT3/4

Answer 15

Hyperthyroidism/Thyrotoxicosis

Thyroid hormone resistance

Question 16

Causes of decreased FT3/4

Answer 16

Hypothyroidism
Euthyroid sick syndrome
Drugs

Question 17

The single best test to screen for thyroid dysfunction

Answer 17

TSH

Question 18

TSH in primary hypothyroidism

Answer 18

Elevated

Question 19

TSH in primary hyperthyroidism

Answer 19

Supressed

Question 20

When can one not rely on a TSH?

Answer 20

Abnormal pituitary gland

Question 21

T of F: do you want to order a T3?

Answer 21

Nope, T4 is the way to go

Question 22

Causes o Thyrotoxicosis

Answer 22

• Overproduction of T4/3 (true hyper)

- High release of preformed T3/4 (not true hyper)

Question 23

How do you determine the cause of thyrotoxicosis?

Answer 23

Radioactive iodine(123I) uptake and scan
-A “normal” or elevated iodine uptake in the setting of a low TSH is abnormal and indicates autonomous production of thyroid hormone.

Question 24

Causes of high uptake hyperthyroidism

Answer 24

• Thyrotropin receptor antibody: Graves’ disease

- Thyroid autonomy: Toxic adenoma & Toxic MNG

Question 25

causes of Low Uptake “Hyperthyroidism”

Answer 25

-Subacute thyroiditis: 
Granulomatous thyroiditis (viral)
Lymphocytic thyroiditis (Postpartum thyroiditis)
Amiodarone
Radiation
-Ectopic thyrotoxicosis:
Factitious

Question 26

Tx of Graves

Answer 26

Medications:
-Antithyroid drugs (methimazole, propylthiouracil)
-Beta blockers-
Radioactive Iodine (131I)
Surgery

Question 27

How does thyroid disease affect reproductive function in women?

Answer 27

• High free T4 increases sex hormone binding globulin (SHBG) and this results in a lower free estradiol level that leads to lighter menstrual bleeding and amenorrhea
• Low free T4 decreases SHBG, increases free estradiol and leads to hypermenorrhea.