Endocrine Conditions: Thyroid Disorders

Question 1

Two thyroid hormones produced by the thyroid gland are

Answer 1

T3 and T4

T3 formed from breakdown of T4
T3 = more potent than T4 but shorter half life

Question 2

Thyroid hormone production regulated by….

Answer 2

TSH

Thyroid stimulating hormone (TSH)

Question 3

Which Thyroid hormone is monitored in patients with thyroid disorders

Answer 3

Free T4 (FT4), unbound active form

Question 4

Hypothyroidism is….

Answer 4

deficiency in T4 and elevation in TSH
more commonly in females (~80%)

Question 5

Most common cause of Hypothyroidism is…..

Answer 5

Hashimoto’s disease, autoimmune condition where patients own antibodies attack the thyroid gland

Question 6

Myxedema coma

Answer 6

uncommon but potentially fatal complication of hypothyroidism

treatment = IV Levothyroxine

Question 7

Hypothyroidism lab results

Answer 7

Low free T4 = normal range 0.9 - 2.3 ng/dL
High TSH = normal range 0.3 - 3 mIU/L

Question 8

How to monitor thyroid function in those receiving thyroid hormone replacement with drug txm

Answer 8

TSH every 4-6 weeks until normal then 4-6 months, then yearly

Question 9

Drug of choice for Hypothyroidism is….

Answer 9

Levothyroxine = T4

Question 10

Levothyroxine starting full replacement dose

Answer 10

1.6mcg/kg/day (IBW), titrate from there

Question 11

Armour Thyroid is mix of…

Answer 11

T3 and T4 in variable amountsA

Question 12

Armour Thyroid starting dose

Answer 12

15-30mg QD (15mg in cardiac disease) and titrate by 15mg.

usual doses 60-120mg

Question 13

Levothyroxine PO notes

Answer 13

take with water at same time each day, at least 60min before breakfast or at bedtime 3hrs after last meal

Question 14

Levothyroxine IV to PO conversion

Answer 14

0.75 to 1

Question 15

Hypothyroidism txm

Answer 15

LEvothyroxine = T4
Thyroid Desiccated = T3 & T4
Liothyronine = T3

Question 16

Hypothyroidism txm warnings

Answer 16

decrease dose in cardiovascular disease

Question 17

Orangutans will vomit on you right before they become large proud giants

Answer 17

orange = 25
white = 50
violet = 75
olive = 88
yellow = 100
rose = 112
brown = 125
turquoise = 137
blue = 150
lilac = 175
pink = 200
green = 300

Question 18

Drugs that decrease levothyroxine absorption

Answer 18

antacid and polyvalent cations containing iron, calcium, aluminum, mag, multivitamin, sevelamer and sucralfate = separate doses by 4 hrs

estrogen, SSRI, beta blockers, bunch more. top part most important

Question 19

In hyperthyroidism, then FT4 is ____ and TSH is ____

Answer 19

FT4 is high
TSH is low

Question 20

Most common cause of hyperthyroidism is….

Answer 20

Graves Disease
most common in females ages 30-50
autoimmune disease that stimulate Thyroid to produce too much T4

Question 21

Drug induced causes of hyperthyroidism

Answer 21

iodine
amiodarone
interferons

Question 22

Treating hyperthyroidism with antithyroid medications

Answer 22

take 1-3 months of high doses to control symptoms, once controlled dose should be reduced to prevent hypothyroidism

Question 23

Propylthiouracil (PTU) mechanism of action

Answer 23

inhibits peripheral conversion of T4 to T3

Question 24

Boxed warning for PTU

Answer 24

severe liver injury and acute liver failure
preferred in 1st trimester

Question 25

Methimazole notes

Answer 25

drug of choice overall except in thyroid storm and preferred in 2nd/3rd trimester

Question 26

Methimazole & PTU side effects

Answer 26

GI side effects
headache
rash
fever
constipation

Question 27

When is iodine used?

Answer 27

usually in prep for thyroidectomy

it temporarily inhibits secretion of thyroid hormones but isn’t permanent

Question 28

What blocks accumulation of radioactive iodine in thyroid gland and prevents thyroid cancer?

Answer 28

Potassium iodide

Question 29

Thyroid storm

Answer 29

life threatening medical emergency characterized by decompensated hyperthyroidism

Question 30

Signs and Symptoms of Thyroid storm

Answer 30

Fever > 103
Tachycardia
Tachypnea
Dehydration
Profuse sweating
Agitation
Delirium
Psychosis
Coma

Question 31

Thyroid Storm treatment

Answer 31

PTU preferred (Loading dose 500-100mg + 250mg Q4h)
+
inorganic iodide therapy (SSKI = 5 drops in liquid) Q6h or Luqols solution = 4-8 drops Q6-8hr)
+
beta blocker (propranolol 40-80mg Q6h)
+
systemic steroid (dex 2-4mg Q6h)
+
aggressive cooling with APAP/ cooling blankets/other supportive treatments

Question 32

Pregnancy and Hypothyroidism

Answer 32

Levo is preferred
will have to inc dose by 30-60% during pregnancy likely

Question 33

Pregnancy and Hyperthyroidism

Answer 33

PTU = 1st trimester
Methimazole = 2nd and 3rd trimester