Lecture 10 - Thyroid Disorders

Question 1

T4 vs T3

Answer 1

T4&raquo_space;» T3 secretion
T3&raquo_space;> T4 activity

Question 2

Hypothyroidism

Answer 2

Low T4/T3 and TRH/TSH high

Question 3

Hyperthyroidism

Answer 3

High T4/T3 and TSH/TRH low

Question 4

Hashimoto’s Disease

Answer 4

Autoimmune

auto-antibodies target thyroid peroxidsease, thyroglobulin, and other thyroid cell antigens

primary cause

Question 5

Iatrogenic cause (caused by us)

Answer 5

usually secondary to management of hyperthyroidism

meds such as…lithium, amiodarone,etc

Question 6

Secondary hypothyroidism

Answer 6

usually pituitary disease

Question 7

Risk factors for Hypothyroidism

Answer 7

Female
Postpartum women
pts with head/neck thyroid irradiation or surgery
Primary pulmonary hypertension
Down’s/Turner’s syndrome
FH autoimmune thyroid disorders
Other Autoimmune disorders

Question 8

Clinical presentation of Hypothyroidism

Answer 8

weak
slow reflexes
coarse skin and hair
cold or dry skin
bradycardia
slow speech, hoarse voice

Question 9

Primary hypothyroidism TSH

Answer 9

> 4.5

Question 10

Secondary hypothyroidism TSH

Answer 10

maybe within or below reference range

Question 11

Treatment options hypothyroidism

Answer 11

T4 = Levo
T3 = liotrix
Combo = liothyronine

T4 (Levo) usually the answer

Question 12

Levothyroxine info

Answer 12

Pro: Drug of choice, cheap, QD,stable
Cons: Drug/Food interaction impact absorption = empty stomach
* pick 1 manufacturer n stick with*

Question 13

which thyroid product should be used for patients who want to avoid pork?

Answer 13

Thyroid USP = armor thyroid, nature-etc

more likely for SE

Question 14

Liothyronine info

Answer 14

pro: rapid onset, uniform absorption

cons: TID, $$$, higher CV effects, hard to monitor

Question 15

Starting dose Levothyroxine

Answer 15

normal: 1.6mcg/kg IBW

Hx CVD = 25mcg QD
Longstanding disease/elderly = 50mcg QD

Question 16

adjusting dose levothyroxine

Answer 16

Titrate by 12.5-25 mcg/day if pts still hypothyroid

Question 17

Long-term maintenance levothyroxine

Answer 17

Stick with 1 product manufacturer

Recheck in 3 months, then every 6-12 months

Question 18

Special pop, recheck TSH 4-6wk after adjustment

Answer 18

Preg, inc req in 75% of women
Elderly, dec dose req
Weight loss, may need dec dose req

Question 19

Goal TSH?

Answer 19

0.5-4.5 for exam purposes

Question 20

Levothyroxine SE

Answer 20

Allergic reactions
reduced BMD and inc risk of fracture

excessive doses = HF, angina pectoris, MI

Question 21

DDI Levothyroxine

Answer 21

stuff affecting stomach and GI absorption

give before food/meds

Question 22

Levothyroxine CI

Answer 22

Hypersensitivity
thyrotoxicosis

Question 23

Levothyroxine pt education

Answer 23

several weeks for symptoms to improve
Take empty stomach
Take 4h apart from antacids, iron, calcium supp
pick 1 brand n stick with it

Question 24

Subclinical hypothyroidism definition

Answer 24

Elevated TSH (above upper ref range) with normal T4

Question 25

Should you initiate hypothyroidism treatment?

Answer 25

TSH > 10 = probs sart levo 25 TSH < 10 = consider based on individual factors

Question 26

Myxedema Coma Treatment

Answer 26

Levo IV 300-500 bolus, 75-100 IV maintenance until stable and start PO Hydrocortisone 100mg Q8H IV until adrenal suppression ruled out Supportive care

Question 27

Myxedema Coma Symptoms

Answer 27

Hypothermia Hypoventilation Advanced stages of hypothyroid symptoms delirium, coma

Question 28

Grave's Disease

Answer 28

autoimmune disorder with thyroid stimulating antibody acting on thyroid Primary

Question 29

Hyperthyroidism risk factors

Answer 29

Female FH of autoimmune conditions FH of hyperthyroidism Pregnancy, some viral infections Age = young n old, not so much middle

Question 30

Hyperthyroidism clinical presentation

Answer 30

Tachycardia heat intolerance diarrhea warm, smooth moist skin fine hair gynecomastia ***Exophalmos & retraction of eyelids *** Grave's Disease

Question 31

Hyperthyroidism treatment options

Answer 31

Reduce thyroid hormone: Antithyroid drugs Radioactive iodine Surgery Adjunctive options: Symptomatic control ie BB, clonidine, Non-DHP CCBs

Question 32

Antithyroid Drugs

Answer 32

Methimazole = generally preferred Propylthiouricil (PTU) = pref in preg 1st trimester, thyroid storms Onset: 4-6 wk response, 4-6month max response, 1-2 txm last

Question 33

Who should use ATD?

Answer 33

> 40yrs old low T4/T3 ratio ( < 20) Small goiter < 50g short duration disease < 6 month no prev hx of relapse therapy > 1-2yrs duration low TSAb titers at BL consider use pre-op prep 6-8wk before thyroidectomy

Question 34

Patient education ATD

Answer 34

Side effects Tell doc about rash, jaundice, acolic stool or dark urine, arthralgia, ab pain, nausea, fatigue, fever, pharyngitis

Question 35

Who are ATD 1st line treatment for

Answer 35

preg, children, adolescents

Question 36

Radioactive Iodine therapy info

Answer 36

consider in: "Hot nodules", Toxic MNGs, Graves Disease onset : weeks to see destruction Kills gland tissue essentially pretreat with ATD to prevent thyroid storm

Question 37

When should iodine be stated after RAI?

Answer 37

3-7 days after to prevent interference of uptake of RAI in thyroid gland

Question 38

RAI ADE & CI

Answer 38

CI = pregnancy Short term ADE: Mild thyroidal tenderness, dysphagia Long term ADE: Hypothyroidism

Question 39

RAI Pros and Cons

Answer 39

Pro: cure hyperthyroidism Outpatient therapy lowest cost adjust QOL best for toxic nodules and multi nodular goiter Con: perm hypothyroidism in >60% pts can worsen ophthalmopathy preg deferred 6-12mnth no breastfeeding

Question 40

Surgery thyroid

Answer 40

Consider pts with large gland >80g, severe ophthalmopathy, and lack of remission on Anti thyroid drug adj therapy: pre-treat methimazole 6-8wk, iodides 10-14 day before surgery and propranolol severe weeks preop, and 7-10 days post op

Question 41

Surgery pro and cons

Answer 41

Pro: rapid, effective thyroid cancer and nodules Con: permanent, invasive, scars

Question 42

Iodides info

Answer 42

used as adj therapy ADE: iodize = metallic taste, burning mouth and throat, salivary gland swelling CI: Toxic MNG DI: start 3-7 days after RAI

Question 43

Who gets Treated for Subclinical Hyperthyroidism

Answer 43

TSH < 0.1 if age >65, or > 65 w/ Heart Disease, Osteoporosis, menopausal (not on estrogens or bisphos), hyperthyroid symptoms If TSH 0.1-0.4 then consider treating If < 65 n asymptomatic TSH < 0.1 then consider treating, 0.1-0.4 then observe

Question 44

Thyroid storm

Answer 44

medical emergency, mortality ~ 20% symptoms: > 103F, Tachycardia, tachypnea, dehydration, delirium, coma, nausea, vomiting, diarrhea. lasts about 72hrs, up to 8 days