Thyroid

Question 1

What does the thyroid make more of, T3 or T4?

Answer 1

T4

Question 2

How is T3 & T4 transported?

Answer 2

Protein bound & freely

Question 3

Does the protein bound hormone exhibit biologic effects?

Answer 3

No, only the free hormone

Question 4

What is the role of thyroid hormone, especially at birth?

Answer 4

Crucial for cell differentiation – if absent at birth can cause severe mental retardation = “creatinism”

Question 5

What is the role of thyroid hormone as an adult?

Answer 5

Helps maintain thermogenic and metabolic homeostasis in the adult. Also essential for normal metabolism, protein synthesis and organ function

Question 6

How much iodine do we need on a daily basis?

Answer 6

0.2mg

Question 7

Most commonly, thyroid disorders are what type of disorder?

Answer 7

Autoimmune process

Question 8

What type of history questions should you ask someone who you suspect has a thyroid disorder?

Answer 8

visual changes, skin/hair, mood changes, energy level, palpitations, constipation/diarrhea, weight changes, fluid retention, heat/cold intolerance.

Question 9

What must you always check on PE in someone you suspect with a thyroid disorder?

Answer 9

visual/eyes, weight, scalp/hair, neck, skin, heart, abdomen, extremities, reflexes and thyroid exam neuro

Question 10

What are the most informative test for thyroid function?

Answer 10

Thyroid stimulating hormone (TSH) and free T4, sometimes free T3

Question 11

Which test is an extremely sensitive indicator for thyroid function?

Answer 11

TSH – almost always abnormal with hyper/hypothyroid states

Question 12

What controls the secretion of TSH?

Answer 12

Negative feedback from thyroid hormones

Question 13

What’s the normal range for TSH?

Answer 13

0.27-4.2

Question 14

If TSH is low, what does that usually indicate?

Answer 14

Primary hyperthyroidism

Question 15

If TSH is high, what does that usually indicate?

Answer 15

Hypothyroidism

Question 16

If the TSH is normal does it always rule-out hypo/hyperthyroidism?

Answer 16

No - on very rare exceptions

Question 17

What if a patient’s TSH is in the 3-6 range?

Answer 17

Should follow for the development of hypothyroidism

Question 18

What’s the goal TSH level is someone with hypothyroidism?

Question 19

So, in what type of patients should we always check TSH levels?

Answer 19

Prenatal, mood disorder, Afib, weight changes, dementia/delirium, and dyslipidemia

Question 20

If TSH, is such a good test, why would we check T4?

Answer 20

Occasionally needed to confirm hypo/hyperthyroidism, and useful in management of thyrotoxicosis

Question 21

What’s the normal ranges of Free T4?

Answer 21

9-24

Question 22

When would we check a T3?

Answer 22

If TSH is low, but Free T4 is normal and patient presents clinically with hyperthyroid → check T3 (total & free)

Question 23

You said, that many thyroid diseases are autoimmune based… so then what tests would you do to confirm autoimmune thyroid disease?

Answer 23

Anti-thyroid antibodies

Question 24

When would the anti-thyroid antibodies be elevated?

Answer 24

Hashimoto’s thyroiditis and Graves disease

Question 25

What do TSH-receptor antibodies detect, what is it also known as, and what does it do?

Answer 25

Detects – IgG AKA – TSI (thyroid stimulating immunoglobulin) It stimulates hormone production and is elevated in Graves disease

Question 26

If a patient presents with increasing fatigue, weight gain, with dry skin, and losing hair, what diagnosis do you think?

Answer 26

Hypothyroidism

Question 27

What is hypothyroidism?

Answer 27

Autoimmune, AKA Hashimoto’s Thyroiditis

Question 28

What causes Hypothyroidism?

Answer 28

Idiopathic, can occur post radioactive iodine, congenital (screen newborns), or drug induced Lymphocytic infiltration of the gland – early phase may be hyperthyroidism (from stored hormone) but end results is hypothyroidism

Question 29

What are some early symptoms of hypothyroidism?

Answer 29

Fatigue, lethargy, weakness, cold intolerance, constipation, dry skin, hair loss, HA, and menorrhagia

Question 30

What are some late symptoms of hypothyroidism?

Answer 30

Slow speech, muscle cramps, hoarse voice, weight gain, amenorrhea

Question 31

What are some PE findings of early hypothyroidism?

Answer 31

Thin, brittle nails; thin, dry hair; delayed deep tendon reflex

Question 32

What are some PE findings of late hypothyroidism?

Answer 32

Goiter, facial/eyelid puffiness, alopecia, bradycardia, edema (non-pitting!), pleural/pericardial effusions

Question 33

If the PE finding shows abnormal interstitial accumulation in skin giving it a waxy/coarsened appearance – what is this known as?

Answer 33

Myxedema

Question 34

What might you see on labs with hypothyroidism?

Answer 34

Increased TSH, decreased FT4, elevated triglycerides, low HDL, anti-thyroid antibodies

Question 35

What would be a late lab finding of Hypothyroidism?

Answer 35

Anemia & Elevated LFT’s

Question 36

How do you treat hypothyroidism?

Answer 36

Levothyroxine – Initiate 50-100ug/day and titrate towards full dose over time

Question 37

What must we do when we start a patient on Levothyroxine treatment?

Answer 37

Follow their TSH levels – every 2-3 months, until normal (0.5-2.5)

Question 38

What is our goal when treating a patient with hypothyroidism?

Answer 38

Symptoms improve slowly (months)

Question 39

Will the lipids improve with levothyroxine in a patient with hypothyroidism?

Answer 39

They will improve a little but lipid meds usually needed

Question 40

How do we prevent and treat congenital hypothyroidism?

Answer 40

Early detection! Replacement therapy (10-15)

Question 41

If a patient presents with unexplained weight loss, fatigue, who often feels hot and anxious – what diagnosis are you thinking?

Answer 41

Hyperthyroidism

Question 42

What else is hyperthyroidism known as?

Answer 42

Thyrotoxicosis

Question 43

What is the most common etiology of hyperthyroidism?

Answer 43

Graves disease

Question 44

What are other etiologies for hyperthyroidism?

Answer 44

Toxic (“hot”) adenomas, early phase hasimoto’s (from stored hormone), factitious (excessive thyroid hormone intake), TSH adenoma, or amiodarone

Question 45

What is Graves disease?

Answer 45

Autoimmune disease, caused by TSH-receptor antibody (IgG) causes hypersecretion, hypertrophy, and hyperplasia of the thyroid (goiter)

Question 46

What are some of the symptoms associated with hyperthyroidism?

Answer 46

Hyperactivity, irritability, heat intolerance, sweating, palpitations, fatigue, weakness, increased appetite, weight loss, diarrhea, oligomenorrhea

Question 47

What might you find on PE with hyperthyroidism?

Answer 47

Tachycardia, arrhythmias, fine tremor, goiter/bruit, oily fine hair, proximal muscle weakness, opthalmopathy, dermopathy, and hyperreflexia

Question 48

What would the labs show with hyperthyroidism?

Answer 48

Very low TSH (often

Question 49

What type of hyperthyroidism that occurs in 2-5% of patients do we need to remember?

Answer 49

T3 thyrotoxicosis

Question 50

What 2 signs & symptoms are unique to Graves disease?

Answer 50

Opthalmopathy – Proptosis with lid-lag, conjunctival inflammation and corneal drying Dermopathy – pre-tibial areas leading to edema, thickened skin (pre-tibial myxedema)

Question 51

What are some complications of Graves disease?

Answer 51

Cardiac arrhythmias – Afib! Thyroid storm

Question 52

How can we treat Graves disease?

Answer 52

MUST have an endocrinologist consult Propranolol (heart) Thiourea drugs = Propylthiouricil (PTU) or Methimazole – inhibits thyroid peroxidase and block organification of iodine.

Question 53

What are some of the side effects of Thiourea drugs?

Answer 53

Agranulocytosis and pruritis. Must follow WBC & Free T4 Must monitor for liver injury! Cannot use in 1st tri of pregnancy (due to birth defects)

Question 54

If a patient with Graves disease stops returns to normal levels and then stops treatment, what can occur?

Answer 54

Recurrent thyrotoxicosis in 50%

Question 55

What is the definitive treatment of choice for Grave’s disease in the US?

Answer 55

Radioactive iodine (131I) – destroy overactive thyroid tissue

Question 56

What must we monitor when giving RAI for grave’s disease? Why?

Answer 56

Follow free T4. Permanent hypothyroidism often develops within one year, thus thyroid replacement therapy needed for life. Can’t use in pregnancy!

Question 57

What may worsen after giving RAI for grave’s disease?

Answer 57

Opthalmopathy; especially in smokers

Question 58

When would thyroid surgery be indicated?

Answer 58

Graves in children or hyperthyroidism during pregnancy that can’t be control with thiourea drugs. For patients with Grave’s that have failed 131I

Question 59

What must you do if you notice a nodule on a patient’s thyroid?

Answer 59

Must do a fine needle aspiration to R/O cancer

Question 60

A thyroid nodule may be benign, but what can it cause?

Answer 60

Thyrotoxicosis (Toxic thyroid nodule)

Question 61

How do you treat a toxic thyroid nodule?

Answer 61

RAI if >40 Surgery or RAI if

Question 62

If a fine needle aspiration is done on a nodule and thyroid cancer is determined, what type of thyroid dysfunction would they have?

Answer 62

None!

Question 63

What does thyroid cancer feel like?

Answer 63

A firm, non-tender nodule

Question 64

How do you treat thyroid cancer?

Answer 64

Near total thyroidectomy, post-op suppress TSH, follow-up with total body RAI