Chapter 45: Thyroid Disorders Flashcards

1
Q

Which thyroid hormone is more potent, but has a shorter half-life

A

T3

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2
Q

Free ___ is the unbound, active form that is monitored in patients with thyroid disorders

A

T4

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3
Q

Hypothyroidism = ↓ __ & ↑ __

A

↓ T4 & ↑ TSH

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4
Q

Most common cause of hypothyroidism

A

Hashimoto’s disease (autoimmune)

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5
Q

What is an uncommon, but potentially fatal complication of hypothyroidism

A

Myxedema coma

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6
Q

Initial treatment for myxedema coma

A

IV levothyroxine

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7
Q

What are s/sx of hypothyroidism

A
  • Cold intolerance/sensitivity
  • Dry skin, coarse hair or loss of hair
  • Fatigue; weakness
  • Muscle cramps; myalgia
  • Voice changes
  • Constipation
  • Weight gain
  • Goiter
  • Depression; memory & mental impairment
  • Bradycardia
  • Menorrhagia
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8
Q

Key drugs and conditions that can cause hypothyroidism

A
  • Remember: I TALC*
  • Interferons (also hyperthyroid)
  • TKIs (e.g., sunitinib)
  • Amiodarone (also hyperthyroid)
  • Lithium
  • Carbamazepine
  • Conditions: Hashimoto’s Disease
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9
Q

TSH level and symptoms should be monitored every __-__ weeks until levels are normal

A

4-6 weeks

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10
Q

Too high of a thyroid hormone replacement dose in elderly patients can cause what conditions

A

Afib and fractures

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11
Q

What is the drug of choice for hypothyroidism

A

Levothyroxine (T4)

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12
Q

Levothyroxine brand name

A

Synthroid, Levoxyl, Unithroid

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13
Q

Where should you check for therapeutic equivalencies of a generic brand of levothyroxine

A

Orange book

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14
Q

Full replacement dose of levothyroxine is ___ mcg/mg/day (IBW)

A

1.6

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15
Q

If known CAD, start with __-__ mcg daily of levothyroxine

A

12.5-25

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16
Q

Thyroid, desiccated (T3 & T4) brand name

A

Armour Thyroid

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17
Q

Liothyronine (T3) brand name

A

Cytomel

18
Q

Levothyroxine PO should be taken with ___ at the same time each day for consistent absorption, at least __ min before breakfast or at ____

A

water
60 min
bedtime (at least 3 hours after the last meal)

19
Q

Levothyroxine IV to PO ratio

A

0.75:1

20
Q

Levothyroxine tablet colors

A
  • Remember: Orangutans Will Vomit On You Right Before They Become Large Proud Giants*
  • 25 mcg = orange
  • 50 mcg = white (no dye)
  • 75 mcg = violet
  • 88 mcg = olive
  • 100 mcg = yellow
  • 112 mcg = rose
  • 125 mcg = brown
  • 137 mcg = turquoise
  • 150 mcg = blue
  • 175 mcg = lilac
  • 200 mcg = pink
  • 300 mcg = green
21
Q

Which drugs can ↓ levothyroxine absorption

A

-Antacids and polyvalent cations containing iron, Ca, Al, or Mg multivitamins, cholestyramine, sevelamer and sucralfate –> separate doses by 4 hours

22
Q

Hyperthyroidism = ↓ __ & ↑ __

A

↓ TSH & ↑ T4

23
Q

What are the signs and symptoms of hyperthyroidism

A
  • Heat intolerance or increased sweating
  • Weight loss
  • Agitation, nervousness, irritability, anxiety
  • Palpitations and tachycardia
  • Fatigue and muscle weakness
  • Frequent bowel movements or diarrhea
  • Insomnia
  • Tremor
  • Thinning hair
  • Goiter
  • Exophthalmos, diplopia
  • Light or absent menstrual periods
24
Q

Most common cause of hyperthyroidism

A

Graves’ disease (autoimmune)

25
Q

Drug-induced causes of hyperthyroidism

A

Iodine, amiodarone, and interferons

26
Q

Treatment of hyperthyroid involves drugs &

A

destroying part of the gland via radioactive iodine or surgery

27
Q

What can be used for symptom control of hyperthyroidism

A

Beta-blockers

remember you are trying to slow things down

28
Q

How long does it take to control symptoms with anti-thyroid meds in hyperthyroidism

A

1-3 months

29
Q

MOA of thionamides for hyperthyroidism

A

Inhibit synthesis of thyroid hormones (PTU also inhibits peripheral conversion)

30
Q

Which two drugs are used for hyperthyroidism

A

PTU and methimazole

31
Q

PTU boxed warnings

A

Severe liver injury and acute liver failure

32
Q

PTU and methimazole warnings

A

Hepatotoxicity, agranulocytosis, DILE

33
Q

PTU and methimazole SE

A

GI upset

34
Q

Which drug is preferred in thyroid storm

A

PTU

35
Q

Which trimesters can methimazole be used in

A

2nd and 3rd (has less risk of liver toxicity)

36
Q

PTU is preferred in which trimester

A

1st

37
Q

What is the role of potassium iodide after exposure to radiation

A

it blocks the accumulation of radioactive iodine in the thyroid gland, thus preventing thyroid cancer

38
Q

S/sx of thyroid storm

A
  • Fever (> 103F)
  • Tachycardia, tachypnea
  • Dehydration
  • Profuse sweating
  • Agitation
  • Delirium
  • Psychosis
  • Coma
39
Q

Drug treatment for thyroid storm

A

PTU + SSKI or Lugol’s Solution + Propranolol + Dexamethasone + Aggressive cooling with APAP and cooling blankets

40
Q

What is the safest and preferred treatment for hypothyroidism in pregnancy

A

Levothyroxine

41
Q

Pregnant women treated with thyroid hormone replacement will require __-__% (increase or decrease) in the dose

A

30-50% increase