Thyroid Flashcards
- The serum T4 level is not a good test for screening and monitoring for thyroid disease because:
A. The assay is difficult to perform and not available in most clinical laboratories
B. The results can be affected by alteration in protein binding, making interpretation difficult
C. It is too sensitive, with a high percent of false positive results
D. Serum T3 is a better test since it is the active hormone
E. All of the above
B
- The prevalence of hypothyroidism is higher in:
A. Women
B. Elderly patients
C. Patients with other autoimmune endocrine disorders
D. Patients treated with amiodarone
E. All of the above are correct
A
- What is the target TSH range (mIU/L or μIU/mL) for patients being treated for
hypothyroidism or hyperthyroidism?
A. Undetectable
B. 2.5 to 4.5
C. 1.4 to 2.5
D. 0.5 to 4
E. 4 to 5
D
- Which of the following is a reasonable choice in treating a patient with newly diagnosed hypothyroidism?
A. Desiccated thyroid
B. liotrix
C. levothyroxine
D. liothyronine
E. All are reasonable choices
C
- Levothyroxine products should not be substituted at refill because:
A. No marketed products are AB rated by the FDA Orange Book.
B. All state regulations prohibit the substitution of narrow therapeutic index drugs.
C. Small differences in bioavailability may result in loss of disease control.
D. Patients will be nonadherent if it is switched.
E. A and B are correct.
C
- Patients with mild or subclinical hypothyroidism should be considered for LT4 therapy if the patient has:
A. A family history of thyroid disease
B. Elevated LDL cholesterol
C. Positive TSHR-AbS antibody
D. A history of hypertension
E. All of the above
B
- What is the starting daily dose of LT4 in an 87 kg (191 lb), 5’4” (163 cm) 32-year old patient, otherwise healthy, with overt hypothyroidism?
A. 25 mcg
B. 50 mcg
C. 75 mcg
D. 100 mcg
E. 150 mcg
D
- In a patient receiving stable LT4 therapy, laboratory monitoring should be performed every
A. Month
B. 6 to 8 weeks
C. 3 months
D. Year
E. 5 years
D
- Which of the following is a consequence of undertreatment with LT4?
A. Hypercholesterolemia
B. Cardiovascular disease
C. Fatigue
D. Infertility
E. All of the above
E
- Untreated hyperthyroidism in the elderly can result in:
A. Mania
B. Atrial fibrillation
C. Deafness
D. Hirsutism
E. A and D are true
B
- Which of the following drugs may be used to quickly relieve symptoms seen in
hyperthyroidism?
A. Radioactive iodine
B. Propylthiouracil
C. Methimazole
D. Lithium
E. Propranolol
E
- Why is propylthiouracil (PTU) the antithyroid therapy of choice in pregnant patients with Graves disease?
A. It is less hepatotoxic than methimazole (MMI)
B. It may be less teratogenic than MMI
C. It has less risk of causing fetal hypothyroidism than MMI
D. It causes less agranulocytosis in these patients than MMI
E. A and C are true
B
- In the setting of antithyroid therapy, which of the following statements regarding agranulocytosis is not true?
A. Agranulocytosis occurs in 0.3% of patients.
B. Patients may present with fever and sore throat.
C. Monitoring for agranulocytosis is controversial.
D. Incidence of agranulocytosis is higher in patients treated with propylthiouracil.
E. Agranulocytosis usually occurs within the first 3 months of therapy.
D
- Why has use of methimazole increased dramatically in the United States compared to propylthiouracil (PTU) in the treatment of most patients with Graves disease?
A. It may cause fewer adverse effects such as hepatotoxicity than PTU.
B. It has a shorter half-life than PTU.
C. It is renally excreted so no adjustment is needed for liver disease.
D. It blocks the conversion of T4 to T3.
E. A and D are true
A
- Why should critically ill patients with nonthyroidal illness (“euthyroid sick syndrome”) and a low serum T4 level not be treated with LT4?
A. The alteration in the thyroid axis is an appropriate physiologic response to metabolic stress.
B. Liothyronine (T3) is the preferred treatment
C. There is no intravenous form of LT4 to administer in the ICU.
D. The low serum T4 improves patient outcomes.
E. A and D are true
D
A 36-year-old, 68-kg (150 lb) female presents to your pharmacy clinic complaining of 2 months of fatigue, menorrhagia, and occasional constipation. Her vital signs are normal, and she is otherwise healthy. Her only medications are a hormonal contraceptive, daily multivitamin product and prn Tums® (calcium carbonate) for heartburn.
- The best test/approach for assessing this patient for hypothyroidism is:
A. Measure serum T 3 and T 4 levels
B. Measure serum TSH (thyrotropin) level and FT 4 (free thyroxine)
C. An empiric trial of levothyroxine
D. An empiric trial of levothyroxine and ferrous sulfate
B
Option B: Correct. TSH is the gold standard test for screening, diagnosing, and monitoring patients for both hypo- and hyperthyroidism. Since the patient is symptomatic, many clinicians
would also order a FT 4 to further confirm a diagnosis of hypothyroidism.
A 36-year-old, 68-kg (150 lb) female presents to your pharmacy clinic complaining of 2 months of fatigue, menorrhagia, and occasional constipation. Her vital signs are normal, and she is otherwise healthy. Her only medications are a hormonal contraceptive, daily multivitamin product and prn Tums® (calcium carbonate) for heartburn.
- If this patient has mild or subclinical hypothyroidism, which therapy has been shown in clinical trials to improve patient outcomes?
A. Liothyronine (LT 3 )
B. Levothyroxine (LT 4 )
C. T 3 and T 4 combination therapy
D. None of the above
- Answer: D
Option D: Correct. There is no strong evidence that any thyroid replacement therapy improves quality of life or thyroid symptoms in patients with subclinical hypothyroidism.
A 36-year-old, 68-kg (150 lb) female presents to your pharmacy clinic complaining of 2 months of fatigue, menorrhagia, and occasional constipation. Her vital signs are normal, and she is
otherwise healthy. Her only medications are a hormonal contraceptive, daily multivitamin product and prn Tums® (calcium carbonate) for heartburn.
- What is the target TSH range for this patient’s therapy?
A. Undetectable (<0.1 mIU/L [µIU/mL]
B. 0.5 to 4.5 mIU/L [µIU/mL]
C. 0.5 to 2.5 mIU/L [µIU/mL]
D. Greater than 4.5 mIU/L [µIU/mL]
- Answer: C
Option C: Correct. This is the range in which risks are minimized and benefits are maximized.
A 36-year-old, 68-kg (150 lb) female presents to your pharmacy clinic complaining of 2 months of fatigue, menorrhagia, and occasional constipation. Her vital signs are normal, and she is otherwise healthy. Her only medications are a hormonal contraceptive, daily multivitamin product and prn Tums® (calcium carbonate) for heartburn.
- If this patient has overt hypothyroidism, what would be the full LT 4 replacement dose?
A. 50 mcg
B. 75 mcg
C. 100 mcg
D. 137 mcg
- Answer: C
Option C: Correct. This is the correct full replacement dose (rounded to common tablet size), 1.6
mcg/kg/day.
A 36-year-old, 68-kg (150 lb) female presents to your pharmacy clinic complaining of 2 months of fatigue, menorrhagia, and occasional constipation. Her vital signs are normal, and she is
otherwise healthy. Her only medications are a hormonal contraceptive, daily multivitamin product and prn Tums® (calcium carbonate) for heartburn.
- If the patient is receiving LT 4 replacement and is started on chronic proton pump inhibitor (PPI) therapy for gastroesophageal reflux disease, what potential impact might the PPI have on
her therapy?
A. Increased LT 4 dose requirement
B. Decreased LT 4 dose requirement
C. Increased risk of PPI adverse drug events
D. Increased risk of failure of her hormonal contraceptive
- Answer: A
Option A: Correct. Decreased gastric acid and elevated gastric pH may reduce the absorption of
LT 4 tablets.
- Levothyroxine products should not be substituted at refill because:
A. No marketed products are AB rated by the FDA Orange Book.
B. All state regulations prohibit the substitution of narrow therapeutic index (NTI) drugs.
C. Small differences in bioavailability may result in loss of disease control.
D. Brand name LT 4 products are inherently better than generics.
C
- A 32-year-old female with stable hypothyroidism, treated with LT 4 100 mcg/day, becomes pregnant. What change will most likely need to be made in her LT 4 therapy?
A. Reduce the dose to 50 mcg
B. No change in dose
C. Increase the dose to 125 mcg/day
D. Increase the dose to 200 mcg/day
C
Option C: Correct. Most patients will require a 20% to 30% increase in dose.
- After the above patient with hypothyroidism delivers her baby, what change will most likely need to be made to her LT 4 dose?
A. Maintain the dose she used while pregnant for at least 6 months
B. Return to her prepregnancy dose
C. Increase her dose by two tablets per week
D. Reduce the dose by 50%
- Answer: B
Option B: Correct. Most patients can return to their prepregnancy dose immediately after delivery. Most patients require a 20% to 30% dose increase during pregnancy.
- Which anticancer agents are associated with a significant risk of causing thyroid dysfunction?
A. Anthracyclines such as doxorubicin
B. Antimetabolites such as methotrexate
C. Immune checkpoint inhibitors such as nivolumab
D. Angiogenesis inhibitors such as bevacizumab
C
- In what setting of antithyroid therapy would PTU be used preferentially over MMI?
A. Patient with a history of MMI-associated agranulocytosis.
B. Patient with adherence issues since PTU is given once daily.
C. Patient with chronic kidney disease.
D. Patient in the first trimester of pregnancy.
D
- Why should critically ill patients with nonthyroidal illness (“euthyroid sick syndrome”) and a low serum T 4 level not be treated with LT 4 ?
A. The alteration in the thyroid axis is an appropriate physiologic response to metabolic stress.
B. Levothyroxine (LT 4 ) will not effectively manage this syndrome.
C. There is no intravenous (IV) form of LT 4 to administer in the ICU.
D. The low serum T 4 improves patient outcomes.
A
Option A: Correct. In severe illness, downregulation of the thyroid axis is thought to be an
appropriate physiologic response.
Option B: Incorrect. There is no evidence that LT 4 administration improves outcomes in patients
who are not truly hypothyroid.
Option C: Incorrect. An IV formulation of LT 4 is available.
Option D: Incorrect. Low serum T 4 is a marker for worse outcomes in critically ill patients.
The following case should be used to answer questions 12 and 13. An 82-year-old, 56-kg (123 lb) female is diagnosed with hypothyroidism. She has a history of hypertension and atrial fibrillation. Current medications include apixaban 2.5 mg bid, metoprolol tartrate 25 mg bid, lisinopril 20 mg qday, calcium carbonate 500 mg qday, Vitamin D3 5000 IU qday, and a multivitamin with iron qday.
- Which of the following is an appropriate LT 4 starting dose for this patient?
A. 25 mcg
B. 50 mcg
C. 75 mcg
D. 100 mcg
A
The following case should be used to answer questions 12 and 13. An 82-year-old, 56-kg (123 lb) female is diagnosed with hypothyroidism. She has a history of
hypertension and atrial fibrillation. Current medications include apixaban 2.5 mg bid, metoprolol tartrate 25 mg bid, lisinopril 20 mg qday, calcium carbonate 500 mg qday, Vitamin D3 5000 IU qday, and a multivitamin with iron qday.
- With her current medications, what is the best time for the patient to take her LT 4 ?
A. 2 hours before breakfast
B. In the morning with calcium and iron supplements
C. At noon with lunch
D. At bedtime
D
Option D: Correct. Bioavailability may be best with bedtime administration.
- A 26-year-old female with anxiety, tremor, weight loss, and tachycardia is diagnosed with Graves’ disease. Which medication will provide the quickest improvement in her symptoms?
A. PTU
B. MMI
C. Propranolol
D. Lugol’s solution
C
- A 19-year-old female with tremor, weight loss, and tachycardia is diagnosed with Graves’ disease. Her TSH level is undetectable and free T 4 level is elevated. She is treated with MMI. One month later, she is complaining of fever and sore throat. Based on these symptoms, your immediate concern is MMI-associated _____________.
A. Hepatitis
B. Agranulocytosis
C. ANCA-positive vasculitis
D. Lupus
B
