Block 13 Thyroid Disorders And Drugs MCQ's
The thyroid is charged with producing, storing and releasing hormones into the blood stream. If this function is not carried out as planned it may result in a number of disorders. Review what you learnt on Block 13 on thyroid disorders and drugs by taking this quiz. All the best!
Questions and Answers
- 1.
A 60-year-old woman presents with complaints of feeling nervous, moody, weak, and tired. On exam, she has hand tremors and a rapid heartbeat. Pulse 120/min. BP 110/78. She has been taking levothyroxine for hypothyroidism, and you suspect that she is taking more tablets than you prescribed. Which of the following sets of laboratory results is most consistent with her clinical presentation? A B C D E TSH Elevated Normal Elevated Normal Decreased T4 Elevated Elevated Decreased Decreased Elevated T3 Elevated Decreased Decreased Decreased Elevated
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
E. EExplanation
The correct answer is E. In this scenario, the woman is experiencing symptoms of hyperthyroidism, which is consistent with an elevated T3 level. Hyperthyroidism is characterized by an overactive thyroid gland, leading to an increase in the production and release of thyroid hormones. This results in symptoms such as nervousness, moodiness, weakness, and fatigue. The hand tremors and rapid heartbeat are also common signs of hyperthyroidism. The normal TSH and elevated T4 levels further support the diagnosis of hyperthyroidism.Rate this question:
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- 2.
A 50 year old man presents with a thyroid neoplasm. Detailed history elicits that his aunt had died from a “thyroid illness”. His family and first order blood relatives are examined. His sister and a nephew also are found to have small thyroid tumors. His son is found to have a pheochromocytoma. Which of the following gene mutations are most likely to be associated with this condition?
- A.
PTTG
- B.
Cyclin D
- C.
Ret
- D.
MEN 1
- E.
TBG
Correct Answer
C. RetExplanation
The presence of thyroid neoplasms in the patient, his sister, and nephew, along with the presence of a pheochromocytoma in his son, suggests a hereditary condition. The most likely gene mutation associated with this condition is RET (rearranged during transfection). RET gene mutations are commonly associated with multiple endocrine neoplasia type 2 (MEN 2), which is characterized by the development of thyroid tumors (medullary thyroid carcinoma) and pheochromocytoma. Therefore, the correct answer is RET.Rate this question:
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- 3.
A 34 year old man reports to your office complaining of weight loss and sweating. Among other findings you note the following, while examining his extraocular movements: What do we call this finding?
- A.
Proptosis
- B.
Ophthalmoplegia
- C.
Lid lag
- D.
Trochlear nerve palsy
- E.
Levator palpebrae dysfunction
Correct Answer
C. Lid lagExplanation
Lid lag refers to a delay in the downward movement of the upper eyelid during downward gaze. This finding is commonly seen in patients with hyperthyroidism, which can cause weight loss and sweating. It is important to note this finding during the examination as it can be indicative of thyroid dysfunction.Rate this question:
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- 4.
A 44-year-old African American man presents to his family physician with a neck lump he noticed while shaving this morning. Physical examination reveals a 1 cm well-defined firm nodule in the right thyroid lobe. The mass is resected and sent for histopathologic examination. The microscopic appearance of the lesion is shown for your evaluation below. Elevation of which of the following serum markers can you expect in this patient?
- A.
Thyroid stimulating hormone
- B.
Calcitonin
- C.
Thyroglobulin
- D.
Carcinoembryonic antigen
Correct Answer
C. ThyroglobulinExplanation
Thyroglobulin is a protein produced by the thyroid gland. Elevation of thyroglobulin in the serum can be expected in patients with thyroid cancer. In this case, the patient presents with a neck lump and a well-defined nodule in the right thyroid lobe, which is suggestive of thyroid cancer. Therefore, it is likely that the histopathologic examination of the resected mass will reveal thyroid cancer, leading to an elevation of thyroglobulin in the serum. Thyroid stimulating hormone (TSH) is not expected to be elevated in this case, as it is typically suppressed in thyroid cancer. Calcitonin and carcinoembryonic antigen are not specific markers for thyroid cancer.Rate this question:
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- 5.
A 43-year-old Caucasian man presents to his family physician with a neck lump he noticed while shaving this morning. Physical examination reveals a 0.5 cm ill-defined firm nodule in the left thyroid lobe. Laboratory investigations reveal an elevated serum level of carcinoembryonic antigen, serotonin, parathormone, and calcitonin. 99mTechnetium thyroid scan and fine needle aspiration biopsy of the nodule is performed and the patient undergoes thyroidectomy. The thyroid scan and histology of the lesion are presented for your evaluation. Which of the following clinical syndromes is most likely to be found in this patient?
- A.
Acromegaly
- B.
Diabetes insipidus
- C.
Severe hypertension
- D.
Myxedema
Correct Answer
C. Severe hypertensionExplanation
The patient in this scenario is most likely to have a clinical syndrome of severe hypertension. This is indicated by the elevated serum levels of carcinoembryonic antigen, serotonin, parathormone, and calcitonin, as well as the presence of a 0.5 cm ill-defined firm nodule in the left thyroid lobe. These findings suggest that the patient may have a thyroid tumor, specifically a medullary thyroid carcinoma, which is known to be associated with the secretion of excessive amounts of calcitonin. Elevated calcitonin levels can lead to severe hypertension, making this the most likely clinical syndrome in this patient.Rate this question:
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- 6.
Individuals with hypothyroidism would mostly likely have which one of the following conditions?
- A.
Growth retardation if occurs during the perinatal period
- B.
Increased cardiac output
- C.
Weight loss
- D.
Excessive production of TSH if the defect is in the hypothalamus
- E.
Less than normal levels of cholesterol in the circulation
Correct Answer
A. Growth retardation if occurs during the perinatal periodExplanation
Individuals with hypothyroidism would mostly likely have growth retardation if it occurs during the perinatal period. Hypothyroidism is a condition where the thyroid gland does not produce enough thyroid hormone, which is essential for normal growth and development. If hypothyroidism occurs during the perinatal period (the time immediately before and after birth), it can lead to impaired growth and development, resulting in growth retardation.Rate this question:
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- 7.
Iodine deficiency used to be a common cause of thyroid enlargement (goiter) in some parts of the world. Which abnormality in chronically iodine-deficient patients is most directly related to the enlargement of the thyroid gland?
- A.
Reduced activity of thyroperoxidase
- B.
Impaired conversion of T4 to T3
- C.
Reduced level of cAMP in the thyroid follicular cells
- D.
An antibody that binds to the TSH receptor in the thyroid gland
- E.
Elevated TSH level
Correct Answer
E. Elevated TSH levelExplanation
In chronically iodine-deficient patients, the thyroid gland enlarges due to a compensatory response to low levels of thyroid hormone production. When iodine levels are low, the thyroid gland is unable to produce sufficient amounts of thyroid hormones T3 and T4. As a result, the pituitary gland releases more thyroid-stimulating hormone (TSH) to stimulate the thyroid gland to produce more hormones. Therefore, an elevated TSH level is most directly related to the enlargement of the thyroid gland in iodine-deficient patients.Rate this question:
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- 8.
Which of the following effects may be caused high plasma levels of thyroid hormones? (Check all that apply)
- A.
Decreased cardiac output
- B.
Increased gluconeogenesis
- C.
Decreased plasma levels of triglycerides
- D.
Decreased plasma levels of free fatty acids
- E.
Increased pulse pressure
- F.
Decreased intestinal peristalsis
Correct Answer(s)
B. Increased gluconeogenesis
C. Decreased plasma levels of triglycerides
E. Increased pulse pressureExplanation
High plasma levels of thyroid hormones can lead to increased gluconeogenesis, which is the production of glucose from non-carbohydrate sources. This occurs because thyroid hormones stimulate the breakdown of glycogen and proteins, leading to an increase in glucose production.
Additionally, high levels of thyroid hormones can cause a decrease in plasma levels of triglycerides. This is because thyroid hormones increase the breakdown of triglycerides in adipose tissue, leading to a decrease in their levels in the blood.
Finally, high levels of thyroid hormones can result in increased pulse pressure. Pulse pressure is the difference between systolic and diastolic blood pressure, and it is increased when there is an increase in cardiac output or a decrease in arterial compliance. Thyroid hormones can increase cardiac output, leading to an increase in pulse pressure.Rate this question:
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- 9.
Which of the following effects may be caused by insufficient plasma levels of thyroid hormones? (Check all that apply)
- A.
Oligospermia
- B.
Decreased respiratory rate
- C.
Decreased plasma triglycerides
- D.
Decreased peripheral vascular resistance
- E.
Osteoporosis
- F.
Periorbital edema
- G.
Diarrhea
Correct Answer(s)
A. Oligospermia
B. Decreased respiratory rate
F. Periorbital edemaExplanation
Insufficient plasma levels of thyroid hormones can lead to various effects on the body. Oligospermia refers to a decreased sperm count, which can be caused by hormonal imbalances. Decreased respiratory rate can occur due to a decrease in metabolic activity caused by low thyroid hormone levels. Periorbital edema, or swelling around the eyes, can also be a result of thyroid hormone deficiency. Therefore, oligospermia, decreased respiratory rate, and periorbital edema are all possible effects of insufficient plasma levels of thyroid hormones.Rate this question:
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- 10.
A 42-year-old man was undergoing surgery in order to remove a very large nontoxic goiter, apparently due to iodide deficiency. A short course of potassium iodide was administered before surgery. Which of the following statements best explains why this drug was given to the patient?
- A.
To stimulate thyroid hormone synthesis before surgery
- B.
To overcome iodine deficiency after surgery
- C.
To reduce the size and vascularity of the thyroid gland
- D.
To decrease the risk of hypothyroidism after surgery
- E.
To inhibit the excessive secretion of TSH from the pituitary
Correct Answer
C. To reduce the size and vascularity of the thyroid glandExplanation
Potassium iodide was given to the patient in order to reduce the size and vascularity of the thyroid gland. This is because the patient had a very large nontoxic goiter, which is often caused by iodine deficiency. By administering potassium iodide, the thyroid gland is stimulated to take up more iodine, leading to a decrease in the size and vascularity of the goiter. This treatment is commonly used before surgery to make the removal of the goiter easier and safer.Rate this question:
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- 11.
A 55-year-old woman with thyrotoxicosis was treated with radioactive iodine. One month later she most likely started a therapy with which of the following drugs?
- A.
Potassium iodide
- B.
Levothyroxine
- C.
Diiodotyrosine
- D.
Monoiodotyrosine
- E.
Reverse triiodothyronine
Correct Answer
B. LevothyroxineExplanation
After being treated with radioactive iodine for thyrotoxicosis, the patient's thyroid function would be expected to decrease. Levothyroxine is a synthetic form of the thyroid hormone thyroxine (T4) and is commonly used to replace or supplement the body's natural thyroid hormone. Therefore, it is most likely that the patient would start therapy with levothyroxine to restore normal thyroid function. Potassium iodide is used to block the thyroid from absorbing radioactive iodine and would not be necessary after treatment. Diiodotyrosine, monoiodotyrosine, and reverse triiodothyronine are all metabolites of thyroid hormones and are not typically used in therapy.Rate this question:
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- 12.
A 59-year-old woman was admitted to the hospital with restlessness, insomnia, tremor and a pronounced exophthalmos. The woman, who had been suffering from hyperthyroidism for two months, had been treated with propylthiouracil but the drug was discontinued because of the appearance of agranulocytosis. Which of the following agents would be most appropriate for the patient at this time?
- A.
Methimazole
- B.
Radioactive iodine
- C.
Potassium iodide
- D.
Propranolol
- E.
Prednisone
Correct Answer
B. Radioactive iodineExplanation
Radioactive iodine is the most appropriate agent for the patient at this time because she has been suffering from hyperthyroidism and has developed agranulocytosis as a side effect of propylthiouracil. Radioactive iodine is commonly used to treat hyperthyroidism by destroying the overactive thyroid cells. It is a safe and effective treatment option, especially in cases where antithyroid drugs are contraindicated or not tolerated. Methimazole is another antithyroid drug, but it is not suitable for this patient due to the previous adverse reaction to propylthiouracil. Potassium iodide is used for short-term treatment of hyperthyroidism, but it is not the most appropriate choice in this case. Propranolol is a beta-blocker that can help manage symptoms of hyperthyroidism, but it does not treat the underlying condition. Prednisone is a corticosteroid and is not indicated for the treatment of hyperthyroidism.Rate this question:
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- 13.
A 55-year old woman recently diagnosed with hyperthyroidism started an appropriate treatment. One month later the following laboratory values were obtained: RBC 4.6 x 10 /mcl, WBC 0.9 x 10 /mcl, platelets 45 6 3 x 103/mcl. Which of the following drugs most likely causes these results?
- A.
Radioactive iodine
- B.
Potassium iodide
- C.
Methimazole
- D.
Propranolol
- E.
L-thyroxine
Correct Answer
C. MethimazoleExplanation
Methimazole is an antithyroid drug commonly used to treat hyperthyroidism. One of the side effects of methimazole is bone marrow suppression, which can lead to a decrease in red blood cells (RBC), white blood cells (WBC), and platelets. The laboratory values obtained for this patient, including a low RBC count, low WBC count, and low platelet count, are consistent with the bone marrow suppression caused by methimazole. Therefore, methimazole is the drug most likely responsible for these results.Rate this question:
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- 14.
Few days after a normal delivery, a new born baby boy became lethargic, had respiratory difficulties, hoarse cry, and sucks poorly. Physical examination revealed large fontanelles, macroglossia, a distended abdomen, a cyanotic skin, hypotonia, slow reflexes and hypothermia. Which of the following drugs would be appropriate for this baby?
- A.
Methimazole
- B.
Somatrem
- C.
Levothyroxine
- D.
Theophylline
- E.
Potassium iodide
- F.
Prednisone
Correct Answer
C. LevothyroxineExplanation
The symptoms described in the question, such as large fontanelles, macroglossia, distended abdomen, cyanotic skin, hypotonia, slow reflexes, and hypothermia, are indicative of hypothyroidism in a newborn. Levothyroxine is a synthetic form of thyroid hormone and is the appropriate drug for treating hypothyroidism. Methimazole is used to treat hyperthyroidism, not hypothyroidism. Somatrem is a growth hormone, which is not relevant to the symptoms described. Theophylline is a bronchodilator used to treat respiratory conditions, but it is not appropriate for the symptoms described. Potassium iodide is used to treat iodine deficiency, not hypothyroidism. Prednisone is a corticosteroid used to treat inflammation, but it is not appropriate for the symptoms described.Rate this question:
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- 15.
A 35 year old woman, who was 2 months pregnant, was found to have FT4 of 3.3 ng/dL (normal 0.9-2) and TSH < 0.01 IU/mL (normal 0.5-4.7) during a follow up visit. Which of the following chronic drug treatment would be most appropriate for this patient?
- A.
Radioactive iodine
- B.
Propranolol
- C.
Potassium iodide
- D.
Ipodate
- E.
Propylthiouracil
Correct Answer
E. PropylthiouracilExplanation
The correct answer is Propylthiouracil because the patient's FT4 level is elevated, indicating hyperthyroidism. Propylthiouracil is an antithyroid medication that inhibits the production of thyroid hormones, therefore it would be the most appropriate treatment option for this patient. Radioactive iodine, potassium iodide, and ipodate are used in the treatment of hyperthyroidism, but they are contraindicated in pregnancy. Propranolol is a beta-blocker that can help manage symptoms of hyperthyroidism, but it does not treat the underlying condition.Rate this question:
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- 16.
A 75-year-old woman came to the clinic for her regular checkup. Her only complaints included very dry skin and constipation which she treats with milk of magnesia. She had no other medical problems and took no other medications. Routine laboratory tests are within normal limits except for a TSH of 15 mIU/mL (normal 0.5-5.5). Further lab exams indicated the presence of thyroid peroxidase antibodies. Which of the following drug would be appropriate for this patient?
- A.
Potassium iodide
- B.
Propranolol
- C.
Methimazole
- D.
Loperamide
- E.
Levothyroxine
- F.
Diltiazem
Correct Answer
E. LevothyroxineExplanation
Levothyroxine would be appropriate for this patient because she has an elevated TSH level and the presence of thyroid peroxidase antibodies, indicating hypothyroidism. Levothyroxine is a synthetic form of thyroid hormone that can effectively treat hypothyroidism by replacing the deficient hormone. The other options, such as potassium iodide, propranolol, methimazole, loperamide, and diltiazem, are not indicated for treating hypothyroidism and would not address the underlying cause of the patient's symptoms.Rate this question:
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- 17.
A 60-year-old alcoholic woman was admitted to the emergency room because of unrelenting chest pain not relieved by nitroglycerin. Her medical problems included alcoholic cardiomyopathy and hypothyroidism. Although she had been advised repeatedly to take her thyroxine regularly she continued to take it sporadically. An IM injection of 10 mg of morphine sulphate was given for the pain. After the injection the nurse noticed mental depression, lethargy, shallow breathing and her temperature was 80E F. Which of the following drugs should be included in the emergency therapy of this patient?
- A.
IV potassium iodide
- B.
Oral methimazole
- C.
Oral levothyroxine
- D.
IV triiodothyronine
- E.
Oral propylthiouracil
Correct Answer
D. IV triiodothyronineExplanation
The patient in this scenario has hypothyroidism, which is a condition characterized by low levels of thyroid hormones. The symptoms mentioned, such as mental depression, lethargy, and low body temperature, are consistent with severe hypothyroidism, also known as myxedema coma. IV triiodothyronine (T3) is the most appropriate emergency therapy for this condition as it provides immediate replacement of thyroid hormones. The other options, such as IV potassium iodide, oral methimazole, oral levothyroxine, and oral propylthiouracil, are not indicated in the emergency treatment of myxedema coma.Rate this question:
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- 18.
A 41-year-old man complained to his physician of increased appetite, palpitation and diarrhea. Lab results confirmed the diagnosis of mild hyperthyroidism and a treatment with methimazole was started. Which of the following actions most likely mediated the therapeutic effectiveness of the drug in this patient?
- A.
Inhibition of iodine absorption from the gut
- B.
Stimulation of thyroid peroxidase
- C.
Blockade of iodine uptake by the thyroid gland
- D.
Damage of DNA of thyroid cells
- E.
Inhibition of tyrosine iodination
Correct Answer
E. Inhibition of tyrosine iodinationExplanation
Methimazole is a medication used to treat hyperthyroidism by inhibiting the production of thyroid hormones. It does this by specifically inhibiting the process of tyrosine iodination, which is a crucial step in the synthesis of thyroid hormones. By inhibiting tyrosine iodination, methimazole reduces the production of thyroid hormones, leading to a decrease in symptoms such as increased appetite, palpitation, and diarrhea.Rate this question:
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- 19.
A 47-year-old woman complained to her physician of painless enlargement of thyroid gland and fullness in her throat. Lab results revealed high titers of thyroid peroxidase antibodies. A diagnosis of Hashimoto’s thyroiditis was made and an appropriate treatment was started. Which of the following drugs was most likely prescribed?
- A.
Propranolol
- B.
Potassium iodide
- C.
Levothyroxine
- D.
Methimazole
- E.
Radioactive iodine
Correct Answer
C. LevothyroxineExplanation
The correct answer is Levothyroxine because Hashimoto's thyroiditis is an autoimmune condition where the thyroid gland is attacked by the body's own immune system. This leads to decreased production of thyroid hormones, resulting in an underactive thyroid (hypothyroidism). Levothyroxine is a synthetic form of the thyroid hormone thyroxine, which is used to replace the deficient thyroid hormone in hypothyroidism. It helps to restore normal thyroid hormone levels and alleviate the symptoms of Hashimoto's thyroiditis.Rate this question:
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- 20.
Which of the following drugs can block most effectively the conversion of T4 to T3 by the liver?
- A.
Levothyroxine
- B.
Diiodotyrosine
- C.
Methimazole
- D.
Propylthiouracil
- E.
TSH
Correct Answer
D. PropylthiouracilExplanation
Propylthiouracil is the correct answer because it is an antithyroid medication that inhibits the conversion of T4 to T3 by the liver. This drug is commonly used in the treatment of hyperthyroidism to reduce the production of thyroid hormones. Methimazole is also an antithyroid medication but it does not block the conversion of T4 to T3 as effectively as propylthiouracil. Levothyroxine is a thyroid hormone replacement medication and does not inhibit the conversion of T4 to T3. Diiodotyrosine is a precursor to thyroid hormones and does not have an inhibitory effect on the conversion process. TSH (thyroid-stimulating hormone) is not a drug and does not have any direct effect on the conversion of T4 to T3.Rate this question:
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.JPG "A 34 year old man reports to your office complaining of weight loss and sweating. Among other findings you note the following, while examining his extraocular movements:
What do we call this finding?")
.JPG "A 44-year-old African American man presents to his family physician with a neck lump he noticed while shaving this morning. Physical examination reveals a 1 cm well-defined firm nodule in the right thyroid lobe. The mass is resected and sent for histopathologic examination. The microscopic appearance of the lesion is shown for your evaluation below. Elevation of which of the following serum markers can you expect in this patient?")
.JPG "A 43-year-old Caucasian man presents to his family physician with a neck lump he noticed while shaving this morning. Physical examination reveals a 0.5 cm ill-defined firm nodule in the left thyroid lobe. Laboratory investigations reveal an elevated serum level of carcinoembryonic antigen, serotonin, parathormone, and calcitonin. 99mTechnetium thyroid scan and fine needle aspiration biopsy of the nodule is performed and the patient undergoes thyroidectomy. The thyroid scan and histology of the lesion are presented for your evaluation. Which of the following clinical syndromes is most likely to be found in this patient?")
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Mar 21, 2023Quiz Edited by
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Sep 13, 2012Quiz Created by
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