Management of Hyperthyroidism: Multiple Choice Questions
Question 1: Initial Symptomatic Management
A 32-year-old woman presents with palpitations, tremor, and heat intolerance. Labs confirm hyperthyroidism with suppressed TSH and elevated free T4. What is the most appropriate initial symptomatic treatment while determining the underlying etiology?
A) Start methimazole 30 mg daily
B) Start propylthiouracil 300 mg three times daily
C) Start atenolol 25-50 mg daily or propranolol
D) Refer immediately for radioactive iodine ablation
E) Observe without treatment
Correct Answer: C
Explanation: Beta-blocker therapy (atenolol 25-50 mg daily or propranolol) should be initiated immediately for symptomatic relief in patients with mild hyperthyroidism while determining definitive treatment. 1 Beta-blockers effectively manage cardiac symptoms like tachycardia and tremor while waiting for antithyroid medications to take effect. 2 This approach provides rapid symptom control regardless of the underlying etiology and is recommended before confirming whether the patient has Graves disease, toxic nodular goiter, or thyroiditis. 1
Question 2: First-Line Antithyroid Drug Selection
A 28-year-old non-pregnant woman with newly diagnosed Graves disease requires antithyroid drug therapy. She has no contraindications to either medication. Which antithyroid drug should be prescribed?
A) Propylthiouracil
B) Methimazole
C) Either drug is equally appropriate
D) Potassium perchlorate
E) Lithium carbonate
Correct Answer: B
Explanation: Methimazole is the preferred antithyroid drug for most patients with hyperthyroidism. 1 Methimazole is favored because it has a longer half-life allowing once-daily dosing, fewer severe side effects compared to propylthiouracil, and better availability. 3 Propylthiouracil should be reserved for patients who cannot tolerate methimazole and in whom radioactive iodine therapy or surgery are not appropriate. 4 The only exception is during the first trimester of pregnancy, when propylthiouracil is preferred. 1, 4
Question 3: Antithyroid Drug in First Trimester Pregnancy
A 26-year-old woman at 8 weeks gestation is diagnosed with Graves disease causing symptomatic hyperthyroidism. Which antithyroid medication should be prescribed?
A) Methimazole throughout pregnancy
B) Propylthiouracil in first trimester, then switch to methimazole
C) Radioactive iodine therapy
D) No treatment until after delivery
E) Beta-blockers alone
Correct Answer: B
Explanation: Propylthiouracil may be the treatment of choice during or just prior to the first trimester of pregnancy, with consideration for switching to methimazole for the second and third trimesters given maternal hepatotoxicity risk. 1 While methimazole may be associated with rare fetal abnormalities (aplasia cutis, choanal/esophageal atresia), propylthiouracil carries significant risk of maternal hepatotoxicity including liver failure. 4 The strategy of using propylthiouracil in the first trimester when organogenesis occurs, then switching to methimazole for the remainder of pregnancy, balances fetal and maternal risks. 1 The goal is maintaining free T4 in the high-normal range using the lowest possible thioamide dosage, with monitoring every 2-4 weeks. 1
Question 4: Management of Thyroiditis-Induced Thyrotoxicosis
A 35-year-old woman presents with thyrotoxicosis. Thyroid uptake scan shows diffusely decreased uptake consistent with thyroiditis. TSH receptor antibodies are negative. What is the most appropriate management?
A) Start methimazole 20 mg daily
B) Immediate radioactive iodine ablation
C) Beta-blockers for symptom relief with close monitoring
D) High-dose corticosteroids
E) Urgent thyroidectomy
Correct Answer: C
Explanation: Thyroiditis is self-limited and typically resolves within weeks with supportive care, most often transitioning to primary hypothyroidism; treat with beta-blockers for symptomatic relief only. 1 Antithyroid drugs are not indicated because thyroiditis involves passive release of preformed thyroid hormones rather than increased synthesis. 1 High-dose corticosteroids are not routinely required. 1 The critical management principle is monitoring thyroid function every 2-3 weeks to detect transition to hypothyroidism, which commonly occurs, and initiating thyroid hormone replacement when TSH becomes elevated with low free T4. 1
Question 5: Monitoring During Antithyroid Drug Therapy
A patient started on methimazole for Graves disease returns for follow-up. What is the appropriate monitoring schedule for thyroid function tests during routine follow-up?
A) Weekly for the first month
B) Every 2-3 weeks initially, then every 4-6 weeks
C) Monthly for 6 months
D) Every 3 months
E) Only when symptoms change
Correct Answer: B
Explanation: Monitor thyroid function every 2-3 weeks initially to detect transition to hypothyroidism, then every 4-6 weeks during routine follow-up. 1 This frequent early monitoring is essential because thyrotoxicosis can persist or transition to hypothyroidism, particularly with thyroiditis. 1 If thyrotoxicosis persists beyond 6 weeks, endocrine consultation should be obtained for additional workup. 1 During pregnancy, even more frequent monitoring (every 2-4 weeks) is required with the goal of maintaining free T4 in the high-normal range. 1
Question 6: Propylthiouracil Black Box Warning
What is the most serious adverse effect that led to a black box warning for propylthiouracil?
A) Agranulocytosis
B) Severe liver injury and acute liver failure
C) Vasculitis
D) Thrombocytopenia
E) Hypothyroidism
Correct Answer: B
Explanation: Severe liver injury and acute liver failure, in some cases fatal, have been reported in patients treated with propylthiouracil, including cases requiring liver transplantation in adult and pediatric patients. 4 This black box warning emphasizes that propylthiouracil should be reserved for patients who cannot tolerate methimazole and in whom radioactive iodine therapy or surgery are not appropriate. 4 Patients should be instructed to report symptoms of hepatic dysfunction immediately, particularly anorexia, pruritus, jaundice, light-colored stools, dark urine, and right upper quadrant pain, especially in the first six months of therapy. 4 Postmarketing reports of severe liver injury including hepatic failure requiring liver transplantation or resulting in death have been particularly concerning in the pediatric population. 4
Question 7: Contraindication to Radioactive Iodine
In which clinical scenario is radioactive iodine therapy absolutely contraindicated?
A) Age over 65 years
B) Pregnancy
C) Mild Graves ophthalmopathy
D) Previous thyroid surgery
E) Concurrent beta-blocker use
Correct Answer: B
Explanation: Radioactive iodine therapy is contraindicated during pregnancy. 2 It should also be avoided during lactation, and pregnancy should be avoided for 4 months following its administration. 5 Radioactive iodine can be used in all age groups other than children. 5 While radioactive iodine may cause deterioration in Graves ophthalmopathy, this is not an absolute contraindication; corticosteroid cover may reduce the risk of this complication. 5 Patients who undergo radioactive iodine therapy often develop hypothyroidism requiring lifelong thyroid hormone replacement. 2
Question 8: Urgent Symptoms Requiring Immediate Reporting
A patient on propylthiouracil therapy should be instructed to report which symptom immediately as it may indicate a life-threatening complication?
A) Mild weight loss
B) Sore throat and fever
C) Mild tremor
D) Increased appetite
E) Mild fatigue
Correct Answer: B
Explanation: Patients receiving propylthiouracil should immediately report any evidence of illness, particularly sore throat, skin eruptions, fever, headache, or general malaise, as these may indicate agranulocytosis. 4 Low white blood cell counts usually occur within the first 3 months of treatment and can be life-threatening, with increased risk of infection. 4 White blood cell and differential counts should be obtained immediately to determine whether agranulocytosis has developed. 4 Other critical symptoms requiring immediate reporting include signs of hepatic dysfunction (anorexia, pruritus, right upper quadrant pain, jaundice, dark urine) and vasculitis (new rash, hematuria, decreased urine output, dyspnea, hemoptysis). 4
Question 9: Diagnostic Workup for Suspected Graves Disease
A patient presents with clinical features of hyperthyroidism including diffuse goiter and exophthalmos. What is the most appropriate next diagnostic step?
A) Thyroid ultrasound
B) TSH receptor antibodies
C) Fine needle aspiration biopsy
D) CT scan of the neck
E) Thyroid peroxidase antibodies only
Correct Answer: B
Explanation: Check TSH receptor antibodies if clinical features suggest Graves disease (ophthalmopathy, diffuse goiter, or T3 toxicosis). 1 Physical examination findings of ophthalmopathy or thyroid bruit are diagnostic of Graves disease and warrant early endocrine referral. 1 Initial biochemical confirmation should include TSH and free T4 testing, with T3 measurement added if symptomatic with minimal free T4 elevation. 1 TSH receptor antibodies are specific for Graves disease and help distinguish it from other causes of hyperthyroidism such as toxic nodular goiter or thyroiditis. 6
Question 10: Surgical Indications for Hyperthyroidism
Which patient with hyperthyroidism has the strongest indication for thyroidectomy?
A) Young woman with mild Graves disease
B) Patient with large goiter causing dysphagia and orthopnea
C) Elderly patient with subclinical hyperthyroidism
D) Patient with thyroiditis
E) Patient preferring medical management
Correct Answer: B
Explanation: Near-total or total thyroidectomy is recommended for patients with large goiters, suspicious nodules, or severe ophthalmopathy. 2 Patients with toxic nodules may have symptoms from local compression of structures in the neck by the thyroid gland, such as dysphagia, orthopnea, or voice changes, which are indications for surgical intervention. 6 Surgery has limited but specific roles in hyperthyroidism treatment and is rarely used in patients with Graves disease unless radioactive iodine has been refused or there is a large goiter causing compressive symptoms. 5 Thyroidectomy requires lifelong thyroid hormone replacement post-surgery. 2