Thyroid disorders

Question 1

Name three risk factors for hyperthyroidism.

Answer 1

• Goiter
• Type 1 Diabetes Mellitus (T1DM)
• Autoimmune history

Other risk factors include family history and certain medications.

Question 2

What is the most specific antibody in Graves disease?

Answer 2

TSH receptor antibody (TRAb)

TRAb is crucial for the diagnosis of Graves disease.

Question 3

What is the typical laboratory finding in hyperthyroidism?

Answer 3

↓ TSH, ↑ FT4 + ↑ total T3

These findings are indicative of hyperthyroidism.

Question 4

In the context of thyroid storm, what is a cardinal symptom?

Answer 4

Fever

Fever is a key indicator of thyroid storm severity.

Question 5

What is the most likely etiology for patchy nodular uptake on RAIU?

Answer 5

Toxic multinodular goiter

This condition is characterized by multiple areas of uptake.

Question 6

What is the diagnosis for a patient with a single ‘hot’ nodule on RAIU?

Answer 6

Toxic adenoma

A toxic adenoma typically presents as a single hyperfunctioning nodule.

Question 7

What is the TSH threshold that mandates treatment in subclinical hyperthyroidism?

Answer 7

TSH < 0.1 mIU/L

This threshold indicates a need for intervention.

Question 8

What is the second-line treatment for primary hyperthyroidism?

Answer 8

• Radioactive Iodine
• Subtotal thyroidectomy

Radioactive iodine is often used for its high cure rate.

Question 9

Name two classic eye findings associated with Graves disease.

Answer 9

• Lid lag
• Proptosis

These findings are characteristic of Graves disease and its effects on the eyes.

Question 10

What is the treatment duration for Methimazole in hyperthyroidism?

Answer 10

12 - 18 months

After this period, treatment can be tapered if asymptomatic and TSH is normal.

Question 11

Aside from TSH-receptor antibody, what other antibody can be positive in hyperthyroidism?

Answer 11

TSI (Thyroid stimulating immunoglobulin)

Question 12

What are THREE common causes of hyperthyroidism?

Answer 12

• Graves’ disease
• Toxic multinodular goiter
• Toxic adenoma
• Thyroiditis (subacute, painless, postpartum)
• Excess thyroid hormone (factitious)
• Amiodarone-induced

These causes highlight the various underlying conditions that can lead to hyperthyroidism.

Question 13

Name THREE clinical features suggestive of Graves’ disease.

Answer 13

• Diffuse goiter
• Ophthalmopathy (proptosis)
• Pretibial myxedema
• Thyroid bruit

These features are characteristic signs that may indicate the presence of Graves’ disease.

Question 14

When is propylthiouracil (PTU) preferred over methimazole? (2)

Answer 14

• First trimester of pregnancy
• Thyroid storm

PTU is often chosen in specific clinical situations due to its safety profile.

Question 15

What are TWO serious adverse effects of antithyroid medications?

Answer 15

• Agranulocytosis
• Hepatotoxicity

These adverse effects can pose significant health risks to patients undergoing treatment.

Question 16

What are THREE components of thyroid storm management?

Answer 16

• Beta-blocker (e.g., propranolol)
• Antithyroid drug (PTU or methimazole)
• Iodine (after antithyroid drug)
• Corticosteroids
• Supportive care (IV fluids, cooling)

Effective management of thyroid storm requires a multi-faceted approach.

Question 17

What are TWO indications for radioactive iodine therapy?

Answer 17

• Relapse after antithyroid drug therapy
• Patient preference for definitive treatment
• Contraindication/intolerance to antithyroid drugs

These indications help determine when radioactive iodine therapy is appropriate.

Question 18

What is one important long-term risk of radioactive iodine therapy?

Answer 18

Permanent hypothyroidism

This risk is a significant consideration when discussing treatment options with patients.

Question 19

What are THREE common causes of primary hypothyroidism in Canada?

Answer 19

• Hashimoto thyroiditis
• Post-thyroidectomy
• Radioactive iodine therapy
• Postpartum thyroiditis
• Medications (amiodarone, lithium)

These causes highlight the various factors leading to primary hypothyroidism.

Question 20

Name THREE symptoms of overt hypothyroidism.

Answer 20

• Fatigue
• Cold intolerance
• Weight gain
• Constipation
• Dry skin
• Bradycardia

Symptoms can vary but often include these common manifestations.

Question 21

When should subclinical hypothyroidism be treated? Name THREE conditions.

Answer 21

• TSH ≥ 10 mIU/L
• Symptomatic patient
• Positive TPO antibodies
• Pregnancy
• Infertility
• Goiter

Treatment considerations depend on specific clinical scenarios.

Question 22

What is the recommended starting approach for levothyroxine in older adults or patients with CAD?

Answer 22

Start low (12.5–25 mcg daily) and titrate every 6–8 weeks

This cautious approach helps mitigate potential risks in vulnerable populations.

Question 23

How often should TSH be rechecked after initiating or adjusting levothyroxine?

Answer 23

Every 6–8 weeks

Regular monitoring is essential to ensure appropriate dosing.

Question 24

Name THREE causes of elevated TSH despite levothyroxine therapy.

Answer 24

• Poor adherence
• Drug interactions (iron, calcium, PPIs)
• Malabsorption (celiac disease)
• Taking medication with food
• Inadequate dose

Identifying these causes is important for effective management of hypothyroidism.

Question 26

List two exceptions where **subclinical hypothyroidism** with TSH <10 mIU/L should be treated.

Answer 26

* Pregnancy * Positive TPO antibodies ## Footnote Other acceptable answers include goitre and strong family history of autoimmune disease.

Question 27

Which thyroid antibody is most specific for **autoimmune hypothyroidism**?

Answer 27

Thyroid peroxidase antibody (TPOAb) ## Footnote TPOAb is a key marker in diagnosing autoimmune thyroid conditions.

Question 28

Name two **cardiovascular findings** that can be seen in **hypothyroidism**.

Answer 28

* Bradycardia * Pericardial effusion ## Footnote Other acceptable answers include CHF and angina.

Question 29

What is the target **TSH level** for a pregnant patient with known hypothyroidism confirmed to be 5 weeks gestation?

Answer 29

<2.5 mIU/L ## Footnote Maintaining this level is crucial for fetal development.

Question 30

Name one medication or supplement that can interfere with **levothyroxine absorption**.

Answer 30

Calcium ## Footnote Other acceptable answers include iron, cholestyramine, antacids, PPI, and anticonvulsants.

Question 31

Who is at risk for developing **hypothyroidism**? (4)

Answer 31

* Women * ↑ age (45 - 50 y/o) * Pregnant during 1st trimester * Postpartum (6w - 6mo) * All adults * On meds (amiodarone, lithium, iodine) * FHx of thyroid disease or autoimmune disorder * Personal autoimmune disease * Prior neck radiation ## Footnote These factors contribute to the likelihood of developing thyroid dysfunction.