Thyroid Disorders — MCQs
Which of the following conditions is the most common complication of radioiodine treatment for Graves' disease?
Which of the following is the most useful investigation for thyroid function?
Which of the following is a common laboratory finding in hypothyroidism?
What is the primary effect of beta blockers in the management of thyroid storm?
A 17-year-old woman presents with symptoms of a fine tremor of her hands. The tremor is best seen when her hands are stretched out. She is not on any medications and reports no alcohol use. Which of the following is the most likely diagnosis?
A 30-year-old female complaints of fatigue and is unable to gain weight. On examination, her body felt warm. Which of the following investigation can be helpful in reaching the diagnosis?
A patient presents with symptoms of hyperthyroidism. Thyroid function tests would probably reveal:
A 65 year old female presents with a swelling in the neck diagnosed as a solitary thyroid nodule. The patient is investigated and a scan shows increased uptake of iodine. Serum T3 and T4 are elevated . Most probabe diagnosis is
A patient presents with headaches, palpitations, hypertension, and urine VMA positivity. The biopsy findings are shown in the image. Which of the following statements is correct?
Preoperative medication of thyrotoxicosis are all except?
Thyroid Disorders Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following conditions is the most common complication of radioiodine treatment for Graves' disease?
- A. Hypothyroidism (Correct Answer)
- B. Thyroid cancer
- C. Thyroid storm
- D. Subacute thyroiditis
Explanation: ***Hypothyroidism*** - **Radioiodine (RAI) therapy** destroys overactive thyroid cells, making it highly effective for Graves' disease but often leading to a permanent state of **hypothyroidism** post-treatment. - The goal of RAI is to eliminate the source of excess hormone production, and while effective, it frequently necessitates lifelong **thyroid hormone replacement**. *Thyroid storm* - **Thyroid storm** is a rare, life-threatening complication, usually seen in untreated or undertreated hyperthyroidism or during acute stress, not typically a direct outcome of effective RAI. - While a transient increase in thyroid hormones can occur shortly after RAI, a full-blown thyroid storm is infrequent with proper preparation and management. *Thyroid cancer* - There is no significant evidence to suggest an increased risk of **thyroid cancer** in adults following therapeutic doses of radioiodine for Graves' disease [1]. - The radiation dose is targeted primarily at the thyroid gland, and studies have shown no clear link to increased malignancy [1]. *Subacute thyroiditis* - **Subacute thyroiditis** (also known as de Quervain's thyroiditis) is typically a post-viral inflammatory condition of the thyroid, characterized by pain and tenderness in the thyroid gland [2]. - It does not directly result from radioiodine treatment; however, some patients may experience a transient inflammatory response (radiation thyroiditis) after RAI, which is usually mild and self-limiting, not true subacute thyroiditis.
Question 2: Which of the following is the most useful investigation for thyroid function?
- A. TSH (Correct Answer)
- B. T3
- C. T4
- D. Thyroglobulin
Explanation: TSH - **Thyroid-Stimulating Hormone (TSH)** is the most sensitive and specific test for assessing thyroid function as it reflects the feedback loop between the pituitary gland and the thyroid [1]. - An abnormal TSH level usually indicates either **hypothyroidism** (high TSH) or **hyperthyroidism** (low TSH), even before changes in T3 or T4 are apparent [1]. *T3* - **Triiodothyronine (T3)** is primarily used to confirm a diagnosis of hyperthyroidism, especially when T4 levels are normal but TSH is suppressed [1]. - It is less reliable for initial screening due to its **short half-life** and significant diurnal variation. [1] *T4* - **Thyroxine (T4)** is a good indicator of thyroid hormone production, but its levels can be affected by **protein binding** and non-thyroidal illnesses. - While total T4 is often included in a thyroid panel, **free T4** is more accurate as it reflects the metabolically active hormone not bound to proteins [1]. *Thyroglobulin* - **Thyroglobulin** is primarily used as a tumor marker for monitoring recurrence in patients with differentiated thyroid cancer after thyroidectomy [1]. - It plays no significant role in the initial **assessment of general thyroid function** or diagnosis of hyper/hypothyroidism [1].
Question 3: Which of the following is a common laboratory finding in hypothyroidism?
- A. High TSH (Correct Answer)
- B. Low T3
- C. High cholesterol
- D. High Triglycerides
Explanation: ### High TSH - In **primary hypothyroidism**, the thyroid gland fails to produce adequate thyroid hormones (**T3** and **T4**). [1] - This leads to a compensatory increase in **TSH** release from the pituitary gland, attempting to stimulate the thyroid. [1] *Low T3* - While **low T3** can be present in hypothyroidism, **low free T4** is generally a more sensitive and specific marker for the diagnosis of primary hypothyroidism. [1] - T3 levels can sometimes remain normal or only slightly reduced even in overt hypothyroidism, especially in the early stages. *High cholesterol* - **Elevated cholesterol**, particularly **LDL (low-density lipoprotein)**, is a common metabolic consequence of hypothyroidism due to decreased catabolism of lipids. [2] - However, it is a metabolic complication rather than a direct hormonal lab finding defining hypothyroidism. *High Triglycerides* - **High triglycerides** can also be observed in hypothyroidism due to impaired lipid metabolism and reduced lipoprotein lipase activity. - Similar to elevated cholesterol, it is a metabolic consequence, not a primary diagnostic marker for the thyroid hormone imbalance itself.
Question 4: What is the primary effect of beta blockers in the management of thyroid storm?
- A. Increases metabolism of thyroxine
- B. Blocks thyroxine receptors
- C. Decreases synthesis of thyroxine
- D. Provides rapid relief of symptoms (Correct Answer)
Explanation: Detailed management of thyrotoxic crisis (thyroid storm) is a medical emergency where patients should be given propranolol, either oral or intravenous, to manage life-threatening symptoms [1]. ***Provides rapid relief of symptoms*** - Beta blockers primarily address the **adrenergic manifestations** of thyroid storm, such as **tachycardia**, **tremors**, anxiety, and palpitations [1]. - By blocking **beta-adrenergic receptors**, they provide rapid symptomatic relief and reduce cardiovascular stress, without affecting hormone levels [2]. Thyroid hormones normally increase the expression of genes for beta-adrenergic receptors and G-proteins, leading to increased heart rate and force of contraction [2]. *Increases metabolism of thyroxine* - Beta blockers do not increase the **metabolism** or breakdown of thyroxine; their action is primarily on the **peripheral effects** of thyroid hormones. - While some beta blockers like **propranolol** can inhibit the peripheral conversion of T4 to T3, this is a secondary effect and not their primary role in providing rapid symptomatic relief [1]. *Blocks thyroxine receptors* - Beta blockers do not block **thyroxine receptors**; thyroid hormones exert their effects by binding to intracellular receptors, not adrenergic receptors [2]. - Their action is on the **adrenergic system**, which is overstimulated by the high levels of thyroid hormones. *Decreases synthesis of thyroxine* - Beta blockers do not directly decrease the **synthesis of thyroxine** by the thyroid gland. - That action is performed by **antithyroid drugs** like methimazole and propylthiouracil, which inhibit hormone production [1].
Question 5: A 17-year-old woman presents with symptoms of a fine tremor of her hands. The tremor is best seen when her hands are stretched out. She is not on any medications and reports no alcohol use. Which of the following is the most likely diagnosis?
- A. marijuana use
- B. myxedema
- C. hyperthyroidism (Correct Answer)
- D. hypopituitarism
Explanation: ### Hyperthyroidism - A **fine tremor** that is best observed with **action (postural tremor)**, such as outstretched hands, is a classic feature of hyperthyroidism due to increased adrenergic tone. - Other common symptoms of hyperthyroidism often include **tachycardia**, **anxiety**, **weight loss**, and **heat intolerance** [1], which should be investigated further. *Marijuana use* - While marijuana use can cause tremors, they are typically more related to **intoxication** and less specifically described as a fine postural tremor in an otherwise healthy individual. - Tremors from cannabis are often less sustained and associated with other signs of impairment, such as **altered perception** and **impaired coordination**. *Myxedema* - Myxedema refers to severe **hypothyroidism**, which typically causes a **slowing of motor functions** and can sometimes result in a fine tremor, but this is less common and often less prominent than in hyperthyroidism. - Patients with myxedema usually present with **fatigue**, **weight gain**, **cold intolerance**, and **bradycardia** [1], which are symptoms opposite to those associated with a fine postural tremor dueoved. *Hypopituitarism* - Hypopituitarism involves a **deficiency in multiple pituitary hormones** and generally does not present with a primary symptom of fine hand tremor. - Symptoms vary widely depending on the hormones affected but typically include **fatigue**, **weakness**, **menstrual irregularities**, and **hypotension**, rather than a distinct tremor.
Question 6: A 30-year-old female complaints of fatigue and is unable to gain weight. On examination, her body felt warm. Which of the following investigation can be helpful in reaching the diagnosis?
- A. Elevated TSH with normal thyroid hormone levels
- B. Elevated TSH with low thyroid hormone levels
- C. Normal TSH with abnormal thyroid hormone levels
- D. Suppressed TSH with elevated thyroid hormone levels (Correct Answer)
Explanation: Suppressed TSH with elevated thyroid hormone levels - The patient's symptoms of **fatigue** (despite being warm) and **difficulty gaining weight**, coupled with her body feeling **warm**, are classic signs of **hyperthyroidism**. [1] - In hyperthyroidism, the thyroid gland produces **excessive thyroid hormones (T3 and T4)**, which in turn **suppresses TSH** production from the pituitary gland through negative feedback. [2] *Elevated TSH with normal thyroid hormone levels* - This pattern is characteristic of **subclinical hypothyroidism**, where the thyroid gland is beginning to fail, leading to increased TSH to maintain normal thyroid hormone levels. [3] - The patient's symptoms of feeling warm and difficulty gaining weight are inconsistent with hypothyroidism. [1] *Elevated TSH with low thyroid hormone levels* - This indicates **primary hypothyroidism**, where the thyroid gland is underactive and produces insufficient thyroid hormones, leading to a compensatory rise in TSH. [2] - Hypothyroidism typically presents with **weight gain**, **cold intolerance**, and fatigue, which contradict the patient's presentation. [1] *Normal TSH with abnormal thyroid hormone levels* - This scenario usually suggests **central hypothyroidism** (pituitary or hypothalamic dysfunction affecting TSH production) or **thyroid hormone resistance**. [3] - While possible in some rare cases, it does not fit the typical clinical picture of hyperthyroidism presented by the patient's symptoms.
Question 7: A patient presents with symptoms of hyperthyroidism. Thyroid function tests would probably reveal:
- A. Increased T4, Increased T3, decreased TSH (Correct Answer)
- B. Increased T4, normal T3, and increased TSH
- C. Increased T3, T4, and increased TSH
- D. Decreased T3 and T4, increased TSH
Explanation: ***Increased T4, Increased T3, decreased TSH*** - In **primary hyperthyroidism**, the thyroid gland overproduces thyroid hormones (**T3 and T4**), leading to elevated levels [1]. - The high levels of T3 and T4 then **feedback negatively** on the pituitary gland, suppressing the release of **TSH** [1]. *Increased T4, normal T3, and increased TSH* - This pattern is inconsistent with primary hyperthyroidism, as elevated T3 and T4 should suppress TSH. - An isolated increase in T4 with normal T3 can occur in **subclinical hyperthyroidism** or **thyroxine (T4) resistance**, but increased TSH would suggest pituitary dysfunction or resistance to thyroid hormones. *Increased T3, T4, and increased TSH* - Elevated T3 and T4 accompanied by **increased TSH** is a rare presentation, usually indicating **TSH-secreting pituitary adenoma** (secondary hyperthyroidism) or **thyroid hormone resistance** [1], [2]. - In typical hyperthyroidism, high thyroid hormone levels would suppress TSH. *Decreased T3 and T4, increased TSH* - This profile is characteristic of **primary hypothyroidism**, where an underactive thyroid gland produces insufficient T3 and T4 [1]. - The low thyroid hormone levels stimulate the pituitary to release **more TSH** in an attempt to stimulate thyroid hormone production [1].
Question 8: A 65 year old female presents with a swelling in the neck diagnosed as a solitary thyroid nodule. The patient is investigated and a scan shows increased uptake of iodine. Serum T3 and T4 are elevated . Most probabe diagnosis is
- A. Benign Thyroid Nodule
- B. Solitary Toxic Adenoma (Correct Answer)
- C. Follicular Carcinoma
- D. Toxic Multinodular Goiter
Explanation: A **solitary toxic adenoma** is a single thyroid nodule that autonomously produces thyroid hormones, leading to **hyperthyroidism**. The increased iodine uptake on scan reflects its hyperfunctional state, and elevated **T3/T4** confirms hyperthyroidism. [2] - The combination of a **solitary nodule**, **increased iodine uptake**, and **elevated thyroid hormone levels** is pathognomonic for a solitary toxic adenoma. [2] *Benign Thyroid Nodule* - A **benign thyroid nodule** without hyperfunction would typically show **normal or decreased iodine uptake** and **normal T3/T4** levels. [2] - While benign, such a nodule alone does not explain the **elevated T3/T4** or **increased iodine uptake**. *Follicular Carcinoma* - **Follicular carcinoma** is a type of thyroid cancer that typically presents as a **cold nodule** (decreased iodine uptake) and is usually **non-functional**, meaning it does not cause hyperthyroidism with elevated T3/T4. [2] - The presence of **increased iodine uptake** and **hyperthyroidism** makes follicular carcinoma highly unlikely. *Toxic Multinodular Goiter* - A **toxic multinodular goiter** involves **multiple nodules**, not a solitary one, that are autonomously functional and cause hyperthyroidism. [1] - While it causes **hyperthyroidism** and **increased iodine uptake**, the key differentiating factor here is the presentation as a **solitary nodule**.
Question 9: A patient presents with headaches, palpitations, hypertension, and urine VMA positivity. The biopsy findings are shown in the image. Which of the following statements is correct?
- A. Mostly malignant
- B. Mostly in children
- C. Mostly bilateral
- D. Associated with MEN 2A (Correct Answer)
Explanation: ***Associated with MEN 2A*** - The clinical presentation (headaches, palpitations, hypertension) and positive **urine VMA (vanillylmandelic acid)** strongly suggest a **pheochromocytoma**. - Pheochromocytomas are tumors of the adrenal medulla that secrete catecholamines and are frequently associated with **Multiple Endocrine Neoplasia Type 2A (MEN 2A)**, along with medullary thyroid carcinoma and primary hyperparathyroidism. *Mostly malignant* - Pheochromocytomas are generally benign, with approximately **10% being malignant** ("rule of 10s"). - Malignancy is difficult to predict based on histology alone and is usually defined by the presence of **metastases**. *Mostly in children* - While pheochromocytomas can occur at any age, they are **more common in adults**, typically between 30 and 50 years old. - When they do occur in children, they are more often bilateral, extra-adrenal, or associated with genetic syndromes. *Mostly bilateral* - The majority of pheochromocytomas (approximately **90%**) are **unilateral**. - Bilateral pheochromocytomas are often seen in genetic syndromes such as **MEN 2**, von Hippel-Lindau disease, and neurofibromatosis type 1.
Question 10: Preoperative medication of thyrotoxicosis are all except?
- A. Carbimazole
- B. PTU
- C. Propranolol
- D. Levothyroxine (Correct Answer)
Explanation: Levothyroxine - Levothyroxine is a synthetic thyroid hormone used to treat hypothyroidism, meaning it increases thyroid hormone levels, which would worsen thyrotoxicosis [1]. - Its administration would be contraindicated in a patient with thyrotoxicosis, as the goal is to reduce thyroid hormone levels preoperatively. Carbimazole - Carbimazole is a thionamide drug that inhibits the synthesis of thyroid hormones, making it a critical medication for treating hyperthyroidism and preparing patients for surgery [1]. - It reduces the amount of thyroid hormone produced by the thyroid gland, thus mitigating the risks associated with thyrotoxicosis during surgery. PTU - Propylthiouracil (PTU), like carbimazole, is a thionamide that blocks thyroid hormone synthesis and also inhibits the conversion of T4 to T3 [1]. - It is used in the preoperative management of thyrotoxicosis to achieve a euthyroid state and prevent a thyroid storm. Propranolol - Propranolol is a beta-blocker used to manage the symptoms of thyrotoxicosis, particularly the cardiovascular effects such as tachycardia, palpitations, and tremors [1]. - While it does not affect thyroid hormone levels directly, it helps control symptoms and stabilize the patient preoperatively, making them a safer candidate for surgery [1].
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