Endocrinology — MCQs

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 1581: 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 1582: Which type of thyroid cancer is associated with primary hyperparathyroidism and phaeochromocytoma?

A. Medullary carcinoma of the thyroid (Correct Answer)
B. Papillary carcinoma of the thyroid
C. Anaplastic carcinoma of the thyroid
D. Follicular carcinoma of the thyroid

Explanation: ***Medullary carcinoma of the thyroid*** - Associated with **multiple endocrine neoplasia (MEN) syndrome type 2**, which includes primary hyperparathyroidism and phaeochromocytoma [1]. - Medullary carcinoma arises from **C cells** (parafollicular cells) and is linked with **elevated calcitonin** levels. *Papillary carcinoma of the thyroid* - The most common type of thyroid cancer, but **not associated** with MEN syndromes. - Typically presents as a solitary **nodule** and is linked with **radiation exposure** rather than endocrine syndromes. *Anaplastic carcinoma of the thyroid* - A highly aggressive and undifferentiated form of thyroid cancer, often associated with **poor prognosis**. - Usually arises in older adults and does not have associations with **hyperparathyroidism** or phaeochromocytoma. *Follicular carcinoma of the thyroid* - Characterized by **thyroid follicle formation** and can be associated with **iodine deficiency**, but not with MEN syndromes. - It usually presents as a **solitary thyroid nodule** and lacks connection with **primary hyperparathyroidism**.

Question 1583: A female patient presents with hirsutism, amenorrhea, and obesity. What is the most likely diagnosis?

A. Androgen-secreting ovarian tumor
B. Congenital adrenal hyperplasia
C. Cushing's syndrome
D. Polycystic Ovary Syndrome (PCOS) (Correct Answer)

Explanation: ***Polycystic Ovary Syndrome (PCOS)*** - **Hirsutism**, **amenorrhea** (or oligomenorrhea), and **obesity** are classic clinical features of PCOS, reflecting hyperandrogenism and insulin resistance [2]. - PCOS is a diagnosis of exclusion and involves chronic anovulation and polycystic ovaries on ultrasound [3], though these are not explicitly mentioned, the constellation of symptoms strongly points to it. *Androgen-secreting ovarian tumor* - While it can cause **hirsutism** and **amenorrhea**, the onset is typically **rapid** and severe, with very high androgen levels, and obesity is not a primary feature. - Ovarian tumors are generally less common than PCOS and may present with a palpable mass or specific imaging findings. *Congenital adrenal hyperplasia* - This genetic condition often presents in childhood or adolescence with varying degrees of **virilization** and menstrual irregularities due to enzyme deficiencies in cortisol synthesis [1]. - While it causes **hirsutism** and potentially **amenorrhea**, obesity is not a direct consequence, and the patient's age of presentation and specific symptom pattern are less typical for adult-onset CAH in this context. *Cushing's syndrome* - Characterized by **central obesity**, **moon facies**, **buffalo hump**, **striae**, and proximal muscle weakness due to chronic glucocorticoid excess. - Although it can cause **menstrual irregularities** and mild **hirsutism** [2], the overall clinical picture including the absence of other specific Cushingoid features makes it less likely than PCOS.

Question 1584: What condition is characterized by a short fourth metacarpal?

A. Primary Hyperparathyroidism
B. Secondary Hyperparathyroidism
C. Pseudohypoparathyroidism (Correct Answer)
D. Scleroderma

Explanation: Pseudohypoparathyroidism - **Pseudohypoparathyroidism** is characterized by end-organ resistance to parathyroid hormone (PTH), leading to hypocalcemia and hyperphosphatemia [2, 4]. - Patients often present with **Albright's hereditary osteodystrophy**, which includes characteristic features like a **shortened fourth metacarpal**, short stature, rounded face, and obesity [2, 4]. *Primary Hyperparathyroidism* - **Primary hyperparathyroidism** involves excessive PTH production from an adenoma or hyperplasia of the parathyroid glands [1, 3, 5]. - This typically leads to **hypercalcemia** and **hypophosphatemia**, and does not involve a short fourth metacarpal as a characteristic feature [1, 3, 5]. *Secondary Hyperparathyroidism* - **Secondary hyperparathyroidism** occurs as a compensatory response to hypocalcemia, often due to chronic kidney disease or vitamin D deficiency [1]. - It’s characterized by elevated PTH levels alongside the underlying cause of hypocalcemia, without the classic skeletal deformities seen in pseudohypoparathyroidism [1, 4]. *Scleroderma* - **Scleroderma** is a chronic autoimmune disease characterized by thickening and hardening of the skin and connective tissues. - It can lead to various complications like Raynaud phenomenon and internal organ fibrosis, but a **short fourth metacarpal is not a feature** of this condition.

Question 1585: Which of the following conditions is associated with male pseudohermaphroditism?

A. 21-hydroxylase deficiency
B. Androgen insensitivity syndrome
C. 17-hydroxylase deficiency
D. 5-alpha reductase deficiency (Correct Answer)

Explanation: ***5-alpha reductase deficiency*** - This deficiency prevents the conversion of **testosterone into dihydrotestosterone (DHT)**, which is essential for external male genitalia development. - Individuals with XY chromosomes are born with **ambiguous genitalia** that may appear female-like, leading to male pseudohermaphroditism. *21-hydroxylase deficiency* - This is the most common cause of **congenital adrenal hyperplasia (CAH)**, leading to overproduction of androgens. [1] - In XX individuals, it causes **virilization**, resulting in female pseudohermaphroditism, not male. [1] *17-hydroxylase deficiency* - This leads to impaired synthesis of **cortisol and sex steroids**, thus affecting adrenal and gonadal functions. [1] - XY individuals with this deficiency typically present with **female external genitalia** due to a lack of androgens, but it's a different mechanism than 5-alpha reductase deficiency. [1] *Androgen insensitivity syndrome* - In this condition, individuals with XY chromosomes have **non-functional androgen receptors**, making their bodies unable to respond to testosterone. [1] - They develop **female external genitalia** despite having testes and usually present as phenotypic females. [1]

Question 1586: A diabetic patient presents with sensory involvement, tingling, numbness, ankle swelling, and absence of pain. What is the most likely diagnosis?

A. Charcot's joint (Correct Answer)
B. Gout
C. Rheumatoid arthritis
D. Ankylosing spondylitis

Explanation: ***Charcot's joint*** - This condition is characterized by **neuropathic arthropathy**, resulting from nerve damage (often due to **diabetes**), leading to sensory involvement, **numbness**, and **absence of pain** [1]. - The loss of protective sensation and repeated microtrauma contribute to joint destruction, often manifesting as **swelling** and deformity, particularly in the feet and ankles [1]. *Gout* - Gout typically presents with sudden, severe episodes of **pain**, redness, and swelling in a single joint, most commonly the **big toe**. - It is caused by **uric acid crystal deposition** and is not primarily associated with sensory deficits or chronic painless swelling. *Rheumatoid arthritis* - This is a **chronic autoimmune** inflammatory disease primarily affecting the **small joints** of the hands and feet symmetrically, causing pain, stiffness, and swelling. - It does not typically present with sensory neuropathy or painless joint destruction in the way described. *Ankylosing spondylitis* - This is a **chronic inflammatory disease** primarily affecting the **spine and sacroiliac joints**, causing progressive stiffness and pain that improves with activity. - It is not associated with peripheral joint neuropathy, numbness, or painless ankle swelling [1].

Question 1587: Which of the following is not a treatment option for hypercalcemia?

A. Strontium (Correct Answer)
B. Bisphosphonates
C. Steroids
D. Phosphate

Explanation: ***Strontium*** - **Strontium ranelate** is primarily used in the treatment of **osteoporosis** to promote bone formation and inhibit bone resorption. - It does not have a recognized role in the acute or long-term management of **hypercalcemia** and could potentially worsen it due to its bone-targeting effects if not carefully managed. *Steroids* - **Glucocorticoids** are effective in treating hypercalcemia associated with **granulomatous diseases** (e.g., sarcoidosis) and certain malignancies (e.g., multiple myeloma) by reducing calcitriol production or tumor burden. - They decrease intestinal calcium absorption and increase renal calcium excretion in conditions where 1,25-dihydroxyvitamin D is elevated. *Bisphosphonates* - **Bisphosphonates** (e.g., zoledronic acid, pamidronate) are potent inhibitors of **osteoclast-mediated bone resorption** and are a cornerstone in the treatment of moderate to severe hypercalcemia, especially due to malignancy. [1] - They are administered intravenously and act by inducing osteoclast apoptosis, thereby reducing the release of calcium from bone. [1] *Phosphate* - **Intravenous phosphate** can be used in severe, resistant hypercalcemia, as it promotes calcium deposition into bone and soft tissues, and forms insoluble calcium-phosphate complexes, thus lowering serum calcium. - Its use is limited due to risks of **ectopic calcification**, renal failure, and hypotension, and it is usually reserved for life-threatening situations where other treatments have failed.

Question 1588: Adrenal reserve is best tested by means of infusion with

A. ACTH (Correct Answer)
B. Metyrapone
C. Corticosteroids
D. LHRH

Explanation: ACTH - The **ACTH stimulation test**, also known as the **cosyntropin test**, is the most common dynamic test for assessing adrenal reserve. - Exogenous ACTH (cosyntropin) stimulates the adrenal glands to produce cortisol; a subnormal response indicates adrenal insufficiency. *Corticosteroids* - **Corticosteroids** are hormones (like cortisol) produced by the adrenal glands, or synthetic versions used as medications; they do not test adrenal reserve but rather *replace* adrenal function. - Administering corticosteroids would interfere with, rather than assess, the adrenal gland's ability to produce its own hormones. *LHRH* - **Luteinizing hormone-releasing hormone (LHRH)** is used to assess the function of the anterior pituitary gland and gonads, not the adrenal glands. - An LHRH stimulation test evaluates the pituitary's ability to release LH and FSH, which in turn stimulate gonadal hormone production. *Metyrapone* - The **metyrapone test** assesses the integrity of the **hypothalamic-pituitary-adrenal axis** by blocking cortisol synthesis, which should lead to an increase in ACTH and 11-deoxycortisol [1]. - While it evaluates a part of adrenal function, it is primarily used to differentiate between primary and secondary adrenal insufficiency, and not a direct measure of cortisol production capacity in response to stimulation.

Question 1589: Which of the following is a common finding in patients with Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)?

A. Ascites
B. Normal BP (Correct Answer)
C. Generalized edema
D. Dry mucous membrane

Explanation: ***Normal BP*** - In SIADH, patients are typically **euvolemic** due to the primary issue being water retention rather than salt retention or frank dehydration [2]. - While hyponatremia occurs, the body's compensatory mechanisms usually prevent significant changes in blood pressure, maintaining it within the **normal range**. *Generalized edema* - Generalized edema is uncommon in SIADH because the excessive water retention is initially within the **intravascular compartment**, and the body attempts to excrete the additional volume of water [1]. - Although the patient is effectively retaining water, the osmolality is low, leading to fluid shifts rather than overt edema unless severe, protracted fluid overload occurs. *Ascites* - **Ascites**, which is the accumulation of fluid in the peritoneal cavity, is not a characteristic feature of SIADH [2]. - Ascites is more commonly associated with conditions like **liver cirrhosis**, heart failure, or malignancy. *Dry mucous membrane* - **Dry mucous membranes** are a sign of dehydration and fluid volume deficit. - In contrast, SIADH involves **fluid overload** (though euvolemic), making dry mucous membranes an unlikely finding [2].

Question 1590: Autoimmune thyroiditis is associated with all except which of the following?

A. DM
B. Myasthenia gravis
C. SLE
D. Psoriasis (Correct Answer)

Explanation: ***Psoriasis*** - Psoriasis is generally not associated with **autoimmune thyroiditis**, which is more commonly linked to other autoimmune disorders [1]. - Autoimmune thyroiditis does not typically result in the **skin changes** seen in psoriasis, distinguishing them clinically. *Sly* - Sly syndrome, while a genetic disorder, is not directly connected to **autoimmune thyroiditis**. - Conditions like Sly syndrome are metabolic and do not involve the autoimmune pathways typically seen in thyroiditis. *Myasthenia gravis* - Myasthenia gravis is an **autoimmune neuromuscular disorder** that can occur concurrently with thyroid diseases, particularly **thyroiditis** [1]. - Both conditions arise from **autoimmune processes**, making their association plausible [1]. *DM* - Diabetes Mellitus (DM), particularly Type 1, is often linked with other autoimmune diseases, including **autoimmune thyroiditis** [2]. - They share a common **autoimmune pathway**, making them more likely to co-occur than psoriasis [2].

Practice by Chapter

Diabetes Mellitus

Practice Questions

Thyroid Disorders

Practice Questions

Adrenal Gland Disorders

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Pituitary Disorders

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Calcium and Bone Metabolism

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Reproductive Endocrinology

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Lipid Disorders

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Endocrine Hypertension

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Multiple Endocrine Neoplasia

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Obesity and Metabolic Syndrome

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Neuroendocrine Tumors

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Endocrine Emergencies

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