Endocrinology — MCQs

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 1591: Which of the following glands is NOT typically involved in Multiple Endocrine Neoplasia type II A (MEN II A)?

A. Pituitary gland (Correct Answer)
B. Thyroid gland
C. Parathyroid gland
D. Adrenal gland

Explanation: ***Pituitary gland*** - The **pituitary gland** is not a characteristic component of **MEN II A**. It is, however, associated with **Multiple Endocrine Neoplasia type I (MEN I)**, which involves the 3 Ps: **pituitary**, **parathyroid**, and **pancreas** [1]. - **MEN IIA** classically involves **medullary thyroid carcinoma**, **pheochromocytoma**, and **parathyroid hyperplasia** [1]. *Thyroid gland* - The **thyroid gland** is centrally involved in MEN IIA, specifically through the development of **medullary thyroid carcinoma (MTC)**, a hallmark feature. - MTC arises from the parafollicular C cells of the thyroid and secretes **calcitonin**. *Parathyroid gland* - The **parathyroid gland** is often involved in MEN IIA, typically presenting as **parathyroid hyperplasia** or adenoma, leading to **primary hyperparathyroidism**. - This typically results in elevated **parathyroid hormone** levels and **hypercalcemia**. *Adrenal gland* - The **adrenal gland** is a key player in MEN IIA due to the occurrence of **pheochromocytoma**, a tumor of the adrenal medulla. - Pheochromocytomas can be bilateral and secrete **catecholamines**, leading to hypertension and other symptoms.

Question 1592: Which of the following statements about hypercalcemia in sarcoidosis is false?

A. PTHrP level is increased
B. Parathormone level is increased (Correct Answer)
C. Oral steroids are useful
D. Calcitriol level is increased

Explanation: ***Parathormone level is increased*** - In **sarcoidosis-associated hypercalcemia**, the parathormone (PTH) level is typically **low or suppressed**. [1] - This is because the hypercalcemia is due to **extra-renal 1-$\alpha$ hydroxylation** of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D (calcitriol) by macrophages in granulomas, not primary hyperparathyroidism. [1] *PTHrP level is increased* - This statement is **false** for sarcoidosis. Elevated **parathyroid hormone-related peptide (PTHrP)** is a common cause of hypercalcemia in **malignancy**, particularly squamous cell carcinomas, but not in sarcoidosis. - Hypercalcemia in sarcoidosis is **PTH-independent** and not mediated by PTHrP. [1] *Oral steroids are useful* - This statement is **true**. **Corticosteroids** (like oral prednisone) are effective in treating hypercalcemia in sarcoidosis. - They work by **inhibiting the activity of 1-$\alpha$ hydroxylase** in alveolar macrophages and reducing intestinal calcium absorption. *Calcitriol level is increased* - This statement is **true**. In sarcoidosis, activated **macrophages within granulomas** aberrantly express **1-$\alpha$ hydroxylase**. [1] - This leads to the **extra-renal synthesis of calcitriol** (1,25-dihydroxyvitamin D), which increases intestinal calcium absorption and bone resorption, causing hypercalcemia. [1]

Question 1593: Primary hypercholesterolemia is:

A. Type I
B. Type IIb
C. Type IIa (Correct Answer)
D. Type III

Explanation: ***Type Ha*** - **Primary hypercholesterolemia** specifically refers to **Familial Hypercholesterolemia**, which is classified as Type Ha due to a genetic defect affecting LDL receptor activity [1]. - It typically presents with **high cholesterol levels** and an increased risk of premature cardiovascular disease [1]. *Type I* - Type I hyperlipoproteinemia is associated with **chylomicronemia**, leading to elevated triglycerides rather than cholesterol. - Symptoms include **pancreatitis** and eruptive xanthomas, not primarily high cholesterol levels. *Type III* - Type III hyperlipoproteinemia is known as **Dysbetalipoproteinemia**, associated with **increased IDL** and can cause elevated cholesterol, but is not classified as primary hypercholesterolemia. - It typically presents with **tuberous xanthomas** and is linked to **apolipoprotein E deficiency**. *Type IIb* - Type IIb hyperlipoproteinemia involves **elevation of LDL and VLDL**, but it is not classified as primary hypercholesterolemia; it is a mixed dyslipidemia. - This type usually features **increased cholesterol** and **triglycerides**, distinguishing it from the familial form classified as Type Ha.

Question 1594: Chronic atrophy of adrenal gland will result in which hormone deficiency ?

A. Aldosterone
B. Dehydroepiandrosterone (DHEA)
C. Epinephrine
D. Cortisol (Correct Answer)

Explanation: ***Cortisol*** - **Chronic atrophy of the adrenal gland**, often seen in conditions like **Addison's disease** [1], primarily leads to a deficiency of **glucocorticoids**, the main one being cortisol [2]. - **Cortisol** is produced in the **zona fasciculata** of the adrenal cortex, which is highly susceptible to damage in atrophic conditions [2]. *Aldosterone* - While aldosterone is produced in the adrenal cortex (**zona glomerulosa**), its deficiency is more characteristic of primary adrenal insufficiency affecting the entire cortex, not necessarily solely from 'chronic atrophy' which can have varied pathophysiology [2]. - In some autoimmune forms of adrenal atrophy (Addison's disease), **aldosterone deficiency** can occur, but **cortisol deficiency** is a more universal and defining feature [1][3]. *Dehydroepiandrosterone (DHEA)* - **DHEA** is an adrenal androgen produced in the **zona reticularis** of the adrenal cortex [2]. Its deficiency is also common in adrenal atrophy. - However, **cortisol deficiency** generally has more immediate and life-threatening clinical consequences compared to DHEA deficiency. *Epinephrine* - Epinephrine is produced by the **adrenal medulla**, which is distinct from the adrenal cortex where atrophy typically occurs in conditions causing hormone deficiencies. - Therefore, **adrenal gland atrophy** primarily affecting the cortex would not lead to **epinephrine deficiency** as the medulla usually remains functional.

Question 1595: Primary hyperparathyroidism is suggested by all of the following, except which of the following?

A. Increased serum calcium
B. Low urinary calcium levels (Correct Answer)
C. Increased urinary calcium
D. Decreased PTH levels

Explanation: ***Low urinary calcium*** - In primary hyperparathyroidism, **urinary calcium levels are typically elevated** due to increased calcium reabsorption in the kidneys [2]. - **Low urinary calcium levels** would suggest a different condition, such as **hypoparathyroidism** or a renal issue affecting calcium excretion [5]. *Increased PTH* - Primary hyperparathyroidism is characterized by **elevated parathyroid hormone (PTH)** levels, as the parathyroid glands are overactive [1][3]. - High PTH contributes to increased serum calcium and bone resorption [2]. *Increased serum calcium* - A hallmark of primary hyperparathyroidism is **hypercalcemia**, resulting from increased bone resorption and renal tubular reabsorption of calcium [1][2]. - The condition often leads to symptoms such as **kidney stones** and **bone pain** due to elevated serum calcium levels [3][4]. *Increased C-AMP* - Elevated levels of **cyclic AMP (C-AMP)** in urine are observed in primary hyperparathyroidism due to the stimulatory effect of PTH on renal tubular reabsorption of calcium. - Increased C-AMP correlates with the action of PTH in promoting calcium release from the bones [2].

Question 1596: Hypophosphatemia is seen in:

A. Hyperthyroidism
B. Hypoparathyroidism
C. Hyperparathyroidism (Correct Answer)
D. Pseudohypoparathyroidism

Explanation: ***Hyperparathyroidism*** - In **primary hyperparathyroidism**, the excess **parathyroid hormone (PTH)** leads to increased phosphate excretion by the kidneys [1], [4]. - This results in **hypophosphatemia** as the body attempts to maintain **calcium-phosphate balance**, often at the expense of phosphate levels [1]. *Hyperthyroidism* - While hyperthyroidism can affect **bone metabolism**, it is typically associated with **normal or slightly elevated phosphate levels**, not hypophosphatemia [3]. - The main electrolyte disturbances are usually related to **calcium** (e.g., hypercalcemia) due to increased bone turnover [3]. *Hypoparathyroidism* - **Hypoparathyroidism** is characterized by **low or absent PTH**, leading to decreased renal phosphate excretion. - This results in **hyperphosphatemia**, along with **hypocalcemia** [2]. *Pseudohypoparathyroidism* - In **pseudohypoparathyroidism**, there is **PTH resistance** at target tissues, even with high or normal PTH levels [2]. - This leads to symptoms resembling hypoparathyroidism, including **hyperphosphatemia** and **hypocalcemia** [2].

Question 1597: What is a significant cause of male pseudohermaphroditism?

A. Adrenocortical tumor
B. Cytogenetic abnormalities
C. Androgen insensitivity syndrome (Correct Answer)
D. Congenital adrenal hyperplasia (CAH)

Explanation: ***Cytogenetic abnormalities*** - Male pseudohermaphroditism is most commonly caused by **isolated androgen insensitivity syndrome**, resulting from **androgen receptor gene mutations** [3]. - It leads to **male chromosomal composition (46,XY)** but with female phenotype due to lack of response to male hormones [3]. *Chromosomal abnormalities* - While chromosomal abnormalities can lead to **disorders of sexual development**, they are not the primary cause of pseudohermaphroditism [2], [3]. - Conditions like **Turner syndrome** affect development primarily in female individuals [1]. *Congenital adrenal hyperplasia* - More commonly leads to **female pseudohermaphroditism** due to excess androgen exposure during fetal life [3]. - In male infants, it typically presents as **salt-wasting**, affecting the adrenal glands rather than causing male pseudohermaphroditism [3]. *Adrenocortical tumor* - This condition can cause excess secretion of adrenal hormones, potentially leading to **precocious puberty**, but it does not typically cause pseudohermaphroditism. - It primarily affects adrenal function rather than sexual differentiation at the chromosomal level.

Question 1598: What is the most characteristic symptom of pheochromocytoma?

A. Episodic hypertension (Correct Answer)
B. Headaches
C. Rapid heart rate
D. Anxiety attacks

Explanation: ***Episodic hypertension*** - This is the **most characteristic and consistent symptom**, occurring in nearly all patients [1]. It is caused by unpredictable surges in **catecholamine** release. - The hypertension can be paroxysmal (episodic) or sustained [1], but the episodic nature is a key diagnostic clue. *Headaches* - **Headaches** are a common symptom but are less specific to pheochromocytoma, as they can be caused by many conditions. - While headaches in pheochromocytoma can be severe and throbbing, they are an indirect result of the **hypertensive crisis**, not the primary defining feature. *Rapid heart rate* - **Tachycardia** (rapid heart rate) is a frequent manifestation due to **catecholamine** excess. - However, it often accompanies the hypertensive episodes and is not as universally characteristic or diagnostic as the **episodic hypertension** itself [1]. *Anxiety attacks* - Patients can experience symptoms mimicking **anxiety or panic attacks**, including profound apprehension, palpitations, and sweating. - While these can be prominent, they are typically secondary to the physiological effects of **catecholamine** surge and the resulting intense physical sensations, rather than the core diagnostic feature.

Question 1599: A pregnant woman is diagnosed with Graves' disease. The most appropriate therapy for her would be:

A. Radioiodine therapy
B. Total thyroidectomy
C. Carbimazole parenteral
D. Propylthiouracil oral (Correct Answer)

Explanation: ***Propylthiouracil oral*** - **Propylthiouracil (PTU)** is the preferred antithyroid drug during the **first trimester** of pregnancy due to a lower risk of teratogenicity compared to methimazole/carbimazole [1]. - It works by inhibiting both the synthesis of thyroid hormones and the peripheral conversion of **T4 to T3**. *Radioiodine therapy* - **Radioactive iodine** is absolutely contraindicated in pregnancy as it can cross the placenta and cause **fetal hypothyroidism or athyreosis**. - It leads to permanent destruction of the thyroid gland and is not suitable for a temporary condition in a pregnant woman. *Total thyroidectomy* - While thyroidectomy can be considered for Graves' disease in pregnancy, it is generally reserved for cases where antithyroid drugs are not tolerated or ineffective, or for very large goiters causing compressive symptoms. - It carries risks associated with **surgery and anesthesia** during pregnancy, and requires **lifelong thyroid hormone replacement**. *Carbimazole parenteral* - **Carbimazole** (which is metabolized to methimazole) is generally avoided in the **first trimester** due to an increased risk of teratogenicity, particularly **aplasia cutis**, omphalocele, and choanal atresia [1]. - While it can be used in the second and third trimesters, **PTU is preferred in the first trimester**, and carbimazole is not typically administered parenterally.

Question 1600: Investigation of choice in pheochromocytoma is:

A. CT scan
B. Urinary catecholamines (Correct Answer)
C. MIBG scan
D. MRI Scan

Explanation: ***Urinary catecholamines*** - Measurement of **24-hour urinary fractionated metanephrines and catecholamines** is the initial **biochemical test of choice**. - These biochemical tests are preferred over plasma levels due to the **episodic release** of hormones from a pheochromocytoma, which can lead to high false-negative rates in single plasma measurements. *CT scan* - While a **CT scan** is a crucial **imaging modality** for localizing a pheochromocytoma once the biochemical diagnosis is established [1], it is not the *initial* diagnostic investigation. - Imaging should be performed only after **biochemical confirmation** to avoid unnecessary investigations of incidental adrenal masses [1]. *MIBG scan* - An **MIBG scan** (metaiodobenzylguanidine scan) is a **functional imaging study** used primarily for **localizing metastatic pheochromocytomas** [1] or for cases where CT/MRI is equivocal. - It is not the initial investigation but rather a **secondary imaging test** [1]. *MRI Scan* - **MRI** is an alternative **imaging modality** to CT for localizing pheochromocytomas [1], especially in pregnant women or when radiation exposure is a concern. - Like CT, it serves as a **localization tool** after biochemical confirmation, not the diagnostic test itself.

Practice by Chapter

Diabetes Mellitus

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Thyroid Disorders

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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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