Endocrinology — MCQs

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 1691: A hypertensive patient who is a chronic smoker presented with recurrent hemoptysis, and on examination, he had cushingoid features. Investigations revealed raised ACTH levels that were not suppressed by dexamethasone. The single diagnosis that can account for all his symptoms is

A. Adrenocortical adenoma
B. Ectopic ACTH-producing tumor (Correct Answer)
C. Multiple endocrine neoplasia type I
D. Cushing's disease due to pituitary adenoma

Explanation: ***Ectopic ACTH-producing tumor*** - The combination of **Cushingoid features**, **recurrent hemoptysis** (suggesting a lung tumor), **hypertension**, elevated **ACTH levels**, and non-suppressibility by **dexamethasone** strongly points to an **ectopic ACTH-producing tumor**, most commonly a small cell lung carcinoma [1], [2]. - The patient's **chronic smoking history** further increases the likelihood of a paraneoplastic syndrome associated with lung cancer. *Multiple endocrine neoplasia type I* - MEN 1 involves tumors of the parathyroid glands, pituitary gland, and pancreas, leading to symptoms like **hypercalcemia**, **acromegaly**, or **Zollinger-Ellison syndrome**. - While pituitary tumors can cause Cushing's disease, the **hemoptysis** and **chronic smoking history** are not typical features of MEN 1. *Adrenocortical adenoma* - An **adrenocortical adenoma** would cause **Cushing's syndrome** due to primary adrenal cortisol overproduction, leading to **suppressed ACTH levels** rather than elevated levels [1], [2]. - It would not explain the **hemoptysis** or the non-suppressibility of ACTH by dexamethasone. *Cushing's disease due to pituitary adenoma* - **Cushing's disease** is caused by a **pituitary adenoma** secreting ACTH, leading to elevated ACTH and cortisol levels [1]. - While it causes **Cushingoid features** and **hypertension**, it would typically show partial suppression of **ACTH** with high-dose dexamethasone and does not explain the **hemoptysis**.

Question 1692: Most common cause of Cushing's syndrome is what?

A. Adrenal adenoma
B. Adrenal carcinoma
C. McCune Albright syndrome
D. Pituitary adenoma (Correct Answer)

Explanation: ***Pituitary adenoma*** - The **most common cause** of Cushing's syndrome, specifically **Cushing's disease**, is excess ACTH production from a pituitary adenoma [1]. - This leads to **overstimulation of the adrenal glands**, resulting in increased cortisol production [1]. *McCune Albright syndrome* - It is a genetic disorder characterized by **fibrous dysplasia**, **café-au-lait spots**, and **endocrine problems**, not primarily Cushing's syndrome. - Though hormone abnormalities may present, it is not the **most common** cause of Cushing's syndrome. *Adrenal carcinoma* - While adrenal carcinoma can cause **Cushing's syndrome**, it is less common compared to the **pituitary adenoma** [1]. - This malignant tumor is rare and typically presents with more aggressive features and higher cortisol levels. *Adrenal adenoma* - Adrenal adenomas are benign tumors that can produce **excess cortisol**, but they are not the leading cause of Cushing's syndrome overall [1]. - They account for a smaller proportion of cases compared to **pituitary adenomas**.

Question 1693: Hypercalcemia is not a feature of which one of the following conditions?

A. Primary hyperparathyroidism
B. Multiple myeloma
C. Sarcoidosis
D. Tumor lysis syndrome (Correct Answer)

Explanation: Tumor lysis syndrome is characterized by the rapid breakdown of tumor cells, leading to the release of intracellular contents. This typically causes **hyperkalemia**, **hyperphosphatemia**, and **hyperuricemia**, but generally **hypocalcemia** due to phosphate binding [3], not hypercalcemia. *Primary hyperparathyroidism* - This condition involves excessive production of **parathyroid hormone (PTH)**, which leads to increased bone resorption, increased renal calcium reabsorption, and increased vitamin D activation, all contributing to **hypercalcemia** [1], [4]. - It is a common cause of isolated elevated calcium levels, often discovered incidentally [2]. *Multiple myeloma* - Multiple myeloma is a plasma cell malignancy that causes extensive **bone destruction** through the release of osteoclast-activating factors. - This increased bone resorption leads to a significant release of calcium into the bloodstream, resulting in **hypercalcemia** [1]. *Sarcoidosis* - Sarcoidosis is a granulomatous disease where activated macrophages in the granulomas produce **1,25-dihydroxyvitamin D** (calcitriol). - This excess calcitriol leads to increased intestinal absorption of calcium and increased bone resorption, causing **hypercalcemia** [1].

Question 1694: Which of the following conditions is least likely to cause weight loss?

A. Pheochromocytoma
B. Adrenal insufficiency
C. Uremia
D. Insulinoma (Correct Answer)

Explanation: ***Insulinoma*** - An **insulinoma** is a tumor of the pancreatic beta cells that secretes excessive insulin, leading to **hypoglycemia**. - While patients may experience weight gain due to frequent eating to counteract hypoglycemic episodes, significant weight loss is **uncommon** and not a primary feature [1]. *Pheochromocytoma* - **Pheochromocytoma** is a tumor that secretes high levels of **catecholamines** (epinephrine and norepinephrine), which increase metabolic rate. - This increased metabolism often leads to significant **weight loss**, along with symptoms like hypertension, palpitations, and sweating. *Adrenal insufficiency* - **Adrenal insufficiency** (Addison's disease) is characterized by decreased production of cortisol and aldosterone, leading to chronic GI symptoms, weakness, and **anorexia**. - Patients often experience **unexplained weight loss** due to nausea, vomiting, and loss of appetite. *Uremia* - **Uremia** refers to the accumulation of urea and other nitrogenous waste products in the blood, typically seen in advanced **kidney failure**. - It often causes symptoms like **anorexia**, nausea, vomiting, and a metallic taste in the mouth, all of which contribute to significant **weight loss**.

Question 1695: ACTH reserve is best assessed by which test?

A. Insulin-induced hypoglycemia (Correct Answer)
B. Corticotropin-releasing hormone (CRH) test
C. ACTH stimulation test
D. Glucocorticoid levels assessment

Explanation: ***Insulin-induced hypoglycemia*** - This test is considered the **gold standard** for assessing ACTH reserve because the resulting **severe stress** is the most potent physiological stimulus for both ACTH and growth hormone secretion [1]. - A healthy pituitary gland will respond to the stress of hypoglycemia by significantly increasing ACTH and cortisol levels; a blunted response indicates **adrenal insufficiency** or **pituitary dysfunction** [1]. *Corticotropin-releasing hormone (CRH) test* - The CRH test assesses the **pituitary's response to CRH** in releasing ACTH, helping to distinguish between primary and secondary adrenal insufficiency. - While it evaluates ACTH secretion, it does not assess the overall functional reserve of the HPA axis to a strong physiological stressor as effectively as insulin-induced hypoglycemia. *ACTH stimulation test* - The ACTH stimulation test, or **cosyntropin stimulation test**, directly evaluates the **adrenal gland's capacity to produce cortisol** in response to exogenous ACTH [2]. - This test assesses primary adrenal insufficiency, but it does not evaluate the **pituitary gland's ability to release ACTH** (ACTH reserve) [2]. *Glucocorticoid levels assessment* - Measuring baseline glucocorticoid (cortisol) levels provides a snapshot of adrenal function at a single point in time, but it does not assess the **reserve or responsiveness of the HPA axis** to stress [1]. - For a more accurate assessment, these levels need to be interpreted in the context of diurnal variation or dynamic testing [1].

Question 1696: As per the etiological classification of diabetes mellitus, gestational diabetes mellitus is

A. Type IA
B. Type IB
C. Type II
D. Type IV (Correct Answer)

Explanation: ***Type IV*** - According to the **etiological classification of diabetes mellitus**, gestational diabetes mellitus (GDM) is classified as **Type IV** [1]. - GDM is specifically defined as **diabetes diagnosed during pregnancy** that is not clearly overt diabetes prior to gestation [2]. *Type IA* - Type IA diabetes refers to **autoimmune Type 1 Diabetes**, characterized by immune-mediated destruction of pancreatic beta cells [1]. - This form of diabetes typically presents in childhood or adolescence and is associated with **autoantibodies** against islet cells. *Type IB* - Type IB diabetes refers to **idiopathic Type 1 Diabetes**, which is a form of Type 1 diabetes where there is no evidence of autoimmunity [1]. - It is rare and primarily seen in individuals of African or Asian descent, distinguished by a lack of **autoimmune markers**. *Type II* - Type II diabetes is characterized by **insulin resistance** and a progressive loss of insulin secretion, typically diagnosed in adults. - While GDM shares some physiological characteristics with Type II diabetes, it is a distinct *classification* due to its onset specific to **pregnancy** [2].

Question 1697: Which antibodies are primarily associated with Graves' disease?

A. TSH receptor antibodies (TRAb) (Correct Answer)
B. Antinuclear antibodies (ANA)
C. Thyroid peroxidase antibodies (TPO)
D. Anti-thyroglobulin antibodies

Explanation: ***TSH receptor antibodies (TRAb)*** - **TRAb** directly stimulate the **TSH receptor** on thyroid follicular cells, leading to excessive thyroid hormone production and the characteristic features of **Graves' disease** [1], [2]. - These antibodies are highly specific for Graves' disease and are used for diagnosis, management, and prediction of remission [1]. *Antinuclear antibodies (ANA)* - **ANA** are associated with various **systemic autoimmune diseases** like lupus and scleroderma, not primarily with Graves' disease. - While ANA can be positive in a small percentage of Graves' patients due to general immune dysregulation, they are not the causative or primary diagnostic antibody. *Thyroid peroxidase antibodies (TPO)* - **TPO antibodies** are primarily associated with **Hashimoto's thyroiditis**, causing thyroid destruction and hypothyroidism. - Although they can be present in Graves' disease, they are not the main pathogenic antibodies responsible for hyperthyroidism. *Anti-thyroglobulin antibodies* - **Anti-thyroglobulin antibodies** are also mainly associated with **Hashimoto's thyroiditis** and other autoimmune thyroid conditions. - They target thyroglobulin, a precursor to thyroid hormones, but do not directly stimulate thyroid hormone synthesis as TRAb do in Graves' disease.

Question 1698: Which assay is primarily used to assess growth hormone levels?

A. Diabetes mellitus
B. Glucagon assay
C. Growth hormone stimulation test (Correct Answer)
D. Catecholamines

Explanation: ***Growth hormone stimulation test*** - This is the primary diagnostic assay to evaluate **growth hormone (GH) deficiency** or excess, as GH levels fluctuate throughout the day. - Various stimuli, such as **insulin-induced hypoglycemia**, **arginine**, or **clonidine**, are used to trigger GH release, and levels are measured serially [1]. *Diabetes mellitus* - This is a metabolic disorder characterized by **elevated blood glucose levels** due to insulin deficiency or resistance, not an assay for growth hormone. - While growth hormone can affect glucose metabolism, diabetes mellitus describes a **disease state**, not a diagnostic test for growth hormone levels [2]. *Glucagon assay* - A glucagon assay measures the level of **glucagon**, a hormone produced by the pancreas that raises blood glucose levels. - While glucagon can be used in some stimulation tests for growth hormone, a "glucagon assay" alone is not the primary method to assess overall growth hormone status. *Catecholamines* - Catecholamines are a group of hormones, including **epinephrine (adrenaline)**, **norepinephrine**, and **dopamine**, which are involved in the body's stress response. - Assays for catecholamines are used to diagnose conditions like **pheochromocytoma** or neuroblastoma, not to assess growth hormone levels.

Question 1699: Which of the following statements is true regarding testicular feminization syndrome (androgen insensitivity syndrome)? a) Testes are present, b) Female habitus, c) XY genotype, d) Uterus present.

A. Female phenotype with XY genotype.
B. Testes are present and XY genotype.
C. Presence of uterus and XY genotype.
D. Presence of testes, female phenotype, and XY genotype. (Correct Answer)

Explanation: ***Presence of testes, female phenotype, and XY genotype.*** - Testicular feminization syndrome, or **androgen insensitivity syndrome (AIS)**, is characterized by an **XY genotype** (chromosomal male) with a **female phenotype** due to the body's inability to respond to androgens. - Individuals with AIS possess **testes**, which produce androgens, but the target cells lack functional androgen receptors, leading to feminization. *Testes are present and XY genotype.* - While correct that **testes are present** and the genotype is **XY**, this option is incomplete as it doesn't mention the striking feature of the female phenotype. - The core of the syndrome is the discrepancy between the genetic sex and the external appearance, which is not fully captured. *Female phenotype with XY genotype.* - This statement is accurate regarding the **phenotype** and **genotype** but omits the presence of internal gonads (testes), which is a key diagnostic feature. - The presence of female external characteristics despite a male genotype is central to the diagnosis and understanding of AIS. *Presence of uterus and XY genotype.* - This statement is incorrect because individuals with complete androgen insensitivity syndrome **do not have a uterus**. - The **Müllerian inhibiting factor** produced by the testes during fetal development causes the regression of Müllerian ducts, preventing uterus formation.

Question 1700: A patient with hypertension presents with hypokalemia. Aldosterone levels and renin levels are both elevated. The most likely diagnosis is.

A. Primary Hyperaldosteronism {Conn's syndrome}
B. Addison's disease
C. Cushing's syndrome
D. Renal Artery stenosis (Correct Answer)

Explanation: ***Renal Artery stenosis*** - **Renal artery stenosis** leads to decreased renal perfusion, activating the **renin-angiotensin-aldosterone system (RAAS)** [2]. - This results in elevated **renin** and subsequent elevated **aldosterone** levels, causing hypertension and **hypokalemia** [3]. *Primary Hyperaldosteronism (Conn's syndrome)* - In **primary hyperaldosteronism**, the adrenal glands autonomously overproduce **aldosterone**, leading to high aldosterone levels [1]. - The high aldosterone levels suppress **renin** secretion, resulting in low renin levels, which contradicts the patient's presentation. *Addison's disease* - **Addison's disease** (primary adrenal insufficiency) is characterized by decreased production of all adrenal hormones, including **aldosterone** and **cortisol**. - This would lead to **hyponatremia**, **hyperkalemia**, and low blood pressure, not hypokalemia and hypertension. *Cushing's syndrome* - **Cushing's syndrome** results from excessive **cortisol** production, which can have mineralocorticoid effects and cause hypertension and hypokalemia. - However, **cortisol** excess does not directly cause elevated **renin** levels; renin is typically normal or suppressed in Cushing's.

Practice by Chapter

Diabetes Mellitus

Practice Questions

Thyroid Disorders

Practice Questions

Adrenal Gland Disorders

Practice Questions

Pituitary Disorders

Practice Questions

Calcium and Bone Metabolism

Practice Questions

Reproductive Endocrinology

Practice Questions

Lipid Disorders

Practice Questions

Endocrine Hypertension

Practice Questions

Multiple Endocrine Neoplasia

Practice Questions

Obesity and Metabolic Syndrome

Practice Questions

Neuroendocrine Tumors

Practice Questions

Endocrine Emergencies

Practice Questions

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