Endocrinology — MCQs

An agitated, confused female client with a history of type 1 diabetes mellitus, hypertension, and angina pectoris presents to the emergency department with pallor, diaphoresis, headache, and intense hunger. A stat blood glucose sample measures 42 mg/dl, and the client is treated for an acute hypoglycemic reaction. After recovery, what should the nurse teach the client to ingest to treat hypoglycemia?

Q714Easy

All of the following conditions are known to cause diabetes insipidus except?

Q715Medium

A patient has IDDM diagnosed at age 15 years. What is the most reliable indicator for diabetic nephropathy?

Q716Easy

A short-statured boy with rhizomelic limbs and brachydactyly is a feature of which condition?

Q717Easy

Intravenous administration of two liters of normal saline over four hours will primarily stimulate the secretion of which hormone?

Q718Easy

What is the most common cause of hyperparathyroidism?

Q719Medium

A young patient presented with hypertension and a urinary VMA of 14 mg/24 hours. What is the most likely underlying cause?

Q720Medium

The occurrence of hyperthyroidism following administration of supplemental iodine to subjects with endemic iodine deficiency goiter is known as what?

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 711: Which of the following is a testosterone receptor antagonist?

A. Flutamide (Correct Answer)
B. Mifepristone
C. Danazol
D. Nonoxynol

Explanation: Explanation: Flutamide is the correct answer because it is a potent, non-steroidal competitive antagonist at the androgen receptor. By blocking the binding of dihydrotestosterone (DHT) and testosterone to their receptors in target tissues, it inhibits the growth-promoting effects of androgens. It is primarily used in the management of metastatic prostate cancer, often in combination with GnRH analogs to prevent the "testosterone flare." Analysis of Incorrect Options: * Mifepristone (RU-486): This is a progesterone and glucocorticoid receptor antagonist. It is clinically used for medical termination of pregnancy and the management of Cushing’s syndrome. * Danazol: This is a synthetic steroid with weak androgenic activity. It acts as a partial agonist at androgen receptors and suppresses the pituitary-ovarian axis by inhibiting mid-cycle LH and FSH surges. It is used in endometriosis and hereditary angioedema. * Nonoxynol-9: This is a spermicide (surfactant) used in topical contraceptives. It works by disrupting the cell membrane of spermatozoa; it has no hormonal receptor activity. High-Yield Clinical Pearls for NEET-PG: * Bicalutamide and Enzalutamide are newer, more potent androgen receptor blockers with better side-effect profiles than Flutamide. * Side Effect: A significant side effect of Flutamide is hepatotoxicity; liver enzymes must be monitored. It also causes gynecomastia due to increased peripheral conversion of accumulated testosterone to estrogen. * Finasteride vs. Flutamide: Do not confuse them. Finasteride is a 5-alpha reductase inhibitor (prevents conversion of T to DHT), whereas Flutamide blocks the receptor itself.

Question 712: Gynecomastia may be associated with which of the following conditions?

A. Klinefelter's syndrome
B. Feminizing tumor of the adrenal gland
C. Normal adolescent boys who are rapidly virilizing
D. All of the above (Correct Answer)

Explanation: Gynecomastia is the benign proliferation of glandular breast tissue in males, fundamentally caused by an **alteration in the estrogen-to-androgen ratio** (either increased estrogen or decreased androgen activity) [1]. **Breakdown of Options:** * **Klinefelter’s Syndrome (47, XXY):** This is the most common congenital cause of primary hypogonadism. Patients have small, firm testes and low testosterone levels [2]. The elevated LH levels stimulate the Leydig cells to aromatize testosterone into estradiol, leading to a high estrogen-to-androgen ratio and subsequent gynecomastia [2]. Men with Klinefelter syndrome are at a higher risk of breast tumors [3]. * **Feminizing Tumors of the Adrenal Gland:** These rare tumors (often carcinomas) directly secrete large amounts of estrogens or estrogen precursors (like androstenedione), which are peripherally converted to estrone and estradiol, leading to rapid feminization and gynecomastia. * **Normal Adolescent Boys (Physiologic):** Pubertal gynecomastia occurs in about 50–60% of boys [1]. It is caused by a transient imbalance where the rise in serum estradiol occurs earlier than the rise in testosterone during mid-puberty [1]. It is usually self-limiting and resolves within 1–2 years. **Clinical Pearls for NEET-PG:** 1. **Drugs causing Gynecomastia (High Yield):** Remember the mnemonic **"DISCO"** – **D**igitalis, **I**soniazid, **S**pironolactone (most common drug cause), **C**imetidine/Ketoconazole, **O**estrogens. 2. **Grading:** The Simon scale is used to grade gynecomastia (Grade I to III). 3. **Differential:** Always distinguish from **Pseudogynecomastia**, which is fatty tissue deposition without glandular proliferation, commonly seen in obese males [1]. 4. **Workup:** If a testicular mass is present, check markers like **β-hCG** (secreted by germ cell tumors), which can induce gynecomastia by stimulating LH receptors [1].

Question 713: An agitated, confused female client with a history of type 1 diabetes mellitus, hypertension, and angina pectoris presents to the emergency department with pallor, diaphoresis, headache, and intense hunger. A stat blood glucose sample measures 42 mg/dl, and the client is treated for an acute hypoglycemic reaction. After recovery, what should the nurse teach the client to ingest to treat hypoglycemia?

A. 2 to 5 g of a simple carbohydrate
B. 10 to 15 g of a simple carbohydrate (Correct Answer)
C. 18 to 20 g of a simple carbohydrate
D. 25 to 30 g of a simple carbohydrate

Explanation: ### Explanation **Concept Overview: The "Rule of 15"** The management of acute hypoglycemia in a conscious patient follows the **"Rule of 15."** When blood glucose falls below 70 mg/dL [1], the immediate goal is to raise it quickly using rapidly absorbable, simple carbohydrates. Clinical guidelines (ADA/RSSDI) recommend **15 grams** of glucose as the standard initial dose. This amount is sufficient to raise blood glucose by approximately 30–45 mg/dL within 15 minutes without causing excessive rebound hyperglycemia. **Analysis of Options:** * **Option B (10 to 15 g) - Correct:** This range aligns with standard protocols. Examples include 3–4 glucose tablets, 1/2 cup (120 ml) of fruit juice/regular soda, or 1 tablespoon of honey/sugar. * **Option A (2 to 5 g) - Incorrect:** This dose is insufficient to reverse neuroglycopenic symptoms or safely raise blood glucose levels above the hypoglycemic threshold. * **Options C & D (18 to 30 g) - Incorrect:** While these amounts will correct hypoglycemia, they often lead to **rebound hyperglycemia** and subsequent glycemic variability, which is detrimental in patients with brittle diabetes or cardiovascular comorbidities like angina. **NEET-PG High-Yield Pearls:** 1. **Whipple’s Triad:** Essential for diagnosis—(1) Symptoms of hypoglycemia [1], (2) Low plasma glucose [1], (3) Relief of symptoms after glucose administration. 2. **Beta-Blockers Warning:** Since this patient has hypertension and angina, she might be on beta-blockers. Note that non-selective beta-blockers can **mask** adrenergic symptoms (tachycardia, tremors) but **not** cholinergic symptoms (diphoreis). 3. **Refractory Cases:** If the patient is unconscious or NPO, the treatment of choice is **IV Dextrose (25% or 50%)** or **IM/Subcutaneous Glucagon**. 4. **Follow-up:** Once the glucose is >70 mg/dL, the patient should consume a complex carbohydrate + protein snack (e.g., bread with cheese) to maintain euglycemia.

Question 714: All of the following conditions are known to cause diabetes insipidus except?

A. Multiple sclerosis (Correct Answer)
B. Head injury
C. Histiocytosis
D. Viral encephalitis

Explanation: Diabetes Insipidus (DI) results from either a deficiency of Antidiuretic Hormone (ADH/Vasopressin) due to hypothalamic-pituitary pathology (**Central DI**) or resistance to its action in the kidneys (**Nephrogenic DI**). **Why Multiple Sclerosis (Option A) is the correct answer:** Multiple Sclerosis is a demyelinating disease primarily affecting the white matter of the brain and spinal cord [3, 4]. While it can involve various CNS regions, it **rarely, if ever, involves the hypothalamic-pituitary axis** to a degree that causes Diabetes Insipidus. Therefore, it is not considered a standard cause of DI. **Why the other options are incorrect (Causes of Central DI):** * **Head Injury (Option B):** Trauma is a leading cause of Central DI. It can cause shearing of the pituitary stalk or damage to the supraoptic and paraventricular nuclei of the hypothalamus [1]. * **Histiocytosis (Option C):** Langerhans Cell Histiocytosis (LCH) is a classic cause of DI [1]. Histiocytic infiltration of the pituitary stalk leads to thickening and loss of the "posterior pituitary bright spot" on MRI. * **Viral Encephalitis (Option D):** Inflammatory and infectious processes (including viral encephalitis, meningitis, or tuberculosis) can cause transient or permanent damage to the ADH-producing neurons in the hypothalamus [1]. **NEET-PG High-Yield Pearls:** * **Most common cause of Central DI:** Idiopathic (30-50%), followed by trauma and post-neurosurgery. * **MRI Finding:** The absence of the normal **"Posterior Pituitary Bright Spot"** on T1-weighted images is a hallmark of Central DI. * **Diagnosis:** The **Water Deprivation Test** is the gold standard. Central DI shows a >50% increase in urine osmolality after exogenous desmopressin administration. * **Drug of Choice:** Desmopressin (dDAVP) for Central DI; Thiazides/Amiloride for Nephrogenic DI.

Question 715: A patient has IDDM diagnosed at age 15 years. What is the most reliable indicator for diabetic nephropathy?

A. Urine albumin < 50 mg per day in 3 consecutive samples
B. Urinary protein >550 mg per day for 3 consecutive samples (Correct Answer)
C. Development of diabetic retinopathy
D. Hematuria

Explanation: **Explanation:** Diabetic Nephropathy (DN) is a clinical syndrome characterized by persistent albuminuria, a decline in GFR, and elevated blood pressure. In the context of Type 1 Diabetes (IDDM), the diagnosis of **Overt Nephropathy** (Stage 4) is traditionally defined by persistent proteinuria (>500 mg/24h) [1]. **Why Option B is Correct:** The presence of **urinary protein >500-550 mg/day** in at least two to three consecutive samples over 3–6 months is the hallmark of established diabetic nephropathy [1]. At this stage, the glomerular basement membrane damage is significant enough to allow macroalbuminuria, which is highly predictive of a progressive decline in renal function [1], [2]. **Analysis of Incorrect Options:** * **Option A:** Urine albumin <50 mg/day is within the normal range (Normal <30 mg/day). Microalbuminuria (the earliest clinical sign) is defined as 30–300 mg/day [3]. * **Option C:** While diabetic retinopathy is highly correlated with nephropathy (especially in Type 1 DM), it is a marker of generalized microvascular damage rather than a direct indicator of the renal status itself. * **Option D:** Hematuria is uncommon in isolated diabetic nephropathy. Its presence usually suggests an alternative diagnosis like glomerulonephritis or urolithiasis [2]. **NEET-PG High-Yield Pearls:** 1. **Earliest Sign:** The first functional change is **Hyperfiltration** (Increased GFR); the first clinical sign is **Microalbuminuria** [3]. 2. **Pathognomonic Feature:** **Kimmelstiel-Wilson (KW) nodules** (nodular glomerulosclerosis) on renal biopsy [1]. 3. **The "Rule of Retinopathy":** In Type 1 DM, nephropathy is almost always accompanied by retinopathy. If a Type 1 patient has proteinuria but *no* retinopathy, look for other causes of renal disease. 4. **ACE Inhibitors/ARBs:** These are the drugs of choice as they reduce intraglomerular pressure by dilating the efferent arteriole.

Question 716: A short-statured boy with rhizomelic limbs and brachydactyly is a feature of which condition?

A. Achondroplasia (Correct Answer)
B. Laron dwarfism
C. Hypothyroidism
D. Morquio disease

Explanation: ### Explanation **Achondroplasia** is the most common cause of disproportionate short stature [1]. It is an autosomal dominant condition caused by a gain-of-function mutation in the **FGFR3 gene**, which inhibits chondrocyte proliferation at the epiphyseal growth plate [1]. 1. **Why Achondroplasia is correct:** * **Rhizomelic shortening:** This refers to the disproportionate shortening of the proximal segments of limbs (humerus and femur), a hallmark of achondroplasia [1]. * **Brachydactyly:** Shortening of the fingers and toes is characteristic, often presenting as a **"Trident hand"** (increased space between the 3rd and 4th digits). * Other features include macrocephaly, frontal bossing, and midface hypoplasia [1]. 2. **Why other options are incorrect:** * **Laron dwarfism:** Caused by growth hormone (GH) receptor insensitivity. It results in **proportionate** short stature with high GH levels and low IGF-1 levels. * **Hypothyroidism:** Congenital hypothyroidism (Cretinism) causes stunted growth and delayed bone age, but it is typically associated with intellectual disability, coarse facies, and a protuberant abdomen rather than specific rhizomelic limb shortening. * **Morquio disease (MPS IV):** A mucopolysaccharidosis characterized by short-trunk dwarfism (spondyloepiphyseal dysplasia), corneal clouding, and odontoid hypoplasia, rather than isolated rhizomelic limb shortening. **Clinical Pearls for NEET-PG:** * **Inheritance:** 80% of cases are due to **de novo mutations** associated with advanced paternal age [1]. * **Radiology:** Look for "squaring" of iliac wings (Champagne glass pelvis) and narrowing of the interpedicular distance in the lumbar spine. * **Intelligence:** Individuals with achondroplasia typically have **normal intelligence** and a normal lifespan.

Question 717: Intravenous administration of two liters of normal saline over four hours will primarily stimulate the secretion of which hormone?

A. Atrial natriuretic peptide (Correct Answer)
B. Interleukin-2
C. Tumor necrosis factor-alpha
D. Prostaglandins

Explanation: ### Explanation **Correct Option: A. Atrial Natriuretic Peptide (ANP)** The primary physiological response to rapid volume expansion (such as the infusion of 2 liters of normal saline) is the stretching of the cardiac atria. [2] 1. **Mechanism:** Intravenous saline increases the effective circulating volume and venous return. This leads to increased **atrial stretch**, which triggers the release of **Atrial Natriuretic Peptide (ANP)** from the atrial myocytes. [2] 2. **Action:** ANP acts to counteract volume overload by promoting **natriuresis** (sodium excretion) and **diuresis** (water excretion) at the renal tubules. [1] It also causes systemic vasodilation and inhibits the Renin-Angiotensin-Aldosterone System (RAAS). [1] --- ### Why Other Options are Incorrect: * **B. Interleukin-2 (IL-2):** This is a cytokine primarily involved in the immune response, specifically the proliferation of T-lymphocytes. It is triggered by antigen presentation, not by hemodynamic changes. * **C. Tumor Necrosis Factor-alpha (TNF-alpha):** This is a pro-inflammatory cytokine released during acute inflammation, infection, or malignancy. It is not regulated by fluid volume status. * **D. Prostaglandins:** While certain prostaglandins (like PGE2) play a role in renal vasodilation, they are not the primary hormone "stimulated" by acute volume expansion. In fact, volume expansion typically leads to a decrease in vasoconstrictive mediators. [3] --- ### NEET-PG High-Yield Pearls: * **ANP vs. BNP:** While ANP is released from the **atria** in response to stretch, **B-type Natriuretic Peptide (BNP)** is released from the **ventricles** in response to increased ventricular pressure or volume (used clinically as a marker for Heart Failure). [2] * **Second Messenger:** ANP and BNP both act via the **cyclic GMP (cGMP)** pathway. [3] * **Effect on RAAS:** ANP is a potent antagonist of the RAAS; it decreases renin secretion and directly inhibits aldosterone synthesis in the adrenal cortex. [4] * **Clinical Correlation:** In conditions like SIADH, ANP levels may rise due to volume expansion, contributing to the characteristic "euvolemic hyponatremia" by promoting sodium loss.

Question 718: What is the most common cause of hyperparathyroidism?

A. Solitary adenoma (Correct Answer)
B. Chief cell hyperplasia
C. Multiple adenoma
D. Werner's syndrome

Explanation: **Explanation:** Hyperparathyroidism is classified into primary, secondary, and tertiary types. **Primary Hyperparathyroidism (PHPT)** is characterized by autonomous overproduction of parathyroid hormone (PTH), leading to hypercalcemia. **1. Why Solitary Adenoma is Correct:** A **solitary parathyroid adenoma** is the most common cause of PHPT, accounting for approximately **85-90%** of cases [1], [2]. It typically involves a single gland (usually the inferior parathyroid) that becomes enlarged and hyperfunctional due to sporadic mutations (e.g., *CCND1* or *MEN1* genes). **2. Analysis of Incorrect Options:** * **B. Chief cell hyperplasia:** This involves all four parathyroid glands. It accounts for about **10-15%** of cases and is more frequently associated with hereditary syndromes. * **C. Multiple adenoma:** This is rare, occurring in less than **5%** of patients. It involves two or more enlarged glands while the others remain normal. * **D. Werner’s Syndrome (MEN 1):** While PHPT is the most common and earliest manifestation of MEN 1 (3Ps: Parathyroid, Pituitary, Pancreas), this syndrome is a rare genetic cause. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common presentation:** Asymptomatic hypercalcemia (detected on routine screening) [2]. * **Classic Symptom Triad:** "Stones (renal calculi), bones (osteitis fibrosa cystica), and abdominal groans (peptic ulcers/pancreatitis)" [1]. * **Biochemical Hallmark:** Elevated Serum Calcium + Elevated/Inappropriately Normal PTH + Low Serum Phosphate [2]. * **Localization:** **Sestamibi Scan** (Technetium-99m) is the gold standard for localizing an adenoma before surgery [1]. * **Definitive Treatment:** Surgical excision (Parathyroidectomy).

Question 719: A young patient presented with hypertension and a urinary VMA of 14 mg/24 hours. What is the most likely underlying cause?

A. Medullary carcinoma of the thyroid (Correct Answer)
B. Von Hippel-Lindau syndrome
C. Graves' disease
D. Pseudohypoparathyroidism

Explanation: The patient presents with hypertension and an elevated urinary **Vanillylmandelic Acid (VMA)** level (Normal: <7 mg/24 hours). VMA is a metabolic byproduct of catecholamines (epinephrine and norepinephrine), and its elevation is a classic biochemical marker for **Pheochromocytoma**. [1] **1. Why Medullary Carcinoma of the Thyroid (MTC) is correct:** The question implies a clinical association. MTC is a key component of **Multiple Endocrine Neoplasia (MEN) type 2A and 2B**. In these autosomal dominant syndromes, MTC is frequently associated with **Pheochromocytoma**. [1] In a young patient with signs of catecholamine excess, the presence of MTC is the most likely underlying syndromic cause among the given choices. **2. Analysis of Incorrect Options:** * **Von Hippel-Lindau (VHL) syndrome:** While VHL is associated with pheochromocytoma, the question specifically points toward MTC as the "underlying cause" or associated finding in the context of MEN syndromes, which are more frequently tested in this pattern. (Note: If both were options, the context of MTC usually points to the RET oncogene). * **Graves' disease:** An autoimmune hyperthyroidism. While it causes tachycardia and systolic hypertension, it does not increase urinary VMA levels. * **Pseudohypoparathyroidism:** Characterized by end-organ resistance to PTH (low calcium, high phosphate). It has no association with catecholamine excess or VMA. **Clinical Pearls for NEET-PG:** * **Rule of 10s for Pheochromocytoma:** 10% bilateral, 10% malignant, 10% pediatric, 10% extra-adrenal (Paraganglioma). * **MEN 2A:** MTC + Pheochromocytoma + Hyperparathyroidism. [1] * **MEN 2B:** MTC + Pheochromocytoma + Mucosal neuromas/Marfanoid habitus. * **Screening:** Plasma free metanephrines (most sensitive) or 24-hour urinary metanephrines/VMA (specific). * **Pre-op Management:** Always give **Alpha-blockers** (e.g., Phenoxybenzamine) *before* Beta-blockers to avoid a hypertensive crisis. [1]

Question 720: The occurrence of hyperthyroidism following administration of supplemental iodine to subjects with endemic iodine deficiency goiter is known as what?

A. Jod-Basedow effect (Correct Answer)
B. Wolff-Chaokoff effect
C. Thyrotoxicosis factitia
D. De Quervain's thyroiditis

Explanation: ### Explanation **1. Why the Correct Answer is Right (Jod-Basedow Effect)** The **Jod-Basedow effect** refers to iodine-induced hyperthyroidism. It typically occurs when supplemental iodine is administered to individuals who have long-standing iodine deficiency and multinodular goiters. In these patients, areas of the thyroid gland have become autonomous (functioning independently of TSH). When a sudden "load" of iodine (the substrate for thyroid hormone) is provided, these autonomous nodules overproduce thyroxine (T4) and triiodothyronine (T3), leading to thyrotoxicosis. **2. Analysis of Incorrect Options** * **Wolff-Chaikoff Effect:** This is the physiological opposite. It is the temporary **inhibition** of thyroid hormone synthesis following the administration of a large bolus of iodine. It is a protective mechanism to prevent excessive hormone production. * **Thyrotoxicosis Factitia:** This refers to hyperthyroidism caused by the intentional or accidental ingestion of exogenous thyroid hormones (e.g., levothyroxine), not iodine supplementation [1]. It is characterized by low serum thyroglobulin levels and suppressed iodine uptake [1]. * **De Quervain’s Thyroiditis:** Also known as Subacute Granulomatous Thyroiditis, this is a painful inflammatory condition of the thyroid, usually following a viral infection [2]. While it causes transient hyperthyroidism due to the release of stored hormones (leakage), it is not triggered by iodine intake [2]. Antithyroid drugs are of no benefit because hormone synthesis is impaired rather than enhanced [2]. **3. NEET-PG High-Yield Pearls** * **Jod-Basedow** can also be triggered by iodine-containing contrast media or drugs like **Amiodarone** (Type 1). * **Wolff-Chaikoff** is the principle behind using Lugol’s iodine to prepare patients for thyroidectomy (it decreases the vascularity and size of the gland). * **Memory Trick:** **J**od-Basedow = **J**ump in thyroid levels (Hyper); **W**olff-Chaikoff = **W**ithdrawal/Waning of levels (Hypo).

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Diabetes Mellitus

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Adrenal Gland Disorders

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Multiple Endocrine Neoplasia

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Endocrine Emergencies

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