Endocrinology Practice Questions

Q: Which of the following is a testosterone receptor antagonist?

Flutamide. 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.

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

All of the above. 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].

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

Multiple sclerosis. 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.

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

Urinary protein >550 mg per day for 3 consecutive samples. **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.

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

Achondroplasia. ### 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.

Q: What is the most common cause of hyperparathyroidism?

Solitary adenoma. **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 1

Hypercalcemia is seen in all of the following conditions except:

Accepted Answer

Acute pancreatitis

Answer

Hypervitaminosis D

Answer

Addison's disease

Answer

Hyperparathyroidism

Question 2

Which of the following is a testosterone receptor antagonist?

Accepted Answer

Flutamide

Answer

Mifepristone

Answer

Danazol

Answer

Nonoxynol

Question 3

Gynecomastia may be associated with which of the following conditions?

Accepted Answer

All of the above

Answer

Klinefelter's syndrome

Answer

Feminizing tumor of the adrenal gland

Answer

Normal adolescent boys who are rapidly virilizing

Question 4

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?

Accepted Answer

10 to 15 g of a simple carbohydrate

Answer

2 to 5 g of a simple carbohydrate

Answer

18 to 20 g of a simple carbohydrate

Answer

25 to 30 g of a simple carbohydrate

Question 5

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

Accepted Answer

Multiple sclerosis

Answer

Head injury

Answer

Histiocytosis

Answer

Viral encephalitis

Question 6

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

Accepted Answer

Urinary protein >550 mg per day for 3 consecutive samples

Answer

Urine albumin < 50 mg per day in 3 consecutive samples

Answer

Development of diabetic retinopathy

Answer

Hematuria

Question 7

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

Accepted Answer

Achondroplasia

Answer

Laron dwarfism

Answer

Hypothyroidism

Answer

Morquio disease

Question 8

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

Accepted Answer

Atrial natriuretic peptide

Answer

Interleukin-2

Answer

Tumor necrosis factor-alpha

Answer

Prostaglandins

Question 9

What is the most common cause of hyperparathyroidism?

Accepted Answer

Solitary adenoma

Answer

Chief cell hyperplasia

Answer

Multiple adenoma

Answer

Werner's syndrome

Question 10

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

Accepted Answer

Medullary carcinoma of the thyroid

Answer

Von Hippel-Lindau syndrome

Answer

Graves' disease

Answer

Pseudohypoparathyroidism

Endocrinology — MCQs

Endocrinology — MCQs

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