Endocrinology — MCQs

A 53-year-old woman with a past medical history of chronic kidney disease due to diabetic nephropathy is noted to have hyperphosphatemia and hypocalcemia on routine electrolyte measurement. The disturbance is likely a result of metabolic bone disease seen in patients with chronic kidney disease. Which of the following findings is most likely associated with this electrolyte disturbance?

Q665Easy

What is the treatment for neurogenic diabetes insipidus?

Q666Easy

All of the following are features of pheochromocytoma except?

Q667Medium

Hypogonadotropic hypogonadism with diabetes mellitus is seen in which of the following conditions?

Q668Easy

MEN 1 syndrome is associated with all EXCEPT:

Q669Medium

Which of the following tests is used to distinguish primary hyperparathyroidism from familial benign hypercalcemia?

Q670Medium

A 20-year-old male is admitted to the ICU for diabetic ketoacidosis (DKA). His mother reports increased thirst and frequent urination recently. He has no prior diabetes diagnosis and no family history of diabetes. His BMI is 42 kg/m2. Anti-GAD antibodies and anti-islet cell antibodies (ICA) are not detected. Which of the following statements is true regarding this patient?

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 661: What is the drug of choice for post-menopausal osteoporosis?

A. Raloxifene
B. Tamoxifene
C. Estrogen
D. Alendronate (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Alendronate** **Why Alendronate is the Drug of Choice:** Bisphosphonates, specifically **Alendronate**, are considered the first-line therapy (Drug of Choice) for post-menopausal osteoporosis [1]. They work by inhibiting **osteoclast-mediated bone resorption**. Alendronate has been proven to significantly increase Bone Mineral Density (BMD) and reduce the risk of both vertebral and hip fractures, which are the primary clinical goals in managing osteoporosis. **Analysis of Incorrect Options:** * **A. Raloxifene:** This is a Selective Estrogen Receptor Modulator (SERM) [1]. While it reduces the risk of vertebral fractures and decreases the risk of invasive breast cancer, it is **not** effective in preventing hip fractures [1]. Thus, it is a second-line agent. * **B. Tamoxifene:** Primarily used in the treatment and prophylaxis of breast cancer. While it has some protective effect on bone density, it is not used as a primary treatment for osteoporosis due to its side effect profile (e.g., risk of endometrial cancer). * **C. Estrogen:** Hormone Replacement Therapy (HRT) is effective in preventing bone loss; however, it is no longer the first-line treatment due to increased risks of breast cancer, stroke, and venous thromboembolism (VTE) [1]. It is generally reserved for women who also have significant vasomotor symptoms [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Administration:** Alendronate must be taken on an empty stomach with a full glass of water, and the patient must remain upright for 30 minutes to prevent **pill-induced esophagitis**. * **Side Effects:** Long-term use is associated with rare but high-yield complications: **Osteonecrosis of the Jaw (ONJ)** [1] and **Atypical Subtrochanteric Femoral Fractures**. * **Contraindication:** Bisphosphonates are contraindicated in patients with severe renal impairment (CrCl <35 mL/min) and esophageal disorders (e.g., achalasia). * **Zoledronic Acid:** This is the most potent IV bisphosphonate, given once yearly [1].

Question 662: Which of the following are monogenic and autosomal dominant causes of hypertension?

A. Familial Conn's syndrome and Glucocorticoid-remediable hyperaldosteronism (Correct Answer)
B. Pregnancy-induced hypertension and Familial Conn's syndrome
C. Familial Conn's syndrome and 17-α hydroxylase deficiency
D. Glucocorticoid-remediable hyperaldosteronism and 17-α hydroxylase deficiency

Explanation: The correct answer is **A**. This question tests your knowledge of **Monogenic Hypertension**, a group of rare disorders caused by single-gene mutations, typically inherited in an **Autosomal Dominant (AD)** fashion, leading to mineralocorticoid excess. 1. **Why Option A is correct:** * **Glucocorticoid-remediable hyperaldosteronism (GRA/Familial Hyperaldosteronism Type I):** Caused by a chimeric gene crossover between *CYP11B1* and *CYP11B2*. It is AD and results in ACTH-dependent aldosterone secretion. * **Familial Conn’s Syndrome (Familial Hyperaldosteronism Type II/III):** These are AD conditions (e.g., *KCNJ5* mutations) causing autonomous aldosterone production. Both conditions present with hypertension, hypokalemia, and low renin. 2. **Why other options are incorrect:** * **Pregnancy-induced hypertension (Option B):** This is a complex, polygenic, and multifactorial condition, not a monogenic AD disorder. * **17-α hydroxylase deficiency (Options C & D):** While this causes mineralocorticoid-induced hypertension, it is inherited in an **Autosomal Recessive (AR)** pattern. It also presents with delayed puberty/hypogonadism due to impaired sex steroid synthesis. **Clinical Pearls for NEET-PG:** * **Liddle Syndrome:** Another high-yield AD cause of monogenic hypertension. It involves a "gain-of-function" mutation in the ENaC channel. Note: Aldosterone levels are **low** in Liddle syndrome, unlike GRA. * **GRA Diagnosis:** Suspect GRA if hypertension is early-onset and family history is strong. It is uniquely treated with low-dose **Dexamethasone** (which suppresses ACTH). * **Key Differentiator:** In monogenic hypertension, the **Plasma Renin Activity (PRA)** is almost always **suppressed**.

Question 663: Calcification in basal ganglia is seen in which of the following conditions?

A. Hypothyroidism
B. Hypoparathyroidism (Correct Answer)
C. Hypopituitarism
D. Hypoaldosteronism

Explanation: **Explanation:** **Basal Ganglia Calcification (BGC)** is a classic radiological finding associated with disorders of calcium and phosphate metabolism. **Why Hypoparathyroidism is correct:** In hypoparathyroidism (and pseudohypoparathyroidism), the deficiency or resistance to Parathyroid Hormone (PTH) leads to **hypocalcemia** and **hyperphosphatemia** [1]. When the calcium-phosphate product in the serum remains elevated or fluctuates, it leads to the deposition of calcium hydroxyapatite crystals in the walls of small blood vessels. The basal ganglia (specifically the globus pallidus) are highly metabolic areas with a unique vascular supply, making them prone to these deposits. This is often referred to as **Fahr’s Syndrome** when associated with an endocrine cause. **Why other options are incorrect:** * **Hypothyroidism:** While it can cause various neurological symptoms (like delayed relaxation of reflexes), it does not typically cause intracranial calcification. * **Hypopituitarism:** This involves deficiencies in growth hormone, TSH, or ACTH, which do not directly impact the calcium-phosphate homeostasis required for basal ganglia calcification. * **Hypoaldosteronism:** This primarily affects sodium, potassium, and blood pressure regulation (leading to hyperkalemia and metabolic acidosis) without affecting cerebral mineral deposition. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** The **Globus Pallidus** is the most frequent site of calcification in hypoparathyroidism. * **Clinical Presentation:** Patients may present with extrapyramidal symptoms (parkinsonism, chorea, or athetosis) or seizures. * **Pseudohypoparathyroidism:** This condition (Albright’s Hereditary Osteodystrophy) actually shows **more extensive** basal ganglia calcification than primary hypoparathyroidism [1]. * **Differential Diagnosis:** Other causes of BGC include Fahr’s Disease (idiopathic/familial), Down syndrome, and certain infections (TORCH).

Question 664: A 53-year-old woman with a past medical history of chronic kidney disease due to diabetic nephropathy is noted to have hyperphosphatemia and hypocalcemia on routine electrolyte measurement. The disturbance is likely a result of metabolic bone disease seen in patients with chronic kidney disease. Which of the following findings is most likely associated with this electrolyte disturbance?

A. Lethargy
B. Neuromuscular irritability (Correct Answer)
C. Anorexia
D. Tachyarrhythmias

Explanation: The patient presents with **hypocalcemia** and **hyperphosphatemia** secondary to Chronic Kidney Disease (CKD), a condition known as **CKD-Mineral and Bone Disorder (CKD-MBD)**. In CKD, the kidneys fail to excrete phosphate and cannot adequately convert 25-hydroxyvitamin D into its active form, 1,25-dihydroxyvitamin D (calcitriol) [3], [4]. This leads to decreased intestinal calcium absorption and reciprocal hypocalcemia. **1. Why Neuromuscular Irritability is Correct:** Low extracellular calcium levels decrease the threshold for depolarization of excitable membranes. This increases the permeability of neuronal membranes to sodium ions, leading to spontaneous action potentials. Clinically, this manifests as **neuromuscular irritability**, which includes: * **Paresthesias** (perioral and fingertips) [1]. * **Tetany** (involuntary muscle contractions). * **Chvostek sign** (facial twitching on tapping the facial nerve). * **Trousseau sign** (carpopedal spasm induced by BP cuff inflation). **2. Why the other options are incorrect:** * **Lethargy and Anorexia:** These are classic symptoms of **hypercalcemia**, not hypocalcemia [2]. Hypercalcemia "moans" include CNS depression and GI upset. * **Tachyarrhythmias:** Hypocalcemia typically causes **QT interval prolongation**, which can lead to Torsades de Pointes (a form of ventricular tachycardia), but it is more classically associated with bradycardia or heart block rather than simple tachyarrhythmias. **High-Yield Clinical Pearls for NEET-PG:** * **CKD-MBD Triad:** Hyperphosphatemia, Hypocalcemia, and Secondary Hyperparathyroidism [3]. * **ECG in Hypocalcemia:** Prolonged QT interval (specifically the ST segment). * **Phosphate Binders:** Used in CKD to manage hyperphosphatemia (e.g., Sevelamer, Calcium acetate). * **Hungry Bone Syndrome:** Severe hypocalcemia seen post-parathyroidectomy in patients with long-standing hyperparathyroidism.

Question 665: What is the treatment for neurogenic diabetes insipidus?

A. Vasopressin
B. Desmopressin (Correct Answer)
C. Terlipressin
D. Amiodarone

Explanation: **Explanation:** **Neurogenic (Central) Diabetes Insipidus (DI)** is characterized by a deficiency in the synthesis or release of Antidiuretic Hormone (ADH) from the posterior pituitary [1]. This leads to the inability to concentrate urine, resulting in polyuria and polydipsia. **Why Desmopressin is the Correct Answer:** **Desmopressin (dDAVP)** is a synthetic analogue of vasopressin and is the **drug of choice** for Central DI [1]. It is highly selective for **V2 receptors** located in the renal collecting ducts, which mediate the antidiuretic effect [2]. Unlike natural vasopressin, it has minimal activity at V1 receptors (vasoconstrictor receptors), meaning it does not cause significant hypertension or cramping [2]. It also has a longer half-life, allowing for twice-daily dosing via nasal spray, oral, or parenteral routes. **Analysis of Incorrect Options:** * **Vasopressin (A):** While it works, it is non-selective (stimulates both V1 and V2) and has a very short half-life (minutes), making it impractical for long-term maintenance compared to Desmopressin. * **Terlipressin (C):** This is a prodrug of lysine vasopressin with high affinity for **V1 receptors** [2]. It is primarily used in the management of esophageal variceal bleeding and Hepatorenal Syndrome, not DI. * **Amiodarone (D):** This is a Class III antiarrhythmic drug. It is not used to treat DI; in fact, it is more commonly associated with thyroid dysfunction. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** The **Water Deprivation Test** is used to diagnose DI [1]. In Central DI, the administration of exogenous Desmopressin will result in a significant increase in urine osmolality (>50%), whereas Nephrogenic DI shows little to no response. * **Nephrogenic DI Treatment:** The drug of choice is **Thiazide diuretics** (paradoxical effect) or Amiloride (especially if lithium-induced). * **Pregnancy:** Desmopressin is safe to use for DI during pregnancy.

Question 666: All of the following are features of pheochromocytoma except?

A. Hypertensive paroxysm
B. Headache
C. Orthostatic hypotension
D. Wheezing (Correct Answer)

Explanation: **Explanation:** Pheochromocytoma is a catecholamine-secreting tumor arising from the chromaffin cells of the adrenal medulla. The clinical presentation is primarily driven by the excessive release of epinephrine and norepinephrine. **Why Wheezing is the Correct Answer:** Wheezing is not a feature of pheochromocytoma. In fact, catecholamines (especially epinephrine) act on **$\beta_2$-adrenergic receptors** in the bronchioles to cause **bronchodilation**. Therefore, pheochromocytoma would physiologically oppose wheezing rather than cause it. Wheezing is more characteristic of **Carcinoid Syndrome**, which is a common differential diagnosis. **Analysis of Incorrect Options:** * **Hypertensive Paroxysm:** This is the hallmark of the disease. Sudden bursts of catecholamines cause severe vasoconstriction ($\alpha_1$ effect), leading to episodic, life-threatening hypertension. * **Headache:** This is the most common symptom during a paroxysm (seen in >90% of symptomatic patients) due to the sudden increase in cerebral blood pressure. * **Orthostatic Hypotension:** Though counterintuitive, this is a classic feature. It occurs due to **decreased intravascular volume** (chronic vasoconstriction leads to pressure natriuresis) and impaired autonomic reflexes. **High-Yield Clinical Pearls for NEET-PG:** * **The Rule of 10s:** 10% bilateral, 10% malignant, 10% pediatric, 10% extra-adrenal (Paragangliomas), and 10% familial. * **The Classic Triad:** Episodic headache, sweating (diaphoresis), and tachycardia. * **Diagnosis:** Best initial screening test is **24-hour urinary fractionated metanephrines** or plasma free metanephrines. * **Management:** Always give **$\alpha$-blockers first** (e.g., Phenoxybenzamine) before $\beta$-blockers to avoid an unopposed $\alpha$-mediated hypertensive crisis.

Question 667: Hypogonadotropic hypogonadism with diabetes mellitus is seen in which of the following conditions?

A. Kallman Syndrome
B. Hypothalamic hamartoma
C. Granulomatous hypophysitis
D. Prader-Willi Syndrome (Correct Answer)

Explanation: **Explanation:** **Prader-Willi Syndrome (PWS)** is the correct answer because it is a complex multisystem genetic disorder (deletion of the paternal copy of chromosome 15q11-q13) characterized by hypothalamic dysfunction [1]. This dysfunction leads to **Hypogonadotropic Hypogonadism** (due to GnRH deficiency) and **Hyperphagia**, which results in morbid obesity [1]. The severe obesity and associated insulin resistance frequently lead to the development of **Type 2 Diabetes Mellitus** in these patients. **Analysis of Incorrect Options:** * **Kallman Syndrome:** Characterized by hypogonadotropic hypogonadism and anosmia due to failure of GnRH neuron migration. While it causes infertility, it is not classically associated with obesity or diabetes mellitus. * **Hypothalamic Hamartoma:** These are benign tumors typically presenting with **Precocious Puberty** (due to ectopic GnRH secretion) and gelastic seizures, rather than hypogonadism. * **Granulomatous Hypophysitis:** An inflammatory condition of the pituitary (often associated with Sarcoidosis or TB). While it can cause panhypopituitarism (including hypogonadism), it does not have a primary association with diabetes mellitus; in fact, pituitary failure often *increases* insulin sensitivity. **High-Yield Clinical Pearls for NEET-PG:** * **PWS Triad:** Hypotonia (infancy), Hyperphagia/Obesity (childhood), and Hypogonadism. * **Genetics:** Paternal deletion of 15q11-q13 or Maternal Uniparental Disomy (UPD). * **Hand/Foot findings:** Small hands and feet (acromicria) are characteristic. * **Contrast:** **Angelman Syndrome** involves the same locus but results from *maternal* deletion ("Happy Puppet" syndrome).

Question 668: MEN 1 syndrome is associated with all EXCEPT:

A. Pancreatic tumors
B. Anterior pituitary adenomas
C. Parathyroid adenoma
D. Medullary carcinoma of the thyroid (Correct Answer)

Explanation: **Explanation:** Multiple Endocrine Neoplasia Type 1 (MEN 1), also known as **Wermer’s Syndrome**, is an autosomal dominant disorder caused by a mutation in the *MEN1* gene (encoding the protein Menin). It is classically characterized by the **"3 Ps"**: Parathyroid, Pancreas, and Pituitary. **Why Medullary Carcinoma of the Thyroid (MTC) is the correct answer:** MTC is a hallmark feature of **MEN 2A and MEN 2B**, not MEN 1. MTC arises from the parafollicular C-cells of the thyroid and is associated with mutations in the *RET* proto-oncogene. Its presence in a clinical vignette should immediately point toward MEN 2. **Analysis of Incorrect Options:** * **Parathyroid Adenoma:** This is the most common manifestation of MEN 1 (occurring in >95% of patients). It typically presents as multiglandular hyperplasia leading to primary hyperparathyroidism. * **Pancreatic Tumors:** These are the second most common feature. Gastrinomas (Zollinger-Ellison Syndrome) are the most frequent, followed by Insulinomas. * **Anterior Pituitary Adenomas:** These occur in about 30-40% of cases. Prolactinomas are the most common subtype, followed by GH-secreting adenomas (Acromegaly). **High-Yield Clinical Pearls for NEET-PG:** * **MEN 1 (Wermer’s):** 3 Ps (Parathyroid, Pancreas, Pituitary). Also associated with adrenal cortical tumors, facial angiofibromas, and lipomas. * **MEN 2A (Sipple’s):** 1 P (Parathyroid), 1 M (MTC), 1 P (Pheochromocytoma). * **MEN 2B (Williams):** 1 M (MTC), 1 P (Pheochromocytoma), Marfanoid habitus, and Mucosal neuromas. (Note: No Parathyroid involvement in 2B). * **Screening:** The first biochemical abnormality usually detected in MEN 1 is hypercalcemia due to hyperparathyroidism.

Question 669: Which of the following tests is used to distinguish primary hyperparathyroidism from familial benign hypercalcemia?

A. Serum PTH levels
B. Serum calcium levels
C. Urinary calcium levels (Correct Answer)
D. Serum phosphorus levels

Explanation: **Explanation:** The clinical distinction between **Primary Hyperparathyroidism (PHPT)** and **Familial Hypocalciuric Hypercalcemia (FHH)**—also known as familial benign hypercalcemia—is critical because PHPT requires surgery, while FHH is a benign condition where surgery is ineffective. **Why Urinary Calcium is the Correct Answer:** The underlying pathophysiology of FHH involves an inactivating mutation in the **Calcium-Sensing Receptor (CaSR)**. This leads to a higher "set-point" for calcium, causing the kidneys to reabsorb calcium excessively despite high serum levels. * **FHH:** Characterized by **low urinary calcium excretion** (Hypocalciuria). The Calcium-to-Creatinine Clearance Ratio (**CCCR**) is typically **<0.01**. * **PHPT:** Characterized by **high or normal urinary calcium excretion** (Hypercalciuria) because the high filtered load of calcium eventually exceeds the reabsorptive capacity. The CCCR is typically **>0.02**. **Analysis of Incorrect Options:** * **A. Serum PTH levels:** Both conditions present with elevated or inappropriately normal PTH levels, making this test non-discriminatory. * **B. Serum calcium levels:** Both conditions present with hypercalcemia. * **D. Serum phosphorus levels:** Both conditions can present with low or low-normal serum phosphorus due to the phosphaturic effects of PTH. **NEET-PG High-Yield Pearls:** * **CCCR Formula:** (Urinary Ca × Serum Cr) / (Serum Ca × Urinary Cr). * **FHH Inheritance:** Autosomal Dominant. * **Clinical Clue:** If a patient has asymptomatic hypercalcemia, a family history of "failed" parathyroid surgeries, and low urinary calcium, suspect FHH. * **Management:** PHPT often requires parathyroidectomy; FHH requires no treatment (it is "benign").

Question 670: A 20-year-old male is admitted to the ICU for diabetic ketoacidosis (DKA). His mother reports increased thirst and frequent urination recently. He has no prior diabetes diagnosis and no family history of diabetes. His BMI is 42 kg/m2. Anti-GAD antibodies and anti-islet cell antibodies (ICA) are not detected. Which of the following statements is true regarding this patient?

A. Due to the young age of onset, type 1 diabetes is suspected.
B. Because of the presentation with diabetic ketoacidosis, type 1 diabetes is suspected.
C. The patient has maturity-onset diabetes of the young.
D. The patient has type 2 diabetes mellitus. (Correct Answer)

Explanation: ### Explanation The correct answer is **D. The patient has type 2 diabetes mellitus.** This patient presents with **Ketosis-Prone Type 2 Diabetes (KPD)**, also known as "Flatbush Diabetes." While DKA is classically associated with Type 1 Diabetes (T1DM), it is increasingly seen in patients with Type 2 Diabetes (T2DM), particularly those with obesity [1]. **Why Option D is correct:** The diagnosis of T2DM is supported by the patient’s **high BMI (42 kg/m²)** and the **absence of pancreatic autoantibodies** (Anti-GAD and ICA). In KPD, patients present with acute insulin deficiency (leading to DKA), often triggered by glucose toxicity which suppresses beta-cell function [1]. With treatment, they later regain significant beta-cell function and can often be managed with oral hypoglycemic agents rather than lifelong insulin [1]. **Why other options are incorrect:** * **Option A & B:** While young age and DKA are "textbook" features of T1DM [2], the presence of morbid obesity and negative autoantibodies strongly point toward T2DM. DKA is no longer considered pathognomonic for T1DM [1]. * **Option C:** Maturity-Onset Diabetes of the Young (MODY) typically presents in non-obese individuals with a strong autosomal dominant family history [3]. This patient has no family history and a high BMI, making MODY unlikely. ### Clinical Pearls for NEET-PG: * **Antibody Testing:** Negative Anti-GAD, ICA, and IA-2 antibodies in a patient with DKA should raise suspicion for Ketosis-Prone T2DM. * **AB Classification:** KPD is often classified using the "Aβ" system (A: Autoantibodies; β: Beta-cell function). This patient fits the **A-β+** category (Antibody negative, preserved beta-cell function). * **Management:** After resolving the initial DKA with insulin, these patients should be re-evaluated for transition to oral drugs (like Metformin) once glucose toxicity resolves [1].

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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