Endocrinology — MCQs

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 81: What is the most common cause of Cushing syndrome?

A. Pituitary tumor
B. Ectopic ACTH producing tumor
C. Steroid supplementation (Correct Answer)
D. Adrenal tumor

Explanation: **Explanation:** The most common cause of **Cushing syndrome** (the clinical state of hypercortisolism) is **Exogenous/Iatrogenic administration of glucocorticoids** [1] (Option C). This occurs in patients receiving long-term steroid therapy for conditions like asthma, rheumatoid arthritis, or autoimmune disorders [1]. **Analysis of Options:** * **Option C (Correct):** Exogenous steroid use is the overall leading cause. It leads to suppressed ACTH levels and bilateral adrenal atrophy due to negative feedback [2]. * **Option A (Incorrect):** A pituitary adenoma (Cushing **Disease**) is the most common cause of **Endogenous** Cushing syndrome (approx. 70% of endogenous cases), but it is less frequent than iatrogenic causes [4]. * **Option B (Incorrect):** Ectopic ACTH production (often from Small Cell Lung Cancer) is a rare cause of endogenous Cushing syndrome [1], typically presenting with rapid onset and severe hypokalemia. * **Option D (Incorrect):** Primary adrenal tumors (adenomas or carcinomas) are ACTH-independent endogenous causes but are less common than pituitary-driven disease [1]. **High-Yield Clinical Pearls for NEET-PG:** 1. **Cushing Syndrome vs. Disease:** "Syndrome" refers to the clinical state of high cortisol from any cause; "Disease" specifically refers to a **Pituitary Adenoma** [4]. 2. **Screening Tests:** The best initial tests are the 24-hour urinary free cortisol, late-night salivary cortisol, or the Low-Dose Dexamethasone Suppression Test (LDDST) [3]. 3. **ACTH Levels:** ACTH is **low** in iatrogenic and adrenal causes (ACTH-independent) and **high** in pituitary and ectopic causes (ACTH-dependent) [2]. 4. **Hyperpigmentation:** Seen only in ACTH-dependent causes (Pituitary/Ectopic) due to the co-secretion of Melanocyte-Stimulating Hormone (MSH).

Question 82: Which of the following is a complication of diabetes mellitus?

A. Cataract (Correct Answer)
B. Rubeosis iridis
C. Retinal detachment
D. Cranial nerve palsy

Explanation: **Explanation:** Diabetes mellitus leads to various ocular complications through metabolic and vascular pathways. **Cataract** is a classic complication that occurs earlier and more frequently in diabetics compared to the general population. The underlying pathophysiology involves the **Polyol pathway**: excess glucose is converted into **sorbitol** by the enzyme *aldose reductase*. Sorbitol is osmotically active and accumulates within the lens, leading to water influx, lens swelling, and eventual opacification. A high-yield variant is the "Snowflake cataract," typically seen in young patients with uncontrolled Type 1 Diabetes. **Analysis of Options:** * **B. Rubeosis iridis:** While this is a complication (neovascularization of the iris), it is secondary to proliferative diabetic retinopathy (PDR) rather than a primary metabolic effect on the lens [1]. * **C. Retinal detachment:** Specifically, *tractional* retinal detachment occurs in advanced PDR due to fibrovascular proliferation [2]. While a complication, it is a late-stage sequela of retinopathy. * **D. Cranial nerve palsy:** Diabetes can cause mononeuropathies (most commonly CN III, IV, or VI). A classic NEET-PG pearl is that **CN III palsy in diabetes is pupil-sparing** (due to ischemic damage to internal fibers, sparing superficial parasympathetic fibers). **Clinical Pearls for NEET-PG:** 1. **Most common cause of blindness** in working-age adults is Diabetic Retinopathy. 2. **First clinical sign** of diabetic retinopathy: Microaneurysms [1]. 3. **Aldose Reductase** is the rate-limiting enzyme in the development of diabetic cataracts. 4. **Refractive changes:** Hyperglycemia can cause temporary blurring of vision due to osmotic changes in the lens shape before a true cataract forms. **Systemic Impact:** Improved glycaemic control is proven to reduce the risk of microvascular complications such as retinopathy [3]. Diabetic microangiopathy specifically contributes to high morbidity and mortality in these patients [4].

Question 83: Which of the following is the leading cause of GHRH mediated acromegaly?

A. Hypothalamic Hamartoma
B. Choristoma
C. Carcinoid tumor (Correct Answer)
D. Pluri-hormonal adenoma

Explanation: Acromegaly is most commonly caused by a GH-secreting pituitary adenoma (>95% of cases). However, in rare instances (<1%), it results from excessive Growth Hormone-Releasing Hormone (GHRH) production, which chronically stimulates the pituitary somatotrophs. **Why Carcinoid Tumor is correct:** Ectopic GHRH secretion is the most common cause of GHRH-mediated acromegaly. Among these, bronchial and gastrointestinal carcinoid tumors (along with pancreatic islet cell tumors) are the leading sources [3]. These tumors secrete GHRH into the systemic circulation, leading to somatotroph hyperplasia and subsequent GH excess. **Analysis of Incorrect Options:** * **Hypothalamic Hamartoma & Choristoma:** These are central (hypothalamic) causes of GHRH excess. While they can cause acromegaly, they are significantly rarer than peripheral ectopic sources like carcinoid tumors. * **Pluri-hormonal Adenoma:** These are pituitary tumors that secrete multiple hormones (e.g., GH and Prolactin) [1]. They cause acromegaly via direct GH secretion, not through GHRH mediation. **NEET-PG High-Yield Pearls:** * **Most common cause of Acromegaly:** Pituitary Adenoma (Somatotroph adenoma) [2]. * **Most common ectopic source of GH:** Extremely rare (e.g., pancreatic or lymphoma); most ectopic cases are actually ectopic **GHRH**. * **Biochemical Hallmark:** Failure to suppress GH levels to <1 mcg/L after an oral glucose tolerance test (OGTT) and elevated IGF-1 levels [1]. * **Imaging:** In GHRH-mediated cases, MRI may show **diffuse pituitary enlargement/hyperplasia** rather than a discrete adenoma.

Question 84: Which of the following is an SGLT2 inhibitor approved for the treatment of type 2 diabetes mellitus?

A. Dulaglutide
B. Pramlintide
C. Canagliflozin (Correct Answer)
D. Nateglinide

Explanation: **Explanation:** **Correct Answer: C. Canagliflozin** Canagliflozin is a Sodium-Glucose Co-transporter 2 (SGLT2) inhibitor [2]. These drugs act on the proximal convoluted tubule (PCT) of the kidney to inhibit glucose reabsorption, leading to therapeutic glucosuria [2]. This mechanism is insulin-independent, making them effective for lowering HbA1c while also providing cardiovascular and renal protection. **Analysis of Incorrect Options:** * **A. Dulaglutide:** This is a **GLP-1 Receptor Agonist** (incretin mimetic) [1]. It is administered subcutaneously and works by stimulating glucose-dependent insulin secretion and slowing gastric emptying [1]. * **B. Pramlintide:** This is a **synthetic Amylin analogue**. It is used as an adjunct to insulin in both Type 1 and Type 2 DM to suppress glucagon secretion and promote satiety. * **C. Nateglinide:** This belongs to the **Meglitinide** class (Glinides). Like sulfonylureas, it acts as an insulin secretagogue by closing ATP-sensitive K+ channels on pancreatic beta cells, but it has a shorter duration of action. **High-Yield Clinical Pearls for NEET-PG:** * **SGLT2 Inhibitors ("-gliflozins"):** Known for "3 Benefits" — Glucose lowering, Weight loss, and Blood pressure reduction. * **Side Effects:** Increased risk of Genitourinary infections (due to glucosuria), Euglycemic Ketoacidosis, and Fourner’s gangrene (rare). * **Cardiorenal Protection:** Empagliflozin and Canagliflozin are specifically noted for reducing the risk of Major Adverse Cardiovascular Events (MACE) and slowing the progression of Chronic Kidney Disease (CKD). * **Dapagliflozin** is now a cornerstone in the management of Heart Failure with reduced Ejection Fraction (HFrEF), even in non-diabetic patients.

Question 85: All are true about cardiac manifestations of carcinoid syndrome, EXCEPT:

A. The cardiac disease in carcinoid syndrome is due to the formation of fibrotic plaques involving the endocardium.
B. Fibrous deposits are most commonly on the ventricular aspect of the tricuspid valve.
C. Cardiac failure is not a feature of carcinoid syndrome. (Correct Answer)
D. Mitral valve lesions are less extensive and frequently affect the tricuspid valve.

Explanation: **Explanation:** Carcinoid heart disease occurs in approximately 50% of patients with carcinoid syndrome, typically resulting from the action of humoral substances like **serotonin (5-HT)** secreted by neuroendocrine tumors (usually metastatic to the liver) [1]. **1. Why Option C is the correct answer (The Exception):** Cardiac failure is, in fact, a **major cause of morbidity and mortality** in carcinoid syndrome. The progressive fibrous thickening of the valves leads to severe tricuspid regurgitation and pulmonary stenosis. This results in **Right-Sided Heart Failure**, characterized by hepatomegaly, ascites, and peripheral edema. Therefore, stating it is "not a feature" is incorrect. **2. Analysis of other options:** * **Option A:** True. The hallmark is the deposition of **pearly, fibrous plaques** (composed of smooth muscle cells and collagen) on the endocardium. * **Option B:** True. Fibrous deposits occur primarily on the **ventricular aspect of the tricuspid valve** and the arterial aspect of the pulmonary valve. This leads to the "fixing" of the leaflets, causing regurgitation or stenosis. * **Option D:** True. Carcinoid heart disease is predominantly **right-sided**. The lungs act as a metabolic filter, inactivating serotonin before it reaches the left heart [1]. Left-sided lesions (mitral/aortic) are rare and usually only seen in patients with a patent foramen ovale (R-to-L shunt) or bronchial carcinoids. **High-Yield Clinical Pearls for NEET-PG:** * **Biomarker:** Urinary **5-HIAA** (5-hydroxyindoleacetic acid) levels correlate with the severity of heart disease. * **Pathognomonic Sign:** "TIPS" (Tricuspid Insufficiency, Pulmonary Stenosis) is the classic combination. * **Echocardiography:** The gold standard for diagnosis; shows thickened, retracted, and immobile valve leaflets. * **Treatment:** Somatostatin analogs (Octreotide) help symptoms, but definitive treatment for advanced heart failure is surgical valve replacement.

Question 86: Hypercalcemia is not seen in which of the following conditions?

A. Lithium therapy
B. Chronic renal failure
C. Multiple myeloma
D. Vitamin A deficiency (Correct Answer)

Explanation: The correct answer is **Vitamin A deficiency**. In fact, it is **Vitamin A toxicity (Hypervitaminosis A)** that causes hypercalcemia. High levels of Vitamin A stimulate osteoclast activity, leading to increased bone resorption and elevated serum calcium levels. **Analysis of Options:** * **Lithium therapy:** Lithium is a well-known cause of hypercalcemia [1]. It shifts the set-point of the calcium-sensing receptor (CaSR) in the parathyroid glands, requiring higher calcium levels to suppress Parathyroid Hormone (PTH) secretion. This results in **Hyperparathyroidism**. * **Chronic Renal Failure (CRF):** While early-stage CRF typically presents with hypocalcemia [2], long-standing disease leads to **Tertiary Hyperparathyroidism** [1]. In this state, the parathyroid glands become autonomous due to chronic overstimulation, leading to hypercalcemia. * **Multiple Myeloma:** This is a classic cause of hypercalcemia [1]. Myeloma cells produce Osteoclast Activating Factors (OAFs) like IL-6 and RANK-ligand, which cause extensive lytic bone lesions and release calcium into the bloodstream. **High-Yield Clinical Pearls for NEET-PG:** 1. **Vitamin D vs. Vitamin A:** Both cause hypercalcemia in toxicity, but via different mechanisms (Vitamin D increases intestinal absorption; Vitamin A increases bone resorption). 2. **Milk-Alkali Syndrome:** A triad of hypercalcemia, metabolic alkalosis, and renal failure due to excessive ingestion of calcium and absorbable antacids [1]. 3. **Thiazide Diuretics:** These cause hypercalcemia (by increasing renal calcium reabsorption) [1], whereas **Loop diuretics** (Furosemide) are used to treat it (by increasing calcium excretion). 4. **Granulomatous Diseases:** (e.g., Sarcoidosis, TB) cause hypercalcemia due to ectopic production of 1,25-dihydroxyvitamin D by macrophages [1].

Question 87: Which of the following is typically seen in the lipid profile of a patient with diabetes?

A. Decreased triglycerides
B. Increased HDL cholesterol
C. Increased LDL cholesterol (Correct Answer)
D. Decreased cholesterol

Explanation: **Explanation:** The characteristic pattern of dyslipidemia in Diabetes Mellitus (often termed **Diabetic Dyslipidemia**) is driven by insulin resistance and relative insulin deficiency. **Why Option C is Correct:** In diabetes, there is an increase in the flux of free fatty acids to the liver, leading to increased production of VLDL [1]. While the absolute level of LDL cholesterol may sometimes be normal, the **LDL particles are typically increased in number and are "small and dense" (Pattern B).** These small, dense LDL particles are highly atherogenic as they easily penetrate the arterial wall and are more susceptible to oxidation [1]. In clinical practice and exams, an elevated LDL-C level is a hallmark finding that necessitates statin therapy to reduce cardiovascular risk [2, 5]. **Analysis of Incorrect Options:** * **Option A (Decreased triglycerides):** Incorrect. Hypertriglyceridemia is the most common lipid abnormality in diabetes due to increased VLDL production and decreased clearance (reduced Lipoprotein Lipase activity). * **Option B (Increased HDL):** Incorrect. Low HDL cholesterol is a classic feature of diabetic dyslipidemia. Increased triglyceride levels lead to the exchange of TG for cholesterol in HDL particles, making them smaller and more easily cleared by the kidneys [1]. * **Option D (Decreased cholesterol):** Incorrect. Total cholesterol is generally elevated or remains high-normal due to the increase in VLDL and LDL fractions. **High-Yield NEET-PG Pearls:** 1. **The "Lipid Triad" of Diabetes:** High Triglycerides + Low HDL + Small, dense LDL particles [1]. 2. **Target Goal:** For diabetic patients with high CV risk, the target LDL is often <70 mg/dL (or even <55 mg/dL in very high risk). 3. **Drug of Choice:** Statins (HMG-CoA reductase inhibitors) are the first-line treatment for diabetic dyslipidemia [2].

Question 88: Which of the following conditions is not associated with diabetes mellitus?

A. Cushing syndrome
B. Acromegaly
C. Hypothyroidism (Correct Answer)
D. Pheochromocytoma

Explanation: ### Explanation The correct answer is **Hypothyroidism**. Diabetes mellitus (DM) is frequently associated with conditions that cause an excess of **counter-regulatory hormones** [1]. These hormones (cortisol, growth hormone, catecholamines, and glucagon) oppose the action of insulin, leading to increased gluconeogenesis and insulin resistance [3]. **1. Why Hypothyroidism is the correct answer:** Hypothyroidism is generally associated with a **decreased** rate of glucose absorption from the gut and a slower rate of insulin degradation. Unlike the other options, it does not cause hyperglycemia. In fact, in patients with pre-existing diabetes, the development of hypothyroidism may actually reduce insulin requirements and increase the risk of hypoglycemia. **2. Why the other options are incorrect:** * **Cushing Syndrome:** Characterized by excess **Cortisol**, which increases hepatic gluconeogenesis and decreases peripheral glucose uptake, leading to "Steroid Diabetes" [1], [3]. * **Acromegaly:** Characterized by excess **Growth Hormone (GH)**. GH is a potent insulin antagonist that promotes lipolysis and inhibits glucose utilization in muscles [1], [2]. * **Pheochromocytoma:** Characterized by excess **Catecholamines** (Epinephrine/Norepinephrine). These stimulate glycogenolysis and inhibit insulin secretion from pancreatic beta cells via alpha-2 adrenergic receptors [3], [4]. **Clinical Pearls for NEET-PG:** * **Secondary Diabetes:** This term refers to DM caused by other endocrine disorders (as listed above) or pancreatic diseases (e.g., Chronic Pancreatitis) [1]. * **Hyperthyroidism vs. Hypothyroidism:** While hypothyroidism doesn't cause DM, **Hyperthyroidism** can worsen glycemic control by increasing glucose absorption and promoting glycogenolysis [4]. * **Glucagonoma:** Another high-yield association; it presents with the "4Ds": Diabetes, Dermatitis (Necrolytic Migratory Erythema), Depression, and DVT.

Question 89: Which of the following is NOT a feature of diabetic nonproliferative retinopathy?

A. Neovascularization (Correct Answer)
B. Soft exudates
C. Microaneurysms
D. Intraretinal microvascular abnormalities (IRMA)

Explanation: Diabetic retinopathy is clinically categorized into two main stages: **Non-proliferative (NPDR)** and **Proliferative (PDR)**. The fundamental distinction lies in the presence of new blood vessel formation. [1] ### Why Neovascularization is the Correct Answer **Neovascularization** is the hallmark feature of **Proliferative Diabetic Retinopathy (PDR)**. It occurs when widespread retinal ischemia triggers the release of Vascular Endothelial Growth Factor (VEGF), leading to the growth of fragile, abnormal new vessels on the retina or optic disc. [1] Since the question asks for a feature NOT found in NPDR, neovascularization is the correct choice. ### Explanation of Incorrect Options (Features of NPDR) * **Microaneurysms:** These are the **earliest clinical sign** of diabetic retinopathy. They appear as small red dots due to focal outpouchings of retinal capillaries caused by pericyte loss. [1] * **Soft Exudates (Cotton Wool Spots):** These represent micro-infarctions of the nerve fiber layer. They are common in pre-proliferative (severe) NPDR. * **Intraretinal Microvascular Abnormalities (IRMA):** These are remodeled capillary beds that act as shunts between arterioles and venules. They are a key marker of **Severe NPDR** and indicate a high risk of progression to PDR. [1] ### High-Yield Clinical Pearls for NEET-PG * **Earliest Change:** Loss of pericytes (histological); Microaneurysms (clinical). * **Classification (Modified Airlie House):** NPDR is graded as Mild, Moderate, Severe, and Very Severe based on the "4-2-1 rule" (Hemorrhages in 4 quadrants, Venous beading in 2, or IRMA in 1). * **Macular Edema:** Can occur at **any stage** of diabetic retinopathy and is the most common cause of vision loss in NPDR. [1] * **Management:** Pan-retinal photocoagulation (PRP) is indicated for PDR, while Anti-VEGF agents are first-line for clinically significant macular edema. [1]

Question 90: Which statement is true regarding Familial Hypocalciuric Hypercalcemia?

A. It is inherited in an autosomal recessive pattern.
B. The cause is a defect in the PTH receptor.
C. Clinical symptoms typically manifest in the third decade of life.
D. Treatment is rarely necessary. (Correct Answer)

Explanation: **Explanation:** **Familial Hypocalciuric Hypercalcemia (FHH)** is a benign genetic disorder characterized by lifelong, stable elevations in serum calcium levels. 1. **Why Option D is correct:** In FHH, the body "resets" its calcium thermostat to a higher level. Despite the hypercalcemia, patients are typically **asymptomatic**, and the condition does not lead to the complications seen in primary hyperparathyroidism (like kidney stones or bone loss). Therefore, surgical or medical intervention is **rarely necessary**, and the primary goal is to avoid unnecessary parathyroidectomy. 2. **Why other options are incorrect:** * **Option A:** FHH is inherited in an **Autosomal Dominant** pattern. * **Option B:** The defect is in the **Calcium-Sensing Receptor (CaSR)**, not the PTH receptor [1]. This inactivating mutation makes the parathyroid glands and kidneys less sensitive to calcium, requiring higher levels to suppress PTH and promote urinary calcium excretion. * **Option C:** Hypercalcemia in FHH is present from **birth**. While it is often detected incidentally later in life, the biochemical abnormality is lifelong, unlike primary hyperparathyroidism which usually develops later [1]. **High-Yield Clinical Pearls for NEET-PG:** * **The "Low" Rule:** FHH is characterized by **Low** urinary calcium excretion (Urinary Calcium:Creatinine Clearance Ratio **<0.01**). * **PTH Levels:** PTH is typically **mildly elevated or inappropriately normal** despite high serum calcium [1]. * **Differential Diagnosis:** The most important task is distinguishing FHH from **Primary Hyperparathyroidism (PHPT)** [1]. In PHPT, the Ca:Cr clearance ratio is typically **>0.02**. * **Key takeaway:** If a patient has high calcium, low urine calcium, and a family history of hypercalcaemia—**do not operate.**

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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