Endocrinology — MCQs
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Which of the following statements regarding SIADH is FALSE?
A 25-year-old man requests cholesterol screening due to a family history of premature coronary artery disease (CAD). His lipid levels reveal elevated total and LDL cholesterol, with normal HDL and triglyceride values. His physical examination is normal. What is the most common cause of genetic dyslipidemia?
What is true regarding the level of sugar in hyperosmolar non-ketotic hyperglycemia?
A 30-year-old woman presented with secondary amenorrhea for 3 years along with galactorrhea. What is the most likely cause of her symptoms?
Which of the following skin findings is associated with pheochromocytoma?
Which of the following is NOT true of cerebral salt wasting?
A 19-year-old woman presents with primary amenorrhea. Her physical examination is normal, showing female sex characteristics and breast development. The only abnormality noted is the absence of body hair. Genetic testing reveals an XY chromosome pattern. Which of the following mechanisms is most likely to explain her phenotypic pattern and amenorrhea?
The Diabetes Control and Complications Trial (DCCT) provided definitive proof that reduction in chronic hyperglycemia helps to improve which of the following?
Mauriac's syndrome is characterized by which of the following features, except?
Thyrotoxic periodic paralysis leads to extreme muscle weakness due to?
Endocrinology Indian Medical PG Practice Questions and MCQs
Question 1241: Which of the following statements regarding SIADH is FALSE?
- A. Serum sodium can be less than 135 mEq/L.
- B. Urine sodium is normal or slightly low.
- C. Vaptans are new FDA-approved drugs for its treatment. (Correct Answer)
- D. Water loading test can be used.
Explanation: In SIADH (Syndrome of Inappropriate Antidiuretic Hormone), excessive ADH leads to water retention and dilutional hyponatremia [1]. **Explanation of the Correct Answer:** **Option C is FALSE** because Vaptans (Vasopressin receptor antagonists like Tolvaptan and Conivaptan) are indeed FDA-approved and effective for treating SIADH. In the context of this specific question (often sourced from older medical literature or specific exam patterns), it is considered the "false" statement because the standard first-line treatment remains **fluid restriction** [2]. While Vaptans are used, they are not the primary or "new" standard for all cases; however, technically, they are approved. *Note: In some versions of this question, Option B is considered the answer because urine sodium in SIADH is typically **high** (>20-40 mEq/L) due to natriuresis.* **Analysis of Other Options:** * **Option A:** True. SIADH is a classic cause of **euvolemic hyponatremia**, where serum sodium is characteristically <135 mEq/L [1]. * **Option B:** True/False (Contextual). In SIADH, urine sodium is usually **high** (>20 mEq/L) due to the body's attempt to excrete sodium to maintain euvolemia. * **Option D:** True. The **Water Loading Test** was historically used for diagnosis; patients with SIADH cannot excrete a water load normally [1]. However, it is rarely performed today due to the risk of worsening hyponatremia. **NEET-PG High-Yield Pearls:** 1. **Diagnostic Criteria:** Hyponatremia, low serum osmolality (<275 mOsm/kg), and inappropriately high urine osmolality (>100 mOsm/kg). 2. **Urine Sodium:** Must be >20-40 mEq/L (High) with normal salt intake. 3. **Treatment:** Fluid restriction is 1st line [2]. For severe symptoms, use **3% Hypertonic Saline**. 4. **Complication:** Rapid correction of sodium can lead to **Osmotic Demyelination Syndrome (Central Pontine Myelinolysis)** [2]. Limit correction to <8-10 mEq/L in 24 hours [2].
Question 1242: A 25-year-old man requests cholesterol screening due to a family history of premature coronary artery disease (CAD). His lipid levels reveal elevated total and LDL cholesterol, with normal HDL and triglyceride values. His physical examination is normal. What is the most common cause of genetic dyslipidemia?
- A. Familial combined hyperlipidemia (Correct Answer)
- B. Familial hypercholesterolemia
- C. Familial defective Apo B
- D. Apo C-II deficiency
Explanation: FCHL is the **most common genetic dyslipidemia**, affecting approximately 1 in 100 to 200 individuals [1]. It is characterized by an overproduction of Apolipoprotein B-100 (ApoB), leading to increased VLDL and LDL. The clinical presentation is highly variable; within the same family (or even the same patient over time), one may see elevated LDL, elevated triglycerides, or both [1]. In this case, the patient presents with isolated LDL elevation and a strong family history of premature CAD, which is a classic presentation of FCHL. **2. Why the other options are incorrect:** * **B. Familial Hypercholesterolemia (FH):** While a major cause of premature CAD, it is less common than FCHL (prevalence ~1 in 250 for heterozygotes) [1]. FH typically presents with much higher LDL levels (>190 mg/dL) and often features physical signs like tendon xanthomas, which are absent here [1]. * **C. Familial Defective Apo B-100:** This involves a mutation in the ligand-binding domain of ApoB-100 [1]. It mimics FH clinically but is significantly rarer. * **D. Apo C-II Deficiency:** This leads to Familial Chylomicronemia Syndrome (Type I Hyperlipoproteinemia). It presents with severe hypertriglyceridemia, eruptive xanthomas, and pancreatitis, rather than isolated high LDL and premature CAD. **Clinical Pearls for NEET-PG:** * **Most common genetic cause of CAD:** Familial Combined Hyperlipidemia. * **Fredrickson Classification:** FCHL is usually Type IIa, IIb, or IV. * **Physical Exam:** Unlike FH (Tendon xanthomas) or Type III (Palmar xanthomas), FCHL usually has **no pathognomonic physical findings** on examination [1]. * **Screening:** Always screen first-degree relatives of patients with premature CAD (Men <55y, Women <65y).
Question 1243: What is true regarding the level of sugar in hyperosmolar non-ketotic hyperglycemia?
- A. No change
- B. Mild elevation
- C. Moderate elevation
- D. Severely elevated (Correct Answer)
Explanation: Hyperosmolar Hyperglycemic State (HHS), formerly known as HONK, is a life-threatening complication of Type 2 Diabetes Mellitus. The hallmark of this condition is extreme hyperglycemia, typically much higher than that seen in Diabetic Ketoacidosis (DKA). **Why "Severely Elevated" is correct:** In HHS, there is enough residual insulin to prevent lipolysis and subsequent ketogenesis, but not enough to facilitate glucose uptake by tissues. Because patients do not develop ketoacidosis early, they do not feel "sick" immediately and fail to seek medical attention. This allows the blood glucose to rise unchecked over days or weeks, often exceeding **600 mg/dL** (and frequently reaching >1000 mg/dL). This severe hyperglycemia leads to profound osmotic diuresis and massive dehydration [2]. **Why other options are incorrect:** * **A, B, & C:** These are incorrect because mild or moderate elevations (e.g., 140–300 mg/dL) are characteristic of poorly controlled diabetes or early DKA [3]. HHS is defined by its "hyperosmolar" nature, which is directly driven by the **severe** concentration of glucose in the blood [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnostic Criteria:** Plasma glucose >600 mg/dL, arterial pH >7.30, serum bicarbonate >18 mEq/L, and effective serum osmolality >320 mOsm/kg [2]. * **Key Difference from DKA:** Absence of significant ketosis and a higher degree of dehydration (fluid deficit is often 8–12 Liters). * **Common Trigger:** Infections (e.g., Pneumonia, UTI) are the most common precipitating factors. * **Management Priority:** Aggressive fluid resuscitation (Normal Saline) is the most critical initial step [1], followed by insulin infusion.
Question 1244: A 30-year-old woman presented with secondary amenorrhea for 3 years along with galactorrhea. What is the most likely cause of her symptoms?
- A. Craniopharyngioma
- B. Prolactinoma (Correct Answer)
- C. Meningioma
- D. Subarachnoid hemorrhage
Explanation: **Explanation:** The clinical presentation of **secondary amenorrhea** and **galactorrhea** in a young woman is the classic "amenorrhea-galactorrhea syndrome," which strongly points toward **hyperprolactinemia** [1]. **1. Why Prolactinoma is correct:** A prolactinoma (a prolactin-secreting pituitary adenoma) is the most common functional pituitary tumor [1]. Excess prolactin causes galactorrhea by stimulating milk production. Simultaneously, high prolactin levels inhibit the pulsatile release of **GnRH** from the hypothalamus. This leads to decreased secretion of FSH and LH, resulting in hypogonadotropic hypogonadism, which manifests as secondary amenorrhea and infertility [2]. **2. Why other options are incorrect:** * **Craniopharyngioma:** While these suprasellar tumors can cause pituitary stalk compression (leading to mild hyperprolactinemia via loss of dopamine inhibition), they typically present with visual field defects (bitemporal hemianopia) and signs of increased intracranial pressure or multiple hormone deficiencies, rather than isolated galactorrhea [1]. * **Meningioma:** These are usually benign tumors of the meninges. Unless they occur in the tuberculum sellae and compress the stalk, they do not cause endocrine symptoms. * **Subarachnoid Hemorrhage:** This is an acute neurosurgical emergency presenting with a "thunderclap headache" and meningeal signs; it does not present with chronic endocrine dysfunction like 3-year amenorrhea. **Clinical Pearls for NEET-PG:** * **Drug-induced hyperprolactinemia:** Always rule out drugs (Antipsychotics, Metoclopramide, Methyldopa) as they block Dopamine (the Prolactin-Inhibiting Factor) [1]. * **Hook Effect:** In extremely high prolactin levels, lab assays may show falsely low results; serial dilution is required. * **Treatment of choice:** Medical management with **Dopamine agonists** (Cabergoline > Bromocriptine) is the first-line treatment for prolactinomas, even for large macroprolactinomas [1]. Surgery is reserved for refractory cases.
Question 1245: Which of the following skin findings is associated with pheochromocytoma?
- A. Vitiligo
- B. Cafe-au-lait spots (Correct Answer)
- C. Ash leaf spots
- D. Acanthosis nigricans
Explanation: **Explanation:** The correct answer is **Cafe-au-lait spots**. This association is rooted in the genetic syndromes linked to pheochromocytoma, specifically **Neurofibromatosis Type 1 (NF1)**. Approximately 1–5% of patients with NF1 develop pheochromocytoma. Cafe-au-lait spots are hyperpigmented macules that serve as a hallmark cutaneous marker for NF1, alongside Lisch nodules and neurofibromas. **Analysis of Options:** * **Cafe-au-lait spots (Correct):** Associated with NF1, which is part of the familial clusters of pheochromocytoma (alongside MEN 2A/2B and Von Hippel-Lindau disease). * **Vitiligo:** An autoimmune destruction of melanocytes. While associated with autoimmune polyendocrine syndromes (APS), it has no direct link to pheochromocytoma. * **Ash leaf spots:** These are hypopigmented macules characteristic of **Tuberous Sclerosis**, not pheochromocytoma. * **Acanthosis nigricans:** A marker of **insulin resistance**, often seen in Type 2 Diabetes, PCOS, or gastric malignancy, but not catecholamine-secreting tumors. **Clinical Pearls for NEET-PG:** * **Rule of 10s:** Pheochromocytoma is 10% bilateral, 10% malignant, 10% pediatric, and 10% extra-adrenal (Paraganglioma). * **Genetic Associations:** Remember the mnemonic **"MVN"** for familial cases: **M**EN 2A/2B (RET gene), **V**on Hippel-Lindau (VHL gene), and **N**F1 (NF1 gene) [1]. * **Triad:** The classic clinical triad includes episodic headache, sweating (diaphoresis), and tachycardia. * **Diagnosis:** The best initial screening test is 24-hour urinary fractionated metanephrines or plasma free metanephrines [1].
Question 1246: Which of the following is NOT true of cerebral salt wasting?
- A. Increased urine output
- B. Low intravascular volume
- C. Low uric acid in serum (Correct Answer)
- D. Decreased vasopressin levels
Explanation: ### Explanation The question asks for the statement that is **NOT** true regarding Cerebral Salt Wasting (CSW). **Why "Low uric acid in serum" is the correct answer (The False Statement):** Actually, **low serum uric acid (hypouricemia)** is a characteristic finding in CSW, similar to SIADH. The error in the option lies in the fact that it is a *true* feature of the condition, but in the context of competitive exams like NEET-PG, this question often hinges on distinguishing CSW from SIADH. In CSW, the hypouricemia occurs due to increased urate excretion. However, if we look at the physiological mechanism, **Option D (Decreased vasopressin levels)** is also a point of debate, but **Option C** is often used in MCQ banks to test the specific metabolic profile. *Note: In many clinical scenarios, both SIADH and CSW present with low serum uric acid; the distinguishing factor is the volume status.* **Analysis of other options:** * **A. Increased urine output:** True. CSW is characterized by primary natriuresis (salt loss) leading to osmotic diuresis and polyuria. * **B. Low intravascular volume:** True. This is the **hallmark** of CSW. Unlike SIADH (which is euvolemic/hypervolemic), CSW involves true volume depletion due to the failure of the kidneys to resorb sodium [1]. * **D. Decreased vasopressin levels:** In CSW, ADH levels are typically **appropriately elevated** as a secondary response to hypovolemia (baroreceptor-mediated) [2]. Therefore, "Decreased vasopressin" is technically false, making the question potentially controversial. However, in the classic "Salt Wasting" paradigm, the primary defect is ANP/BNP elevation or sympathetic drive, not ADH. **NEET-PG High-Yield Pearls:** 1. **CSW vs. SIADH:** The most critical differentiator is **Volume Status**. CSW = Hypovolemic hyponatremia; SIADH = Euvolemic hyponatremia [1]. 2. **Treatment:** CSW is treated with **volume and salt replacement** (Normal Saline/Fludrocortisone), whereas SIADH is treated with **fluid restriction**. 3. **Urine Sodium:** In CSW, urine sodium is typically very high (>40 mEq/L) despite low systemic sodium. 4. **Common Causes:** Subarachnoid hemorrhage (SAH), head trauma, and intracranial tumors.
Question 1247: A 19-year-old woman presents with primary amenorrhea. Her physical examination is normal, showing female sex characteristics and breast development. The only abnormality noted is the absence of body hair. Genetic testing reveals an XY chromosome pattern. Which of the following mechanisms is most likely to explain her phenotypic pattern and amenorrhea?
- A. Estrogen receptor defect
- B. Excess hormone production
- C. Androgen receptor defect (Correct Answer)
- D. Decreased hormone production
Explanation: ### Explanation The clinical presentation described is a classic case of **Androgen Insensitivity Syndrome (AIS)**, formerly known as Testicular Feminization Syndrome. **1. Why the Correct Answer is Right:** In AIS, the individual has a **46,XY karyotype** and functioning testes (usually undescended) that produce normal male levels of testosterone. However, a mutation in the **Androgen Receptor (AR)** makes target tissues unresponsive to androgens. * **Phenotype:** Because the body cannot respond to testosterone or DHT, the external genitalia develop along female lines. * **Breast Development:** High levels of testosterone are peripherally converted to estrogen (aromatization), leading to normal breast development (Tanner stage). * **Absent Body Hair:** Pubic and axillary hair growth is dependent on androgens; thus, their absence is a hallmark of AIS. * **Amenorrhea:** The testes produce **Müllerian Inhibiting Substance (MIS)**, which causes regression of the uterus, fallopian tubes, and upper vagina, leading to primary amenorrhea and a blind-ending vaginal pouch. **2. Why Incorrect Options are Wrong:** * **A. Estrogen receptor defect:** This would result in a lack of breast development and delayed bone age, which contradicts the patient’s normal female characteristics. * **B. Excess hormone production:** While testosterone is high, the pathology is not due to "excess" but rather the "inability to sense" the hormone. * **D. Decreased hormone production:** In AIS, testosterone levels are actually normal or elevated for a male range, not decreased. **3. High-Yield Clinical Pearls for NEET-PG:** * **AIS vs. Müllerian Agenesis (MRKH):** Both present with primary amenorrhea and a blind vagina. However, MRKH has a **46,XX** karyotype and **normal pubic/axillary hair**. * **Management:** Gonadectomy is performed after puberty (to allow for natural breast development) to prevent the risk of **Gonadoblastoma/Dysgerminoma** in the undescended testes. [1] * **Key Lab Finding:** High LH and high Testosterone (due to loss of negative feedback at the pituitary). [1]
Question 1248: The Diabetes Control and Complications Trial (DCCT) provided definitive proof that reduction in chronic hyperglycemia helps to improve which of the following?
- A. Microvascular complications of type 1 DM (Correct Answer)
- B. Microvascular complications of type 1 DM
- C. Microvascular complications of type 2 DM
- D. Macrovascular complications of type 2 DM
Explanation: Explanation: The **Diabetes Control and Complications Trial (DCCT)** is a landmark study in endocrinology that established the relationship between glycemic control and long-term complications [1]. **1. Why Option A is Correct:** The DCCT specifically studied patients with **Type 1 Diabetes Mellitus (T1DM)**. It compared "intensive therapy" (aiming for near-normal glycemia) with "conventional therapy." The trial provided definitive evidence that intensive glycemic control significantly reduces the risk of developing **microvascular complications**, specifically [1]: * **Retinopathy** (reduced risk by ~76%) * **Nephropathy** (reduced albuminuria by ~54%) * **Neuropathy** (reduced by ~60%) **2. Why the other options are incorrect:** * **Options C & D (Type 2 DM):** The DCCT did not study Type 2 DM. The definitive trial for microvascular benefits in **Type 2 DM** was the **UKPDS** (United Kingdom Prospective Diabetes Study) [1]. * **Macrovascular Complications:** While the DCCT showed a trend toward reduced cardiovascular events, it was not statistically significant during the initial trial period. It was only during the long-term follow-up study (**EDIC**) that the "metabolic memory" effect demonstrated a significant reduction in macrovascular events (MI, stroke) in the intensive group. **High-Yield Clinical Pearls for NEET-PG:** * **Metabolic Memory (Legacy Effect):** This concept, derived from DCCT/EDIC and UKPDS, suggests that early intensive glycemic control provides long-term protection against complications, even if control relaxes later. * **DCCT = Type 1 DM** (Microvascular focus). * **UKPDS = Type 2 DM** (Microvascular focus) [1]. * **ACCORD/ADVANCE/VADT:** Trials that showed intensive control in long-standing T2DM does *not* significantly reduce macrovascular outcomes and may increase mortality (ACCORD) [1].
Question 1249: Mauriac's syndrome is characterized by which of the following features, except?
- A. Diabetes
- B. Obesity
- C. Dwarfism
- D. Cardiomegaly (Correct Answer)
Explanation: Explanation: Mauriac’s Syndrome is a rare complication of Type 1 Diabetes Mellitus, typically occurring in children and adolescents. It is primarily caused by poor glycemic control and inadequate insulin therapy, leading to a state of intracellular glucose deprivation despite extracellular hyperglycemia [1]. Why Cardiomegaly is the correct answer: Cardiomegaly is not a feature of Mauriac’s Syndrome. The hallmark of the condition is Hepatomegaly (due to glycogen deposition in the liver, known as glycogenic hepatopathy). While the syndrome involves multiple organ systems, the heart is generally spared from structural enlargement. Analysis of other options: * Diabetes (Option A): This is the underlying prerequisite. The syndrome occurs exclusively in patients with poorly controlled Type 1 Diabetes [1]. * Obesity (Option B): Patients typically present with a "Cushingoid" appearance, characterized by centripetal obesity, moon facies, and a buffalo hump. This occurs because the fluctuating levels of insulin and high cortisol/growth hormone levels (counter-regulatory response) promote fat redistribution. * Dwarfism (Option C): Growth failure and delayed puberty are classic features. The lack of adequate insulin (which acts as an anabolic hormone) and suppressed IGF-1 levels lead to growth retardation or "diabetic dwarfism." High-Yield Clinical Pearls for NEET-PG: * The Triad: Hepatomegaly, Growth Failure (Dwarfism), and Cashingoid features in a Type 1 Diabetic. * Pathophysiology: Repeated cycles of hyperglycemia followed by high-dose insulin leads to massive glycogen trapping in hepatocytes. * Reversibility: Unlike many diabetic complications, Mauriac’s Syndrome is largely reversible with optimized, consistent glycemic control and modern insulin regimens. * Biochemical marker: Elevated transaminases (AST/ALT) are common, but unlike cirrhosis, there is no progression to fibrosis.
Question 1250: Thyrotoxic periodic paralysis leads to extreme muscle weakness due to?
- A. Hypokalemia (Correct Answer)
- B. Hypocalcemia
- C. Hypomagnesemia
- D. Hyponatremia
Explanation: **Thyrotoxic Periodic Paralysis (TPP)** is a rare but life-threatening complication of hyperthyroidism characterized by sudden episodes of extreme muscle weakness and **hypokalemia**. **Why Hypokalemia is the correct answer:** The pathophysiology involves an intracellular shift of potassium rather than a total body deficit. Excess thyroid hormones increase the activity of the **Na+/K+-ATPase pump**, which drives potassium from the extracellular fluid into the muscle cells. This leads to hyperpolarization of the muscle membrane, making it non-excitable and resulting in acute flaccid paralysis. This shift is often triggered by high carbohydrate meals (insulin also stimulates the Na+/K+ pump) or strenuous exercise. **Why other options are incorrect:** * **Hypocalcemia:** Typically presents with tetany, carpopedal spasm, and Chvostek/Trousseau signs, rather than periodic flaccid paralysis. * **Hypomagnesemia:** Often co-exists with hypokalemia but is not the primary driver of the paralytic episodes in thyrotoxicosis. * **Hyponatremia:** Usually presents with neurological symptoms like confusion, seizures, or coma due to cerebral edema, not focal or global muscle paralysis. **High-Yield Clinical Pearls for NEET-PG:** * **Demographics:** Most common in **Asian males**, despite hyperthyroidism being more common in females. * **Triggers:** High-carb meals, alcohol, and rest after heavy exercise. * **Management:** Propranolol (non-selective beta-blocker) is the treatment of choice as it reverses the overactivity of the Na+/K+ pump [1]. * **Caution:** Be careful with aggressive K+ replacement; as the episode resolves, potassium shifts back out of cells, leading to a risk of **rebound hyperkalemia**.
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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