Endocrinology — MCQs

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 231: Which of the following variants of congenital adrenal hyperplasia (CAH) presents with mineralocorticoid deficiency?

A. 11-beta-hydroxylase deficiency
B. 17-alpha-hydroxylase deficiency
C. P450 oxidoreductase deficiency
D. 3-beta-hydroxysteroid dehydrogenase deficiency (Correct Answer)

Explanation: ### Explanation **1. Why Option D is Correct:** In **3-beta-hydroxysteroid dehydrogenase (3β-HSD) deficiency**, there is a block in the conversion of Pregnenolone to Progesterone and 17-OH Pregnenolone to 17-OH Progesterone. This enzyme is essential for the synthesis of **all three classes** of adrenal steroids: mineralocorticoids, glucocorticoids, and sex steroids. Because the block occurs very early in the steroidogenesis pathway, the production of Aldosterone is severely impaired, leading to **mineralocorticoid deficiency** (salt-wasting, hyponatremia, and hyperkalemia). **2. Why the Other Options are Incorrect:** * **A. 11-beta-hydroxylase deficiency:** This block leads to an accumulation of **11-deoxycorticosterone (DOC)**. DOC is a potent mineralocorticoid; its excess causes hypertension and hypokalemia, rather than deficiency. * **B. 17-alpha-hydroxylase deficiency:** This variant results in a shunting of precursors toward the mineralocorticoid pathway. There is an overproduction of **Corticosterone and DOC**, leading to hypertension and hypokalemia. * **C. P450 oxidoreductase deficiency:** This is a complex "mixed" deficiency. While it can affect various enzymes, it typically presents with apparent mineralocorticoid excess or normal levels, rather than a primary salt-wasting mineralocorticoid deficiency. **3. Clinical Pearls for NEET-PG:** * **Salt-Wasting CAH:** Only 21-hydroxylase (75% of cases) and 3β-HSD deficiency typically present with salt-wasting (mineralocorticoid deficiency). * **Hypertension in CAH:** Think of the "1"s. If the enzyme starts with **1** (**1**1-β or **1**7-α), the patient will have hypertension due to mineralocorticoid excess. * **Virilization:** 3β-HSD deficiency is unique because it causes **ambiguous genitalia in both sexes** (mild virilization in females due to DHEA; undervirilization in males due to lack of potent testosterone).

Question 232: Which of the following is NOT true about congenital adrenal hyperplasia?

A. It is an autosomal recessive disorder.
B. 21-Hydroxylase deficiency is the most common form. (Correct Answer)
C. It is a common cause of genital ambiguity at birth.
D. Hypoglycemia can be seen in affected individuals.

Explanation: **Explanation** Congenital Adrenal Hyperplasia (CAH) is a group of inherited disorders characterized by enzyme defects in the steroidogenesis pathway. **Why Option B is the "Correct" Answer (The Exception):** The question asks for the statement that is **NOT** true. However, Option B states that "21-Hydroxylase deficiency is the most common form," which is a **factually true statement** (accounting for >90% of cases). In the context of a "Which is NOT true" question, if Option B is marked as the answer, it implies a technical error in the question stem or options provided. *Note: In standard medical literature, all four options (A, B, C, and D) are actually true statements regarding CAH.* **Analysis of Other Options:** * **Option A (True):** CAH follows an **autosomal recessive** inheritance pattern. * **Option C (True):** It is the **most common cause of ambiguous genitalia** (female pseudohermaphroditism) in a newborn with a 46,XX karyotype due to excess androgen production. * **Option D (True):** **Hypoglycemia** occurs because cortisol deficiency leads to impaired gluconeogenesis and increased insulin sensitivity. **NEET-PG High-Yield Pearls:** 1. **21-Hydroxylase Deficiency:** Most common; presents with low cortisol/aldosterone and **high 17-OH Progesterone**. Results in salt-wasting (hyponatremia, hyperkalemia) and virilization. 2. **11β-Hydroxylase Deficiency:** Presents with **hypertension** (due to 11-deoxycorticosterone buildup) and virilization. 3. **17α-Hydroxylase Deficiency:** Presents with hypertension but **delayed puberty/sexual infantilism** (low sex steroids). 4. **Gold Standard Diagnosis:** ACTH stimulation test. 5. **Treatment:** Glucocorticoid (Hydrocortisone) to suppress ACTH and Fludrocortisone for salt-wasting forms.

Question 233: What is the commonest feature of hypothyroidism in children?

A. Cataract
B. Recurrent seizures
C. Cold extremities (Correct Answer)
D. Laryngospasms

Explanation: **Explanation:** Hypothyroidism, whether congenital or acquired, leads to a generalized slowing of metabolic processes. Thyroid hormones are essential for thermogenesis and maintaining the basal metabolic rate (BMR). **1. Why "Cold Extremities" is correct:** In hypothyroidism, the reduction in metabolic heat production leads to peripheral vasoconstriction as the body attempts to conserve core temperature. This results in **cold extremities** and **cold intolerance**, which are among the most common and earliest clinical signs. Other frequent features include lethargy, constipation, bradycardia, and dry skin. **2. Why the other options are incorrect:** * **A. Cataract:** This is not a feature of hypothyroidism. However, it is a classic finding in **Hypoparathyroidism** (due to chronic hypocalcemia) and **Galactosemia**. * **B. Recurrent Seizures:** While severe hypothyroidism (Myxedema coma) can cause mental status changes, recurrent seizures are not a standard feature. Seizures are more characteristic of **Hypocalcemia** (often seen in hypoparathyroidism) or hypoglycemia. * **D. Laryngospasms:** This is a specific sign of neuromuscular irritability caused by **Hypocalcemia** (Tetany), not hypothyroidism. **Clinical Pearls for NEET-PG:** * **Most common cause of Congenital Hypothyroidism:** Thyroid dysgenesis (Ectopy is the most common specific type). * **Most common cause of Acquired Hypothyroidism:** Hashimoto’s thyroiditis. * **Early Sign in Neonates:** Prolonged physiological jaundice and a large posterior fontanelle (>0.5 cm). * **Key Growth Finding:** The most sensitive clinical indicator of hypothyroidism in children is a **decrease in growth velocity** leading to short stature with delayed bone age.

Question 234: A newborn baby presents with shock, hyperkalemia, and hypoglycemia. What is the most likely diagnosis?

A. Septicemia
B. Inborn error of metabolism
C. Diabetes mellitus
D. Congenital adrenal hyperplasia (Correct Answer)

Explanation: **Explanation:** The clinical triad of **shock, hyperkalemia, and hypoglycemia** in a newborn is a classic presentation of an **Adrenal Crisis**, most commonly caused by **Congenital Adrenal Hyperplasia (CAH)**. **Why CAH is the correct answer:** The most common form of CAH is **21-hydroxylase deficiency**. This enzyme defect leads to: 1. **Mineralocorticoid deficiency (Aldosterone):** Causes "salt-wasting," resulting in hyponatremia, **hyperkalemia**, and dehydration leading to hypovolemic **shock**. 2. **Glucocorticoid deficiency (Cortisol):** Leads to impaired gluconeogenesis, resulting in **hypoglycemia** and poor stress response. 3. **Androgen excess:** May cause ambiguous genitalia in females (though males may appear normal initially). **Why other options are incorrect:** * **Septicemia:** While it causes shock and hypoglycemia, it typically presents with a normal or low potassium level (unless complicated by acute renal failure). * **Inborn Error of Metabolism (IEM):** Many IEMs cause hypoglycemia and metabolic acidosis, but they rarely present with the specific electrolyte pattern of hyperkalemia and hyponatremia seen in adrenal insufficiency. * **Diabetes Mellitus:** Neonatal diabetes presents with hyperglycemia and dehydration, not hypoglycemia. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Elevated levels of **17-hydroxyprogesterone (17-OHP)**. * **Electrolyte Hallmark:** Hyponatremia + Hyperkalemia + Metabolic Acidosis. * **Immediate Management:** Aggressive fluid resuscitation (Normal Saline) and IV Hydrocortisone. * **Karyotyping:** Essential in female infants with ambiguous genitalia to confirm 46,XX.

Question 235: An 8-year-old girl presents with symptoms of rickets. Laboratory investigations reveal Serum Calcium 7.2 mg/dL, Serum Phosphates 2.3 mg/dL, and Alkaline Phosphatase 2420 IU/L. What is the most probable diagnosis?

A. Vitamin D-dependent rickets type II
B. Hypophosphatemic rickets
C. Nutritional rickets (Correct Answer)
D. Secondary hyperparathyroidism

Explanation: ### Explanation **Correct Answer: C. Nutritional rickets** The clinical and biochemical profile points towards **Nutritional Vitamin D Deficiency Rickets**. In this condition, the primary pathology is a deficiency of Vitamin D, leading to decreased intestinal absorption of calcium and phosphorus. 1. **Low Serum Calcium (7.2 mg/dL):** This is the hallmark of nutritional rickets. Low calcium triggers a compensatory rise in Parathyroid Hormone (Secondary Hyperparathyroidism). 2. **Low Serum Phosphate (2.3 mg/dL):** Elevated PTH causes phosphaturia (renal loss of phosphate), leading to hypophosphatemia. 3. **Markedly Elevated Alkaline Phosphatase (2420 IU/L):** This reflects increased osteoblastic activity and is a sensitive marker for the severity and activity of rickets. --- ### Why other options are incorrect: * **Hypophosphatemic Rickets (X-linked):** The primary defect is renal phosphate wasting. Characteristically, **Serum Calcium is normal**, while phosphate is low. * **Vitamin D-dependent rickets (VDDR) Type II:** While biochemical markers are similar (low Ca, low PO4), this is a rare genetic resistance to Vitamin D. It is usually associated with **alopecia**, which is not mentioned here. * **Secondary Hyperparathyroidism:** This is a *physiological response* to low calcium (seen in nutritional rickets or CKD), not a primary diagnosis for rickets in this context. --- ### High-Yield Clinical Pearls for NEET-PG: * **Earliest Radiological Sign:** Cupping and splaying of the metaphysis (best seen at the distal radius/ulna). * **Earliest Biochemical Change:** Decreased Serum Phosphorus (due to early PTH rise). * **Most Sensitive Marker of Healing:** Falling levels of Alkaline Phosphatase. * **Vitamin D Levels:** In nutritional rickets, 25(OH)D levels are low, whereas in VDDR Type II, 1,25(OH)₂D levels are actually elevated due to receptor resistance.

Question 236: Reilly bodies are seen in which of the following conditions?

A. Gangliosidosis
B. Behcet's disease
C. Gaucher's disease
D. Hurler disease (Correct Answer)

Explanation: **Explanation:** **Reilly bodies** (also known as Alder-Reilly anomalies) are large, coarse, dark-staining granules found in the cytoplasm of leukocytes (neutrophils, monocytes, and lymphocytes). These granules represent partially degraded **mucopolysaccharides** (glycosaminoglycans) stored within lysosomes. 1. **Why Hurler Disease is Correct:** Hurler disease (Mucopolysaccharidosis Type I) is the classic condition associated with Reilly bodies. Due to a deficiency of the enzyme **alpha-L-iduronidase**, dermatan sulfate and heparan sulfate accumulate in various tissues. When these substances accumulate in white blood cells, they appear as dense, azurophilic granules (Reilly bodies) on a peripheral blood smear stained with Wright-Giemsa. 2. **Analysis of Incorrect Options:** * **Gangliosidosis:** While this is a lysosomal storage disorder, it is characterized by the accumulation of lipids (gangliosides) rather than mucopolysaccharides. It typically presents with cherry-red spots and neurodegeneration but not Reilly bodies. * **Behcet’s Disease:** This is a multisystem inflammatory vasculitis characterized by oral/genital ulcers and uveitis. It is not a storage disorder and does not feature these cytoplasmic inclusions. * **Gaucher’s Disease:** This is a lipid storage disease (glucocerebrosidase deficiency). The characteristic finding is the **Gaucher cell** (macrophages with a "wrinkled tissue paper" appearance), not Reilly bodies. **High-Yield Clinical Pearls for NEET-PG:** * **Alder-Reilly Anomaly:** Can be seen in all Mucopolysaccharidoses (MPS I to VII), but Hurler (MPS I) and Hunter (MPS II) are the most common associations. * **Differential Diagnosis:** Reilly bodies can resemble the toxic granulation seen in severe infections; however, Reilly bodies are present in all leukocytes and occur regardless of infection. * **Hurler Syndrome Key Features:** Corneal clouding, coarse facial features (gargoylism), hepatosplenomegaly, and dysostosis multiplex.

Question 237: Short stature secondary to growth hormone deficiency is associated with which of the following?

A. Normal body proportions (Correct Answer)
B. Low birth weight
C. Normal epiphyseal development
D. Height age equal to skeletal age

Explanation: **Explanation:** Short stature in children is broadly classified into **proportionate** and **disproportionate** types. Growth Hormone Deficiency (GHD) is a classic cause of **proportionate short stature**. **1. Why Option A is Correct:** Growth hormone (GH) is essential for linear bone growth but does not interfere with the structural development of the skeleton. In GHD, there is a symmetrical reduction in the growth of all segments (limbs and trunk). Therefore, the upper segment to lower segment (US:LS) ratio and arm span remain appropriate for the child's chronological age, resulting in **normal body proportions**. **2. Why Other Options are Incorrect:** * **Option B (Low birth weight):** Infants with isolated GHD typically have **normal birth weight and length** because intrauterine growth is largely independent of fetal GH (it is driven by IGF-2 and maternal factors). Growth failure usually becomes evident after 6–12 months of age. * **Option C (Normal epiphyseal development):** GH is necessary for chondrocyte proliferation at the epiphyseal plate. Deficiency leads to **delayed epiphyseal appearance** and delayed bone maturation. * **Option D (Height age equal to skeletal age):** In GHD, the **Skeletal Age (Bone Age) is typically more delayed** than the Height Age (Bone Age < Height Age < Chronological Age). This delay is what allows these children to potentially respond to GH therapy. **Clinical Pearls for NEET-PG:** * **Physical Findings:** "Cherubic" appearance (doll-like facies), truncal obesity, high-pitched voice, and microphallus (if associated with gonadotropin deficiency). * **Screening:** Low IGF-1 and IGFBP-3 levels. * **Gold Standard Diagnosis:** GH stimulation test (e.g., using insulin, arginine, or clonidine) showing a peak GH level <10 ng/mL. * **Laron Syndrome:** A condition of GH insensitivity where GH levels are actually high, but IGF-1 is low.

Question 238: Monogenic transmission of diabetes mellitus occurs in which of the following conditions?

A. Insulin Dependent Diabetes Mellitus (IDDM)
B. Non-insulin Dependent Diabetes Mellitus (NIDDM)
C. Latent Autoimmune Diabetes in Adults (LADA)
D. Maturity Onset Diabetes of the Young (MODY) (Correct Answer)

Explanation: **Explanation:** The correct answer is **Maturity Onset Diabetes of the Young (MODY)**. **1. Why MODY is correct:** MODY is a classic example of **monogenic diabetes**, meaning it is caused by a mutation in a **single gene**. It follows an **autosomal dominant** inheritance pattern. Unlike Type 1 or Type 2 diabetes, which are polygenic (involving multiple genes and environmental factors), MODY results from primary defects in beta-cell function. The most common subtypes involve mutations in the *HNF1A* gene (MODY 3) and the *Glucokinase* gene (MODY 2). **2. Why other options are incorrect:** * **IDDM (Type 1 DM):** This is a **polygenic** autoimmune disorder. While there is a genetic predisposition (associated with HLA-DR3 and DR4), it requires environmental triggers and involves the destruction of beta cells by multiple antibodies. * **NIDDM (Type 2 DM):** This is also **polygenic** and multifactorial. It involves a complex interplay between numerous susceptibility genes, insulin resistance, and lifestyle factors (obesity). * **LADA:** Often called "Type 1.5 diabetes," LADA is an autoimmune form of diabetes in adults. Like Type 1 DM, it is **polygenic** and characterized by the presence of autoantibodies (e.g., anti-GAD). **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad of MODY:** (1) Early onset (usually <25 years), (2) Non-ketotic diabetes, and (3) Autosomal dominant family history (3 generations). * **MODY 2 (Glucokinase mutation):** Usually presents with mild, stable fasting hyperglycemia; often requires no treatment except during pregnancy. * **MODY 3 (HNF1A):** The most common form; these patients are highly sensitive to **Sulfonylureas**. * **Neonatal Diabetes:** Another monogenic form (presents <6 months of age), often due to *KCNJ11* mutations.

Question 239: A child presents with hepatosplenomegaly, abdominal distension, jaundice, anemia, and adrenal calcification. Which of the following is the diagnosis?

A. Adrenal hemorrhage
B. Pheochromocytoma
C. Wolman's disease (Correct Answer)
D. Addison's disease

Explanation: ### Explanation **Correct Answer: C. Wolman's Disease** **Understanding the Concept:** Wolman’s disease is a rare, autosomal recessive lysosomal storage disorder caused by a deficiency of the enzyme **Lysosomal Acid Lipase (LAL)**. This deficiency leads to the massive accumulation of cholesteryl esters and triglycerides in various organs. * **Hepatomegaly & Jaundice:** Lipid accumulation in the liver leads to progressive cirrhosis and liver failure. * **Splenomegaly & Anemia:** Infiltration of the spleen and bone marrow results in organomegaly and cytopenias. * **Adrenal Calcification:** This is the **pathognomonic hallmark** of Wolman’s disease. Lipid deposits in the adrenal cortex undergo necrosis and subsequent calcification, often visible on X-ray or CT. This leads to primary adrenal insufficiency. **Why Other Options are Incorrect:** * **A. Adrenal Hemorrhage:** While it can cause adrenal calcification (usually unilateral and curvilinear), it typically presents in the neonatal period following birth trauma or sepsis (Waterhouse-Friderichsen syndrome) and does not explain the massive hepatosplenomegaly. * **B. Pheochromocytoma:** This is a catecholamine-secreting tumor presenting with hypertension, palpitations, and sweating. It does not cause diffuse storage symptoms or diffuse adrenal calcification. * **C. Addison’s Disease:** This is a clinical state of adrenal insufficiency. While Wolman’s causes Addisonian features, "Addison’s disease" itself is a broad diagnosis and does not account for the systemic storage symptoms (hepatosplenomegaly/jaundice). **NEET-PG High-Yield Pearls:** * **Enzyme Defect:** Lysosomal Acid Lipase (LAL). * **Radiology:** Bilateral, enlarged, "bell-shaped" or "stippled" adrenal calcifications. * **Clinical Course:** Usually fatal within the first year of life due to malabsorption (steatorrhea) and liver failure. * **Adult Form:** A milder, late-onset version of LAL deficiency is known as **Cholesteryl Ester Storage Disease (CESD)**, which usually lacks the prominent adrenal calcification seen in Wolman’s.

Question 240: A 6-month-old baby presents to the emergency department with features of cardiac failure. On examination, developmental delay and a large tongue are noted. Echocardiography reveals severe concentric left ventricular hypertrophy. What is the most probable diagnosis?

A. Pompe disease (Correct Answer)
B. Von Gierke's disease
C. Forbes disease
D. McArdle's disease

Explanation: **Explanation:** The clinical triad of **infantile-onset heart failure**, **severe concentric left ventricular hypertrophy (LVH)**, and **macroglossia** (large tongue) in a 6-month-old is classic for **Pompe Disease (Glycogen Storage Disease Type II)**. **Why Pompe Disease is Correct:** Pompe disease is caused by a deficiency of the lysosomal enzyme **acid alpha-glucosidase (acid maltase)**. Unlike other GSDs, glycogen accumulates within lysosomes in various tissues, most notably the **cardiac and skeletal muscles**. This leads to massive cardiomegaly (often described as a "globular heart" on X-ray), hypertrophic cardiomyopathy, and profound hypotonia ("floppy baby"). The macroglossia and developmental delay further support this diagnosis. **Why Other Options are Incorrect:** * **Von Gierke’s Disease (GSD Type I):** Primarily affects the liver and kidneys. It presents with severe hypoglycemia, hepatomegaly, and "doll-like" facies, but **never involves the heart**. * **Forbes/Cori Disease (GSD Type III):** Caused by debranching enzyme deficiency. While it can occasionally involve the heart, it typically presents with hepatomegaly and growth retardation; the cardiac involvement is never as severe or early-onset as in Pompe. * **McArdle’s Disease (GSD Type V):** A muscle phosphorylase deficiency that presents in **adolescence or adulthood** with exercise-induced cramps and myoglobinuria. It does not cause infantile heart failure. **High-Yield Clinical Pearls for NEET-PG:** * **ECG Finding:** Pompe disease characteristically shows **short PR intervals** and **giant QRS complexes** (due to massive hypertrophy). * **Enzyme:** Acid Alpha-Glucosidase (Acid Maltase). * **Stain:** Periodic Acid-Schiff (PAS) positive vacuoles in muscle biopsy. * **Treatment:** Enzyme Replacement Therapy (ERT) with Alglucosidase alfa.

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Disorders of Growth

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Thyroid Disorders

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Disorders of Puberty

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Adrenal Disorders

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Diabetes Mellitus in Children

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Disorders of Calcium and Phosphate Metabolism

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Disorders of Sexual Development

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Hypoglycemia

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Obesity and Metabolic Syndrome

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Pituitary Disorders

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Multiple Endocrine Neoplasia Syndromes

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Endocrine Emergencies

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