Endocrinology Practice Questions

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

3-beta-hydroxysteroid dehydrogenase deficiency. ### 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).

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

21-Hydroxylase deficiency is the most common form.. **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.

Q: What is the commonest feature of hypothyroidism in children?

Cold extremities. **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.

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

Congenital adrenal hyperplasia. **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.

Q: 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?

Nutritional rickets. ### 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.

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

Normal body proportions. **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.

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

Maturity Onset Diabetes of the Young (MODY). **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.

Q: 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?

Pompe disease. **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.

Question 1

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

Accepted Answer

3-beta-hydroxysteroid dehydrogenase deficiency

Answer

11-beta-hydroxylase deficiency

Answer

17-alpha-hydroxylase deficiency

Answer

P450 oxidoreductase deficiency

Question 2

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

Accepted Answer

21-Hydroxylase deficiency is the most common form.

Answer

It is an autosomal recessive disorder.

Answer

It is a common cause of genital ambiguity at birth.

Answer

Hypoglycemia can be seen in affected individuals.

Question 3

What is the commonest feature of hypothyroidism in children?

Accepted Answer

Cold extremities

Answer

Cataract

Answer

Recurrent seizures

Answer

Laryngospasms

Question 4

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

Accepted Answer

Congenital adrenal hyperplasia

Answer

Septicemia

Answer

Inborn error of metabolism

Answer

Diabetes mellitus

Question 5

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?

Accepted Answer

Nutritional rickets

Answer

Vitamin D-dependent rickets type II

Answer

Hypophosphatemic rickets

Answer

Secondary hyperparathyroidism

Question 6

Reilly bodies are seen in which of the following conditions?

Accepted Answer

Hurler disease

Answer

Gangliosidosis

Answer

Behcet's disease

Answer

Gaucher's disease

Question 7

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

Accepted Answer

Normal body proportions

Answer

Low birth weight

Answer

Normal epiphyseal development

Answer

Height age equal to skeletal age

Question 8

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

Accepted Answer

Maturity Onset Diabetes of the Young (MODY)

Answer

Insulin Dependent Diabetes Mellitus (IDDM)

Answer

Non-insulin Dependent Diabetes Mellitus (NIDDM)

Answer

Latent Autoimmune Diabetes in Adults (LADA)

Question 9

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

Accepted Answer

Wolman's disease

Answer

Adrenal hemorrhage

Answer

Pheochromocytoma

Answer

Addison's disease

Question 10

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?

Accepted Answer

Pompe disease

Answer

Von Gierke's disease

Answer

Forbes disease

Answer

McArdle's disease

Endocrinology — MCQs

Endocrinology — MCQs

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