Endocrinology — MCQs
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Which of the following is NOT a cause of precocious puberty in girls?
A 7-year-old child presents with ambiguous genitalia that have become more noticeable with age. Examination reveals normal height, weight, and blood pressure. The labia appear bifid with two separate perineal openings, and the phallic length is 2.5 cm. No gonads are palpable in the inguinal region. Ultrasound shows the presence of Müllerian structures. What is the most probable diagnosis?
Which of the following is a rapid-acting insulin?
Mental retardation is seen in all except?
What is the most common cause of ambiguous genitalia in a newborn?
Which of the following conditions is associated with precocious puberty?
A female child presents with virilization and hypertension with low plasma renin. What is the most likely diagnosis?
A 7-month-old child presented with neuro-developmental delay, loss of motor skills, increased startle reaction to noise, feeding difficulties, and failure to thrive. On examination, macrocephaly was noted along with myoclonus and spasticity. There was no evidence of corneal clouding or angiokeratomas. CT scan revealed no hepatosplenomegaly and no cardiac involvement. Fundoscopy revealed specific findings (details omitted for brevity in this example). Which enzyme deficiency is responsible for the above symptoms?
A 9-year-old boy presents with growth retardation and propensity to hypoglycemia. Physical examination reveals short stature, micropenis, increased fat, and a high-pitched voice. The skeletal survey reveals a bone age of 5 years. Which of the following is the most appropriate diagnosis?
Hypoglycemia in neonates occurs when blood glucose is less than what value?
Endocrinology Indian Medical PG Practice Questions and MCQs
Question 211: Which of the following is NOT a cause of precocious puberty in girls?
- A. Hypothalamic hamartoma
- B. Hypothyroidism
- C. McCune Albright syndrome
- D. Prader Willi syndrome (Correct Answer)
Explanation: **Explanation:** Precocious puberty is defined as the onset of secondary sexual characteristics before age 8 in girls. To answer this question, one must distinguish between conditions that accelerate puberty versus those that delay it. **Why Prader-Willi Syndrome (PWS) is the correct answer:** Prader-Willi Syndrome is a genetic disorder (deletion of paternal 15q11-q13) characterized by infantile hypotonia, hyperphagia leading to obesity, and **hypogonadotropic hypogonadism**. Because of the deficiency in GnRH secretion, patients typically experience **delayed puberty** or incomplete pubertal development, rather than precocious puberty. **Analysis of Incorrect Options:** * **Hypothalamic Hamartoma:** This is the most common brain tumor causing **GnRH-dependent (Central) Precocious Puberty**. It acts as an ectopic pacemaker, secreting GnRH pulses. * **Hypothyroidism:** Severe, untreated primary hypothyroidism can cause **Van Wyk-Grumbach Syndrome**. High levels of TSH cross-react with FSH receptors, leading to precocious puberty (often with multicystic ovaries and delayed bone age). * **McCune-Albright Syndrome:** A classic cause of **GnRH-independent (Peripheral) Precocious Puberty**. It is characterized by the triad of polyostotic fibrous dysplasia, café-au-lait spots (coast of Maine), and autonomous endocrine overactivity (precocious puberty). **High-Yield Clinical Pearls for NEET-PG:** * **Central Precocious Puberty (CPP):** Always isosexual; bone age is advanced; GnRH stimulation test shows a pubertal LH response. * **Peripheral Precocious Puberty:** Can be isosexual or contrasexual; GnRH stimulation test shows a flat/pre-pubertal LH response. * **Bone Age Paradox:** In most precocious puberty, bone age is **advanced**. In Hypothyroidism-induced precocity, bone age is **delayed**.
Question 212: A 7-year-old child presents with ambiguous genitalia that have become more noticeable with age. Examination reveals normal height, weight, and blood pressure. The labia appear bifid with two separate perineal openings, and the phallic length is 2.5 cm. No gonads are palpable in the inguinal region. Ultrasound shows the presence of Müllerian structures. What is the most probable diagnosis?
- A. Classic salt-wasting 21-hydroxylase deficiency
- B. Simple virilizing congenital adrenal hyperplasia (Correct Answer)
- C. Complete androgen insensitivity syndrome
- D. 5-alpha reductase deficiency
Explanation: ### Explanation The clinical presentation points toward **Congenital Adrenal Hyperplasia (CAH)**, specifically the **Simple Virilizing (SV)** form. **1. Why the Correct Answer is Right:** The presence of **Müllerian structures** (uterus/fallopian tubes) on ultrasound and the absence of palpable gonads confirm the child is a **46,XX female** with virilized external genitalia (ambiguous genitalia). In 21-hydroxylase deficiency, excess androgens cause virilization. The key differentiator here is the **normal blood pressure and absence of salt-wasting crises** (normal electrolytes/hydration) at age 7, which excludes the "Salt-Wasting" form. Simple Virilizing CAH presents with ambiguous genitalia at birth but lacks the life-threatening aldosterone deficiency, allowing the child to grow normally until progressive virilization or precocious puberty is noted. **2. Why Other Options are Wrong:** * **Classic Salt-Wasting 21-OH Deficiency:** This typically presents in the first 2–3 weeks of life with a life-threatening adrenal crisis (hyponatremia, hyperkalemia, and hypotension). A 7-year-old would not survive untreated. * **Complete Androgen Insensitivity Syndrome (CAIS):** These individuals are 46,XY and have a female phenotype. Crucially, they **lack Müllerian structures** (due to Anti-Müllerian Hormone production by testes) and have "blind-ending" vaginas. * **5-alpha Reductase Deficiency:** This affects 46,XY males. While they have ambiguous genitalia, they **do not have Müllerian structures** and would have palpable or intra-abdominal testes. **3. NEET-PG Clinical Pearls:** * **Most common cause of ambiguous genitalia** in a newborn is CAH (21-hydroxylase deficiency). * **Karyotype in CAH:** Always 46,XX for female pseudohermaphroditism. * **Biochemical Marker:** Elevated **17-hydroxyprogesterone (17-OHP)**. * **Müllerian structures presence** is the "gold standard" clinical clue to differentiate a virilized female (CAH) from an undervirilized male (AIS/5-alpha reductase deficiency).
Question 213: Which of the following is a rapid-acting insulin?
- A. Glargine
- B. Detemir
- C. Lente
- D. Glulisine (Correct Answer)
Explanation: **Explanation:** Insulin analogues are classified based on their onset and duration of action. **Glulisine** is a **rapid-acting insulin** analogue. It is designed to mimic the postprandial (after-meal) insulin spike. By modifying the amino acid sequence (replacing asparagine with lysine and lysine with glutamic acid), these analogues prevent the formation of hexamers, allowing for rapid absorption into the bloodstream. **Analysis of Options:** * **Glulisine (Correct):** Along with **Lispro** and **Aspart**, Glulisine has an onset of action within 5–15 minutes and a peak effect at 1 hour. It is ideal for bolus coverage during meals. * **Glargine & Detemir (Incorrect):** These are **long-acting (basal) insulin** analogues. They provide a steady, "peakless" level of insulin for approximately 24 hours to maintain glycemic control between meals and overnight. * **Lente (Incorrect):** This is an **intermediate-acting** insulin (human insulin zinc suspension). It has a slower onset and longer duration than regular insulin but has largely been replaced by NPH or long-acting analogues in modern pediatric practice. **High-Yield NEET-PG Pearls:** 1. **Mnemonic for Rapid-acting:** "No **L**ag" (**L**ispro, **A**spart, **G**lulisine). 2. **Route:** Rapid-acting analogues are the preferred choice for **Continuous Subcutaneous Insulin Infusion (CSII)** or insulin pumps. 3. **Site of Absorption:** Abdomen > Arm > Thigh > Buttock. 4. **Mixing:** Rapid-acting insulins can be mixed with NPH, but Glargine/Detemir should never be mixed in the same syringe as their acidic pH can cause precipitation.
Question 214: Mental retardation is seen in all except?
- A. Hurler syndrome
- B. Sanfilippo syndrome
- C. Hunter syndrome
- D. Morquio syndrome (Correct Answer)
Explanation: **Explanation:** The question tests the ability to differentiate between various **Mucopolysaccharidoses (MPS)** based on their clinical presentation, specifically the involvement of the central nervous system (CNS). **Why Morquio Syndrome is the correct answer:** Morquio Syndrome (MPS IV) is unique among the mucopolysaccharidoses because it is characterized by severe skeletal dysplasia (spondyloepiphyseal dysplasia) but **spares the intellect**. Patients typically have normal intelligence. The primary morbidity arises from systemic bone involvement, ligamentous laxity, and potential atlantoaxial instability leading to spinal cord compression, rather than cognitive decline. **Analysis of Incorrect Options:** * **Hurler Syndrome (MPS I-H):** This is the most severe form of MPS. It is characterized by early-onset developmental delay, progressive mental retardation, corneal clouding, and hepatosplenomegaly. * **Hunter Syndrome (MPS II):** This is the only **X-linked recessive** MPS. The severe form (Type A) involves progressive mental retardation and behavioral issues, though it lacks corneal clouding. * **Sanfilippo Syndrome (MPS III):** This syndrome is primarily a neurodegenerative disorder. It presents with the most severe and rapid central nervous system involvement among all MPS types, leading to profound mental retardation and hyperactivity. **NEET-PG High-Yield Pearls:** 1. **Intellect Spared:** MPS IV (Morquio) and MPS VI (Maroteaux-Lamy) typically present with **normal intelligence**. 2. **Corneal Clouding:** Present in all MPS except **Hunter (MPS II)** and **Sanfilippo (MPS III)**. 3. **Inheritance:** All MPS are Autosomal Recessive except **Hunter Syndrome**, which is **X-linked Recessive**. 4. **Enzyme Deficiency in Morquio:** Galactose-6-sulfatase (MPS IVA) or Beta-galactosidase (MPS IVB).
Question 215: What is the most common cause of ambiguous genitalia in a newborn?
- A. 21 hydroxylase deficiency (Correct Answer)
- B. 11b-hydroxylase deficiency
- C. 17a-hydroxylase deficiency
- D. 3b-hydroxysteroid dehydrogenase deficiency
Explanation: **Explanation:** Ambiguous genitalia in a newborn is most frequently caused by **Congenital Adrenal Hyperplasia (CAH)**, specifically due to **21-hydroxylase deficiency**, which accounts for approximately **90-95% of all CAH cases**. **Why 21-hydroxylase deficiency is correct:** In this condition, a block in the conversion of progesterone to deoxycorticosterone (and 17-OHP to 11-deoxycortisol) leads to a deficiency in cortisol and aldosterone. This lack of negative feedback causes an increase in ACTH, which overstimulates the adrenal cortex. The accumulated precursors are shunted into the androgen pathway, leading to **hyperandrogenism**. In genetic females (46,XX), this results in virilization of the external genitalia (clitoromegaly, labial fusion), making it the leading cause of female pseudohermaphroditism. **Analysis of Incorrect Options:** * **11β-hydroxylase deficiency:** This is the second most common cause (approx. 5%). While it also causes virilization, it is uniquely characterized by **hypertension** due to the accumulation of 11-deoxycorticosterone (a mineralocorticoid). * **17α-hydroxylase deficiency:** This leads to a decrease in both cortisol and sex hormones. It presents with delayed puberty and hypertension, but **not** ambiguous genitalia in females (it causes undervirilization in males). * **3β-hydroxysteroid dehydrogenase deficiency:** A rare form that affects all classes of adrenal and gonadal steroids. It causes incomplete virilization in males and mild virilization in females, but is far less common than 21-hydroxylase deficiency. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Elevated levels of **17-hydroxyprogesterone (17-OHP)**. * **Classic Presentation:** Salt-wasting crisis (hyponatremia, hyperkalemia, hypotension) usually occurs in the 2nd week of life. * **Management:** Glucocorticoid (Hydrocortisone) and Mineralocorticoid (Fludrocortisone) replacement. * **Karyotype:** Always perform a karyotype in newborns with bilateral impalpable gonads and ambiguous genitalia to rule out 46,XX CAH.
Question 216: Which of the following conditions is associated with precocious puberty?
- A. Hyperthyroidism
- B. Addison's disease
- C. McCune Albright syndrome (Correct Answer)
- D. Neuroblastoma
Explanation: **Explanation:** **McCune-Albright Syndrome (MAS)** is a classic cause of **Peripheral Precocious Puberty** (GnRH-independent). It is caused by a somatic mutation in the **GNAS1 gene**, leading to constitutive activation of the G-protein signaling pathway. This results in autonomous overproduction of hormones. In females, this typically presents as recurrent follicular cysts and vaginal bleeding. The classic clinical triad includes: 1. **Precocious puberty** 2. **Polyostotic fibrous dysplasia** (bone lesions) 3. **Café-au-lait spots** (typically large, unilateral with irregular "Coast of Maine" borders). **Analysis of Incorrect Options:** * **Hyperthyroidism:** While severe **Hypothyroidism** can cause pseudoprecocity (Van Wyk-Grumbach syndrome) due to TSH cross-reactivity with FSH receptors, hyperthyroidism is not a recognized cause of precocious puberty. * **Addison’s Disease:** This is primary adrenal insufficiency (deficiency of cortisol/aldosterone). It leads to delayed puberty rather than precocious puberty. * **Neuroblastoma:** This is a neural crest tumor that typically presents with an abdominal mass, opsoclonus-myoclonus, or hypertension. It does not secrete gonadotropins or sex steroids. **High-Yield Clinical Pearls for NEET-PG:** * **Central vs. Peripheral:** Central precocious puberty is GnRH-dependent (early activation of HPO axis); Peripheral is GnRH-independent (excess sex steroids from gonads/adrenals/exogenous sources). * **Bone Age:** Always advanced in true precocious puberty. * **Treatment for MAS:** Aromatase inhibitors (e.g., Letrozole) or Estrogen receptor antagonists (e.g., Tamoxifen) are used to manage the peripheral precocity. GnRH analogues are **not** effective initially.
Question 217: A female child presents with virilization and hypertension with low plasma renin. What is the most likely diagnosis?
- A. 21 α hydroxylase deficiency
- B. 11β hydroxylase deficiency (Correct Answer)
- C. 3β hydroxylase deficiency
- D. Conn's syndrome
Explanation: ### Explanation The clinical presentation of **virilization** combined with **hypertension** and **low renin** is the classic triad for **11β-hydroxylase deficiency**, the second most common cause of Congenital Adrenal Hyperplasia (CAH). **Why Option B is Correct:** In 11β-hydroxylase deficiency, the conversion of 11-deoxycortisol to cortisol and 11-deoxycorticosterone (DOC) to corticosterone is blocked. This leads to: 1. **Virilization:** Excess progesterone and 17-OHP are shunted into the androgen pathway, causing ambiguous genitalia in females. 2. **Hypertension:** The buildup of **11-deoxycorticosterone (DOC)** is key. DOC is a potent mineralocorticoid; its excess causes salt and water retention, leading to hypertension and feedback **suppression of Renin**. **Why Other Options are Incorrect:** * **A. 21α hydroxylase deficiency:** This is the most common CAH. While it causes virilization, it leads to a deficiency of mineralocorticoids (salt-wasting), resulting in **hypotension** and **high renin**. * **C. 3β hydroxylase deficiency:** This rare form causes a deficit in all adrenal steroids. It typically presents with salt-wasting (hypotension) and incomplete virilization/ambiguous genitalia in both sexes. * **D. Conn’s Syndrome:** This is primary hyperaldosteronism. While it causes hypertension and low renin, it **does not cause virilization** as it does not involve the androgen pathway. **High-Yield Clinical Pearls for NEET-PG:** * **11β-hydroxylase deficiency:** Think "Hyper-Androgenism + Hypertension." * **21α-hydroxylase deficiency:** Think "Hyper-Androgenism + Hypotension/Salt-wasting." * **17α-hydroxylase deficiency:** Think "Hypo-Androgenism (delayed puberty) + Hypertension." * **Mnemonic:** If the enzyme starts with **1** (11, 17), it causes **Hypertension**. If the enzyme ends with **1** (11, 21), it causes **Virilization**.
Question 218: A 7-month-old child presented with neuro-developmental delay, loss of motor skills, increased startle reaction to noise, feeding difficulties, and failure to thrive. On examination, macrocephaly was noted along with myoclonus and spasticity. There was no evidence of corneal clouding or angiokeratomas. CT scan revealed no hepatosplenomegaly and no cardiac involvement. Fundoscopy revealed specific findings (details omitted for brevity in this example). Which enzyme deficiency is responsible for the above symptoms?
- A. Hexosaminidase A (Correct Answer)
- B. Sphingomyelinase
- C. Alpha galactosidase A
- D. Beta galactosidase A
Explanation: **Explanation:** The clinical presentation describes a classic case of **Tay-Sachs Disease** (GM2 Gangliosidosis). The key diagnostic triad includes progressive neurodegeneration (loss of motor skills), an exaggerated **startle response** (hyperacusis), and a **cherry-red spot** on the macula (implied fundoscopy finding). The presence of **macrocephaly** (due to reactive gliosis) and the specific **absence of hepatosplenomegaly** are pathognomonic features that differentiate it from other lipid storage disorders. 1. **Hexosaminidase A (Correct):** Deficiency of this enzyme leads to the accumulation of GM2 ganglioside in the gray matter of the brain. This causes the characteristic neuro-regression, macrocephaly, and seizures seen in this infant. 2. **Sphingomyelinase (Incorrect):** Deficiency causes **Niemann-Pick Disease (Type A)**. While it presents with a cherry-red spot and neurodegeneration, it is characterized by **prominent hepatosplenomegaly**, which was absent in this patient. 3. **Alpha-galactosidase A (Incorrect):** Deficiency causes **Fabry Disease**. This presents later in life with angiokeratomas, peripheral neuropathy (burning pain), and renal/cardiac involvement, rather than early-onset neuro-regression. 4. **Beta-galactosidase A (Incorrect):** Deficiency causes **GM1 Gangliosidosis**. This presents with a cherry-red spot and neurodegeneration but typically includes **hepatosplenomegaly** and skeletal abnormalities (dysostosis multiplex). **NEET-PG High-Yield Pearls:** * **Tay-Sachs vs. Niemann-Pick:** Both have cherry-red spots, but Tay-Sachs has **No** organomegaly (No "Pick"ing of the liver/spleen). * **Pathology:** "Onion-skin" lysosomes are seen on electron microscopy in Tay-Sachs. * **Genetics:** Autosomal Recessive; common in Ashkenazi Jews. * **Macrocephaly:** In a child with neuro-regression, think Tay-Sachs, Alexander disease, or Canavan disease.
Question 219: A 9-year-old boy presents with growth retardation and propensity to hypoglycemia. Physical examination reveals short stature, micropenis, increased fat, and a high-pitched voice. The skeletal survey reveals a bone age of 5 years. Which of the following is the most appropriate diagnosis?
- A. Malabsorption
- B. Growth hormone deficiency (Correct Answer)
- C. Adrenal tumor
- D. Thyroxine deficiency
Explanation: **Explanation:** The clinical presentation described is a classic case of **Growth Hormone Deficiency (GHD)**, specifically Isolated Growth Hormone Deficiency (IGHD). **1. Why Growth Hormone Deficiency is correct:** * **Growth Retardation & Short Stature:** GH is essential for linear growth; its deficiency leads to proportionate short stature. * **Micropenis & Hypoglycemia:** In children, GH (along with ACTH) is crucial for maintaining blood glucose. Hypoglycemia in a child with a micropenis strongly suggests a deficiency in the hypothalamic-pituitary axis (GH and/or Gonadotropins). * **Physical Features:** "Cherubic" appearance (increased truncal fat with a youthful face) and a high-pitched voice (due to an underdeveloped larynx) are hallmark signs. * **Delayed Bone Age:** A significant lag in bone age (5 years vs. chronological age of 9) is characteristic of endocrine causes of short stature. **2. Why the other options are incorrect:** * **Malabsorption:** While it causes growth failure, it typically presents with low BMI (wasting), gastrointestinal symptoms, and would not explain micropenis or a high-pitched voice. * **Adrenal Tumor:** This would typically cause virilization (precocious puberty, enlarged penis) or Cushingoid features (hypertension, striae), rather than micropenis and GH-type growth delay. * **Thyroxine Deficiency (Hypothyroidism):** While it causes short stature and delayed bone age, it is usually associated with mental sluggishness, coarse skin, and constipation. It does not typically cause micropenis or hypoglycemia. **Clinical Pearls for NEET-PG:** * **Laron Syndrome:** A condition of GH insensitivity (receptor defect) where GH levels are actually *high*, but clinical features are identical to GHD. * **Diagnosis:** The gold standard is a **GH stimulation test** (using insulin, glucagon, or clonidine) showing GH levels <10 ng/mL. * **Bone Age:** In GHD, Bone Age < Height Age < Chronological Age.
Question 220: Hypoglycemia in neonates occurs when blood glucose is less than what value?
- A. 20 mg%
- B. 40 mg% (Correct Answer)
- C. 60 mg%
- D. 10 mg%
Explanation: **Explanation:** In neonatology, hypoglycemia is defined as a blood glucose level low enough to cause symptoms or potential neurological injury. According to the **World Health Organization (WHO)** and standard pediatric guidelines (such as Ghai Pediatrics), neonatal hypoglycemia is generally defined as a blood glucose level **<40 mg/dL** (or <45 mg/dL in some protocols) within the first 24–72 hours of life. The physiological basis for this threshold is the "nadir" that occurs 1–2 hours after birth, where glucose levels naturally drop before stabilizing. A value below 40 mg% indicates that the neonate’s metabolic demands are exceeding their glycogen stores or gluconeogenic capacity, necessitating intervention to prevent long-term neurodevelopmental sequelae. **Analysis of Options:** * **Option A (20 mg%):** This is dangerously low and represents "severe" hypoglycemia. While it was historically used as a cutoff for immediate IV intervention, it is not the diagnostic threshold. * **Option B (40 mg%):** **Correct.** This is the standard operational threshold for defining hypoglycemia in a newborn. * **Option C (60 mg%):** This is considered a normal/optimal range for an older infant or child, but it is too high to be the diagnostic cutoff for a neonate. * **Option D (10 mg%):** This represents critical, life-threatening hypoglycemia and is not a diagnostic standard. **Clinical Pearls for NEET-PG:** * **Symptomatic vs. Asymptomatic:** If blood glucose is <40 mg/dL and the baby is symptomatic (jitteriness, lethargy, seizures), immediate **IV 10% Dextrose (2 ml/kg bolus)** is required. * **High-Risk Groups:** Infants of diabetic mothers (IDM), Small for Gestational Age (SGA), and preterm babies are at the highest risk. * **Whipple’s Triad:** Remember this for general hypoglycemia: (1) Symptoms of hypoglycemia, (2) Low plasma glucose, (3) Relief of symptoms after glucose administration.
Practice by Chapter
Disorders of Growth
Practice Questions
Thyroid Disorders
Practice Questions
Disorders of Puberty
Practice Questions
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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