Endocrinology Practice Questions

Q: Which of the following is NOT a cause of precocious puberty in girls?

Prader Willi syndrome. **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**.

Q: Which of the following is a rapid-acting insulin?

Glulisine. **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.

Q: Mental retardation is seen in all except?

Morquio syndrome. **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).

Q: Which of the following conditions is associated with precocious puberty?

McCune Albright syndrome. **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.

Q: A female child presents with virilization and hypertension with low plasma renin. What is the most likely diagnosis?

11β hydroxylase deficiency. ### 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**.

Q: 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?

Hexosaminidase A. **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.

Q: Hypoglycemia in neonates occurs when blood glucose is less than what value?

40 mg%. **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.

Question 1

Which of the following is NOT a cause of precocious puberty in girls?

Accepted Answer

Prader Willi syndrome

Answer

Hypothalamic hamartoma

Answer

Hypothyroidism

Answer

McCune Albright syndrome

Question 2

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?

Accepted Answer

Simple virilizing congenital adrenal hyperplasia

Answer

Classic salt-wasting 21-hydroxylase deficiency

Answer

Complete androgen insensitivity syndrome

Answer

5-alpha reductase deficiency

Question 3

Which of the following is a rapid-acting insulin?

Accepted Answer

Glulisine

Answer

Glargine

Answer

Detemir

Answer

Lente

Question 4

Mental retardation is seen in all except?

Accepted Answer

Morquio syndrome

Answer

Hurler syndrome

Answer

Sanfilippo syndrome

Answer

Hunter syndrome

Question 5

What is the most common cause of ambiguous genitalia in a newborn?

Accepted Answer

21 hydroxylase deficiency

Answer

11b-hydroxylase deficiency

Answer

17a-hydroxylase deficiency

Answer

3b-hydroxysteroid dehydrogenase deficiency

Question 6

Which of the following conditions is associated with precocious puberty?

Accepted Answer

McCune Albright syndrome

Answer

Hyperthyroidism

Answer

Addison's disease

Answer

Neuroblastoma

Question 7

A female child presents with virilization and hypertension with low plasma renin. What is the most likely diagnosis?

Accepted Answer

11β hydroxylase deficiency

Answer

21 α hydroxylase deficiency

Answer

3β hydroxylase deficiency

Answer

Conn's syndrome

Question 8

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?

Accepted Answer

Hexosaminidase A

Answer

Sphingomyelinase

Answer

Alpha galactosidase A

Answer

Beta galactosidase A

Question 9

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?

Accepted Answer

Growth hormone deficiency

Answer

Malabsorption

Answer

Adrenal tumor

Answer

Thyroxine deficiency

Question 10

Hypoglycemia in neonates occurs when blood glucose is less than what value?

Accepted Answer

40 mg%

Answer

20 mg%

Answer

60 mg%

Answer

10 mg%

Endocrinology — MCQs

Endocrinology — MCQs

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