Endocrinology Practice Questions

Q: Precocious puberty is treated by administering which of the following?

LHRH (Luteinizing Hormone-Releasing Hormone). **Explanation:** The treatment of choice for **Central Precocious Puberty (CPP)** is the administration of long-acting **GnRH (LHRH) agonists**. **Why LHRH is correct:** Under normal physiological conditions, GnRH is released from the hypothalamus in a **pulsatile** manner to stimulate the pituitary to release LH and FSH. However, when GnRH agonists (like Leuprolide or Goserelin) are administered **continuously**, they cause initial stimulation followed by a profound **down-regulation and desensitization** of the GnRH receptors on the pituitary gland. This leads to a suppression of gonadotropin (LH/FSH) secretion, effectively halting the production of sex steroids and pausing pubertal progression. **Why the other options are incorrect:** * **Testosterone (B) & Estrogen (C):** These are the very hormones responsible for the secondary sexual characteristics seen in precocious puberty. Administering them would worsen the condition and accelerate bone age maturation, leading to short adult stature. * **Gonadotrophins (D):** These (LH and FSH) directly stimulate the gonads to produce sex steroids. Administering them would further trigger pubertal development. **Clinical Pearls for NEET-PG:** * **Goal of Therapy:** The primary objectives are to stop secondary sexual development and, more importantly, to **prevent premature epiphyseal fusion** to preserve final adult height. * **Diagnosis:** CPP is confirmed by a "Pubertal" response to a GnRH stimulation test (elevated LH). * **Drug of Choice:** **Leuprolide acetate** (depot formulation) is most commonly used. * **Bone Age:** Always check bone age in these patients; it is typically advanced beyond the chronological age.

Q: A child presents with dry skin and mental retardation. What is the most likely diagnosis?

Hypothyroidism. **Explanation:** The clinical presentation of **dry skin (xeroderma)** and **mental retardation (intellectual disability)** is a classic hallmark of **Congenital Hypothyroidism**. Thyroid hormones are critical for the development of the central nervous system, especially during the first two years of life. A deficiency leads to irreversible brain damage if not treated early. Additionally, thyroid hormones regulate skin metabolism and sebum production; their absence leads to decreased glandular secretion, resulting in the characteristic dry, coarse, and thickened skin. **Analysis of Options:** * **Vitamin A deficiency:** While it causes dry skin (xerophthalmia and follicular hyperkeratosis), it does not typically cause mental retardation. It primarily affects vision (night blindness) and epithelial integrity. * **Cerebral palsy:** This is a permanent disorder of movement and posture due to non-progressive brain injury. While it involves motor and sometimes cognitive impairment, it is not associated with dry skin as a primary clinical feature. * **Hypothyroidism:** Correct. It explains both the metabolic skin changes and the neurodevelopmental delay (Cretinism). **NEET-PG High-Yield Pearls:** * **Most common cause:** Dysgenesis of the thyroid gland (Ectopy is the most common specific type). * **Early signs:** Prolonged physiological jaundice, large posterior fontanelle, umbilical hernia, and hoarse cry. * **Screening:** Best done between 48–72 hours of life (to avoid the physiological TSH surge). * **Treatment:** Levothyroxine is the drug of choice; the goal is to maintain T4 in the upper half of the normal range.

Q: What is the immediate treatment for a 10 kg infant presenting with tetany?

Intravenous calcium gluconate with cardiac monitoring. ### Explanation **Correct Answer: B. Intravenous calcium gluconate with cardiac monitoring** **Medical Concept:** Tetany in an infant is a clinical manifestation of **hypocalcemia**, characterized by increased neuromuscular irritability (carpopedal spasm, laryngospasm, or seizures). The immediate priority is to restore serum ionized calcium levels to prevent life-threatening complications like laryngeal stridor or cardiac arrhythmias. **Intravenous Calcium Gluconate (10%)** is the drug of choice. The standard dose is **1–2 ml/kg (100–200 mg/kg)**, administered slowly over 10–20 minutes. **Continuous cardiac monitoring** is mandatory because rapid infusion can cause bradycardia, heart block, or even cardiac arrest. **Why other options are incorrect:** * **A & C (Diazepam/Phenobarbital):** These are anti-epileptic drugs used for status epilepticus or febrile seizures. While tetany can present with seizures, the underlying cause is metabolic (low calcium). Treating with sedatives without correcting the calcium deficit will not resolve the tetany and may delay life-saving treatment. * **D (Wait and watch):** Tetany is a medical emergency. Delaying treatment can lead to airway obstruction (laryngospasm) or permanent neurological damage from hypocalcemic seizures. **NEET-PG High-Yield Pearls:** * **ECG Finding:** The classic sign of hypocalcemia is **prolonged QTc interval**. * **Administration Tip:** Always dilute calcium gluconate (usually 1:1 with 5% Dextrose or Normal Saline) and check for IV patency, as extravasation causes severe **tissue necrosis**. * **Refractory Hypocalcemia:** If calcium levels do not improve despite replacement, check **Magnesium levels**. Hypomagnesemia must be corrected first for calcium therapy to be effective. * **Chvostek’s and Trousseau’s signs** are clinical markers of latent tetany.

Q: What is the most common brain lesion causing central precocious puberty?

Hypothalamic hamartoma. **Explanation:** **Central Precocious Puberty (CPP)** is caused by the premature activation of the hypothalamic-pituitary-gonadal (HPG) axis, leading to early GnRH secretion. **Why Hypothalamic Hamartoma is the correct answer:** Hypothalamic hamartomas are the **most common organic (structural) brain lesions** causing CPP. These are non-neoplastic congenital malformations consisting of ectopic neural tissue. They act as "ectopic GnRH pulse generators," containing neurons that secrete GnRH in a pulsatile fashion, independent of normal inhibitory feedback. Clinically, they are often associated with **gelastic seizures** (characteristic laughing spells). **Analysis of Incorrect Options:** * **Tuberculous Meningitis (A):** While CNS infections or inflammation can trigger CPP due to scarring or irritation of the hypothalamus, they are significantly less common causes than hamartomas. * **Tuberous Sclerosis (B):** This neurocutaneous syndrome is associated with subependymal giant cell astrocytomas (SEGA) and cortical tubers, but it is not a primary or common cause of precocious puberty. * **Astrocytoma (C):** Optic gliomas and astrocytomas can cause CPP, especially in patients with Neurofibromatosis Type 1 (NF1), but statistically, hypothalamic hamartomas remain the most frequent lesion identified. **NEET-PG High-Yield Pearls:** * **Overall Most Common Cause:** In girls, CPP is most commonly **idiopathic** (80-90%). In boys, CPP is more likely to be **organic** (pathological lesion found in ~70%). * **Gold Standard Investigation:** Contrast-enhanced MRI of the brain is mandatory in all males with CPP and girls under 6–8 years to rule out lesions. * **Treatment of Choice:** Long-acting **GnRH agonists** (e.g., Leuprolide) to desensitize the pituitary and halt pubertal progression.

Q: A 13-year-old boy presented with episodes of headache, abdominal pain, palpitations, excessive sweating, and dizziness. He is also noted to have poor weight gain. On examination, he is hypertensive with tremors. What is the likely cause of the child's condition?

Pheochromocytoma. **Explanation:** The clinical presentation of paroxysmal headache, palpitations, excessive sweating (the classic triad), and hypertension strongly suggests **Pheochromocytoma**. This is a catecholamine-secreting tumor arising from chromaffin cells of the adrenal medulla (or extra-adrenal sympathetic chain). In children, the excess secretion of epinephrine and norepinephrine leads to a hypermetabolic state, explaining the poor weight gain and tremors, alongside episodic sympathetic overactivity. **Analysis of Options:** * **Pheochromocytoma (Correct):** The symptoms are a direct result of "catecholamine surges." Hypertension in children is often secondary; when combined with the classic triad and weight loss, pheochromocytoma is the most likely diagnosis. * **Diabetes Mellitus:** While it causes weight loss and polyuria, it does not typically present with paroxysmal hypertension or the classic sympathetic triad. * **Hysterical Fainting Spells:** These are diagnoses of exclusion. The presence of objective hypertension and tremors points toward an organic, endocrine cause rather than a psychogenic one. * **Hypothyroidism:** This typically presents with weight gain, bradycardia, lethargy, and cold intolerance—the exact opposite of this patient’s hyperdynamic state. **NEET-PG High-Yield Pearls:** * **Rule of 10s:** 10% are bilateral, 10% are malignant, 10% are extra-adrenal (Paragangliomas), and 10% are familial. Note: In children, the incidence of extra-adrenal and bilateral tumors is higher (approx. 25%). * **Diagnosis:** Best initial screening test is **24-hour urinary fractionated metanephrines** or plasma free metanephrines. * **Localization:** MIBG scan is used if CT/MRI fails to locate the tumor. * **Management:** Always give **Alpha-blockers (Phenoxybenzamine)** before Beta-blockers to avoid an unmatched alpha-constriction hypertensive crisis.

Question 1

Precocious puberty is treated by administering which of the following?

Accepted Answer

LHRH (Luteinizing Hormone-Releasing Hormone)

Answer

Testosterone

Answer

Estrogen

Answer

Gonadotrophin

Question 2

Hypokalemia in an infant may be due to all of the following except?

Accepted Answer

Diuretic therapy

Answer

Adrenal tumor

Answer

Thiazide therapy

Answer

Diarrhea

Question 3

A child presents with dry skin and mental retardation. What is the most likely diagnosis?

Accepted Answer

Hypothyroidism

Answer

Vitamin A deficiency

Answer

Cerebral palsy

Answer

All of the above

Question 4

A 5-month-old child presents with hepatomegaly, ketosis, hyperuricemia, and malaise. What is the most likely diagnosis?

Accepted Answer

Glycogen storage disease

Answer

Diabetes mellitus

Answer

Urea cycle defect

Answer

Mucopolysaccharidosis

Question 5

What is the commonest cause of primary amenorrhea with ambiguous genitalia in a female with 46XX chromosomes?

Accepted Answer

21-hydroxylase deficiency

Answer

17-hydroxylase deficiency

Answer

11-hydroxylase deficiency

Answer

Desmolase hydroxylase deficiency

Question 6

A 1-year-old child presents with thyroid swelling, abnormal weight gain, and poor activity. Laboratory tests reveal elevated TSH and very low T4. What is the most likely cause of this child's condition?

Accepted Answer

Dyshormonogenesis

Answer

Hypothalamic disease

Answer

Thyroid dysgenesis

Answer

End organ receptor insensitivity

Question 7

What is the immediate treatment for a 10 kg infant presenting with tetany?

Accepted Answer

Intravenous calcium gluconate with cardiac monitoring

Answer

Intravenous Diazepam

Answer

Intravenous slow phenobarbital

Answer

Wait and watch

Question 8

What is the most common brain lesion causing central precocious puberty?

Accepted Answer

Hypothalamic hamartoma

Answer

Tuberculous meningitis

Answer

Tuberous sclerosis

Answer

Astrocytoma

Question 9

Renal manifestations are seen in all of the following metabolic disorders EXCEPT?

Accepted Answer

Phenylketonuria

Answer

Tyrosinemia

Answer

Galactosemia

Answer

Hereditary fructose intolerance

Question 10

A 13-year-old boy presented with episodes of headache, abdominal pain, palpitations, excessive sweating, and dizziness. He is also noted to have poor weight gain. On examination, he is hypertensive with tremors. What is the likely cause of the child's condition?

Accepted Answer

Pheochromocytoma

Answer

Diabetes mellitus

Answer

Hysterical fainting spells

Answer

Hypothyroidism

Endocrinology — MCQs

Endocrinology — MCQs

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