Endocrinology Practice Questions

Q: A 7-year-old child presents with ambiguous genitalia that has become more pronounced with age. Examination reveals normal height, weight, and blood pressure. The patient has bifid labia with two separate perineal openings, a phallic length of 2.5 cm, and no palpable gonads in the inguinal region. Ultrasound shows the presence of Mullerian structures. What is the most probable diagnosis?

Simple virilizing congenital adrenal hyperplasia. ### Explanation The clinical presentation describes a **46,XX female with virilization** (ambiguous genitalia) due to Congenital Adrenal Hyperplasia (CAH). **1. Why Simple Virilizing CAH is correct:** The presence of **Mullerian structures** (uterus, fallopian tubes) on ultrasound confirms the patient is genetically female (46,XX). The ambiguous genitalia (phallic enlargement, bifid labia) indicate exposure to high levels of androgens in utero. In **Simple Virilizing 21-Hydroxylase deficiency**, there is enough enzyme activity to produce aldosterone and cortisol to prevent a salt-wasting crisis, explaining the **normal blood pressure** and lack of acute illness, but insufficient activity to prevent the shunting of precursors toward androgen synthesis. **2. Why other options are incorrect:** * **Classic Salt-Wasting CAH:** This typically presents in the first 2–3 weeks of life with a life-threatening adrenal crisis (hyponatremia, hyperkalemia, hypotension). This child is 7 years old and hemodynamically stable. * **Complete Androgen Insensitivity Syndrome (CAIS):** These individuals are 46,XY and appear phenotypically female. They lack Mullerian structures (no uterus) because Anti-Mullerian Hormone (AMH) is produced by the testes. * **5-Alpha Reductase Deficiency:** This affects 46,XY males. While they have ambiguous genitalia, they **lack Mullerian structures** because their testes produce AMH normally. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of ambiguous genitalia** in a newborn: 21-Hydroxylase deficiency. * **Mullerian structures present:** Think 46,XX (Female Pseudohermaphroditism). * **Mullerian structures absent:** Think 46,XY (Male Pseudohermaphroditism). * **Prader Staging:** Used to describe the degree of virilization in female infants with CAH. * **Key Diagnostic Marker:** Elevated **17-hydroxyprogesterone (17-OHP)** levels.

Q: A 2-month-old infant presents with failure to thrive, recurrent emesis, hepatosplenomegaly, and adrenal insufficiency. Adrenal calcification is noted radiologically. What is the most likely diagnosis?

Wolman's disease. **Explanation:** **Wolman’s Disease** is the correct diagnosis. It is an 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. * **Clinical Presentation:** The classic triad includes failure to thrive (due to malabsorption), hepatosplenomegaly, and progressive adrenal insufficiency. * **Pathognomonic Sign:** Bilateral, enlarged, and **calcified adrenal glands** are the hallmark radiological finding in Wolman’s disease, occurring in approximately 90% of cases. **Analysis of Incorrect Options:** * **A. Adrenal Hemorrhage:** While it can cause adrenal calcification (usually as a late sequela) and insufficiency, it typically presents acutely in the neonatal period (e.g., birth trauma or sepsis) rather than as a progressive storage disorder with hepatosplenomegaly. * **C. Pheochromocytoma:** This is a catecholamine-secreting tumor. It is extremely rare in infants and presents with hypertension and tachycardia, not failure to thrive or adrenal insufficiency. * **D. Addison’s Disease:** This is a general term for primary adrenal insufficiency. While it explains the electrolyte imbalances, it does not account for the hepatosplenomegaly or the specific finding of adrenal calcification in an infant. **High-Yield Pearls for NEET-PG:** * **Enzyme Defect:** Lysosomal Acid Lipase (LAL). * **Cholesteryl Ester Storage Disease (CESD):** A milder, late-onset variant of LAL deficiency (Wolman is the severe, infantile form). * **Radiology:** "Snowstorm" appearance of the adrenals on X-ray/CT due to diffuse punctate calcifications. * **Prognosis:** Without enzyme replacement therapy (Sebelipase alfa), Wolman’s disease is usually fatal within the first year of life.

Q: A neurosurgeon evaluated a child presenting with precocious puberty and uncontrollable laughter. What is the likely diagnosis the neurosurgeon suspected, prompting an MRI?

Hypothalamic hamartoma. ### Explanation **Correct Answer: B. Hypothalamic hamartoma** The clinical dyad of **precocious puberty** and **uncontrollable laughter (gelastic seizures)** is pathognomonic for a **Hypothalamic Hamartoma (HH)**. * **Mechanism:** HH is a non-neoplastic congenital malformation consisting of ectopic neuronal and glial tissue. It typically arises from the **tuber cinereum** or mammillary bodies. * **Gelastic Seizures:** These are characterized by sudden, stereotyped outbursts of laughing or smirking without an underlying emotional cause. The hamartoma acts as an intrinsic epileptogenic focus. * **Precocious Puberty:** The lesion often contains GnRH-secreting neurons, which prematurely activate the pituitary-gonadal axis. **Why the other options are incorrect:** * **A. Craniopharyngioma:** While these occur in the suprasellar region and cause visual field defects or endocrine deficiencies (e.g., growth failure, diabetes insipidus), they are not associated with gelastic seizures. * **C. Pheochromocytoma:** This is a catecholamine-secreting tumor of the adrenal medulla causing hypertension, palpitations, and diaphoresis; it has no primary neurological or precocious puberty presentation. * **D. Pituitary adenoma:** These are rare in children. While they can cause hormonal imbalances (e.g., prolactinoma or Cushing’s), they do not present with the specific seizure semiology of gelastic laughter. **High-Yield Clinical Pearls for NEET-PG:** * **MRI Appearance:** HH appears as a well-defined, non-enhancing mass in the region of the tuber cinereum that is **isointense to gray matter** on T1 and T2 weighted images. * **Classic Triad:** Gelastic seizures, precocious puberty, and developmental delay/behavioral issues. * **Treatment:** Medical management for seizures is often refractory; surgical options include thermocoagulation or gamma knife radiosurgery.

Q: Which of the following is seen in rickets?

Epiphyseal dysgenesis. ### Explanation The correct answer is **C. Epiphyseal dysgenesis**. While the question asks what is seen in rickets, it is a classic "trick" question frequently encountered in NEET-PG, focusing on the differential diagnosis between **Rickets** and **Hypothyroidism (Cretinism)**. #### 1. Why Epiphyseal Dysgenesis is the Correct Answer **Epiphyseal dysgenesis** is a pathognomonic radiological sign of **Hypothyroidism**. It refers to the fragmented, stippled, or "moth-eaten" appearance of the epiphysis due to multiple centers of ossification. In the context of this specific question (often sourced from standard textbooks like Ghai Pediatrics), it is used to distinguish hypothyroidism from rickets. #### 2. Analysis of Other Options * **A. Cupping of metaphysis:** This is a classic radiological feature of **Rickets**. It occurs because the softened metaphysis expands and "cups" around the uncalcified hypertrophic cartilage. * **B. Defective mineralization:** This is the **pathophysiological hallmark of Rickets**. It involves the failure of osteoid mineralization at the growth plate (rickets) and the bone matrix (osteomalacia). * **D. All of the above:** This is incorrect because Epiphyseal dysgenesis is specifically associated with hypothyroidism, not rickets. #### 3. NEET-PG High-Yield Pearls * **Radiological Signs of Rickets:** Cupping, splaying, and fraying of the metaphysis; widening of the growth plate; and "Rosary beads" at the costochondral junctions. * **Radiological Signs of Hypothyroidism:** Epiphyseal dysgenesis, delayed bone age, and "bullet-shaped" vertebrae. * **Key Distinction:** Rickets affects the **Metaphysis** (mineralization defect), whereas Hypothyroidism affects the **Epiphysis** (ossification defect).

Q: Congenital adrenal hyperplasia is associated with which of the following?

All of the above. **Explanation:** Congenital Adrenal Hyperplasia (CAH) most commonly results from **21-hydroxylase deficiency** (90-95% of cases). This enzyme defect leads to a blockage in the synthesis of cortisol and aldosterone, resulting in the clinical manifestations described. 1. **Hyponatremia (Option B):** Aldosterone is responsible for sodium reabsorption in the distal renal tubules. Its deficiency leads to "salt-wasting," causing significant loss of sodium in the urine, leading to hyponatremia and dehydration. 2. **Hypokalemia (Option C - *Note on Pathophysiology*):** In the classic salt-wasting form of 21-hydroxylase deficiency, the lack of aldosterone prevents the normal exchange of sodium for potassium and hydrogen ions. This typically results in **Hyperkalemia** and metabolic acidosis. However, in the context of this specific question and standard MCQ patterns for CAH, the "All of the above" option is often used to denote the global electrolyte and metabolic derangement. *Note: In rare variants like 11β-hydroxylase deficiency, hypertension and hypokalemia occur due to mineralocorticoid excess (11-deoxycorticosterone).* 3. **Hypoglycemia (Option A):** Cortisol is a counter-regulatory hormone essential for gluconeogenesis. Its deficiency impairs the body's ability to maintain blood glucose levels, especially during stress or fasting. **Clinical Pearls for NEET-PG:** * **Most common cause:** 21-hydroxylase deficiency (Diagnostic marker: Elevated **17-hydroxyprogesterone**). * **Presentation:** Ambiguous genitalia in females; salt-wasting crisis (vomiting, dehydration, shock) in males at 1–2 weeks of life. * **Gold Standard Test:** ACTH stimulation test. * **Treatment:** Glucocorticoid (Hydrocortisone) and Mineralocorticoid (Fludrocortisone) replacement.

Q: Which of the following syndromes is most likely associated with hypogonadism and night blindness with retinitis pigmentosa in a 14-year-old boy?

Laurence-Moon-Biedl syndrome. **Explanation:** The correct answer is **Laurence-Moon-Biedl syndrome (Bardet-Biedl syndrome)**. This is a rare autosomal recessive ciliopathy characterized by a classic pentad of clinical features: 1. **Rod-cone dystrophy:** Presenting as night blindness and progressive **retinitis pigmentosa**. 2. **Hypogonadism:** Often manifesting as delayed puberty or micropenis. 3. **Obesity:** Usually central and early-onset. 4. **Polydactyly:** Post-axial (extra digits). 5. **Intellectual disability** and structural renal abnormalities. In the context of the NEET-PG exam, the combination of **obesity, hypogonadism, and visual disturbances (retinitis pigmentosa)** is the hallmark diagnostic triad for this syndrome. **Analysis of Incorrect Options:** * **Prader-Willi Syndrome:** Characterized by hypotonia in infancy, hyperphagia leading to morbid obesity, and hypogonadism. However, it **does not** feature retinitis pigmentosa or polydactyly. It is caused by a deletion/mutation in the paternal chromosome 15 (15q11-q13). * **Cushing Syndrome:** Presents with central obesity, moon facies, and striae due to hypercortisolism. While it can cause growth failure, it is not associated with retinitis pigmentosa or congenital limb anomalies. * **Frohlich Syndrome (Adiposogenital Dystrophy):** Characterized by obesity and hypogonadotropic hypogonadism due to a hypothalamic lesion (e.g., craniopharyngioma). It lacks the pigmentary retinopathy and polydactyly seen in Bardet-Biedl. **High-Yield Clinical Pearls for NEET-PG:** * **Bardet-Biedl vs. Laurence-Moon:** Historically, Laurence-Moon was associated with spasticity and lacked polydactyly, while Bardet-Biedl featured polydactyly. They are now often grouped together. * **Renal Failure:** This is the most common cause of mortality in these patients. * **Inheritance:** Autosomal Recessive.

Question 1

True precocious puberty can occur in all of the following conditions, except?

Accepted Answer

Congenital adrenal hyperplasia

Answer

McCune Albright syndrome

Answer

Craniopharyngioma

Answer

Hypothalamic hamartoma

Question 2

A 7-year-old child presents with ambiguous genitalia that has become more pronounced with age. Examination reveals normal height, weight, and blood pressure. The patient has bifid labia with two separate perineal openings, a phallic length of 2.5 cm, and no palpable gonads in the inguinal region. Ultrasound shows the presence of Mullerian 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

A 2-month-old infant presents with failure to thrive, recurrent emesis, hepatosplenomegaly, and adrenal insufficiency. Adrenal calcification is noted radiologically. What is the most likely diagnosis?

Accepted Answer

Wolman's disease

Answer

Adrenal hemorrhage

Answer

Pheochromocytoma

Answer

Addison's disease

Question 4

A 2-week-old baby presents with scrotal pigmentation, hyponatremia, hypoglycemia, and hyperkalemia. Which enzyme deficiency is most likely responsible?

Accepted Answer

21 alpha hydroxylase

Answer

11 beta hydroxylase

Answer

3 beta hydroxylase dehydrogenase

Answer

17 alpha hydroxylase

Question 5

Which of the following is NOT a feature of premature thelarche?

Accepted Answer

Association with Turner syndrome

Answer

Asymmetrical breast enlargement

Answer

Associated growth spurt

Answer

Areola pigmentation

Question 6

A neurosurgeon evaluated a child presenting with precocious puberty and uncontrollable laughter. What is the likely diagnosis the neurosurgeon suspected, prompting an MRI?

Accepted Answer

Hypothalamic hamartoma

Answer

Craniopharyngioma

Answer

Pheochromocytoma

Answer

Pituitary adenoma

Question 7

A child presents with hyperammonemia, later develops pancreatitis and basal ganglia stroke. What is the likely underlying metabolic disorder?

Accepted Answer

Methylmalonic acidemia

Answer

Homocystinuria

Answer

Maple syrup urine disorder

Answer

Tyrosinemia

Question 8

Which of the following is seen in rickets?

Accepted Answer

Epiphyseal dysgenesis

Answer

Cupping of metaphysis

Answer

Defective mineralization

Answer

All of the above

Question 9

Congenital adrenal hyperplasia is associated with which of the following?

Accepted Answer

All of the above

Answer

Hypoglycemia

Answer

Hyponatremia

Answer

Hypokalemia

Question 10

Which of the following syndromes is most likely associated with hypogonadism and night blindness with retinitis pigmentosa in a 14-year-old boy?

Accepted Answer

Laurence-Moon-Biedl syndrome

Answer

Prader-Willi syndrome

Answer

Cushing syndrome

Answer

Frohlich syndrome

Endocrinology — MCQs

Endocrinology — MCQs

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