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 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 4-year-old child presents with lethargy, delayed development of epiphysis, retarded dental eruption, growth retardation, mental retardation, and a slow relaxation component of deep tendon reflexes. What is the most likely diagnosis?

Hypothyroidism. **Explanation:** The clinical presentation described is a classic manifestation of **Juvenile Hypothyroidism**. Thyroid hormones are essential for the normal maturation of the skeletal, dental, and central nervous systems. * **Why Hypothyroidism is correct:** 1. **Skeletal & Dental:** Thyroid hormone is crucial for linear growth and bone maturation. Deficiency leads to growth retardation, **delayed epiphyseal appearance/dysgenesis**, and delayed dental eruption. 2. **Neurological:** It is vital for brain development; deficiency causes lethargy and **mental retardation** (permanent if not treated early). 3. **Reflexes:** A hallmark sign of hypothyroidism is the **"hung-up" reflex**, characterized by a slow relaxation phase of deep tendon reflexes (Woltman sign) due to delayed calcium reuptake by the sarcoplasmic reticulum. * **Why other options are incorrect:** * **Rickets:** Presents with bony deformities (bow legs, rachitic rosary) and delayed walking, but it does not typically cause mental retardation or slow reflex relaxation. * **Scurvy:** Caused by Vitamin C deficiency; presents with irritability, subperiosteal hemorrhages (pseudoparalysis), and "frog-leg" position, but not delayed epiphysis or mental retardation. * **Hypoparathyroidism:** Characterized by neuromuscular irritability (tetany, Chvostek/Trousseau signs) due to hypocalcemia, rather than slow reflexes. **NEET-PG High-Yield Pearls:** * **Most common cause of preventable mental retardation:** Congenital Hypothyroidism. * **Most common cause of Hypothyroidism (Worldwide):** Iodine deficiency. * **Most common cause (Developed countries/Sporadic):** Thyroid dysgenesis (Ectopic gland is the most common type). * **Radiological sign:** "Fragmentation" or "Stippled" epiphysis (Epiphyseal dysgenesis).

Q: Hypoglycemia, jaundice, and microphallus with an absent septum pellucidum are characteristic features of which syndrome?

De Morsier syndrome. **Explanation:** The correct answer is **De Morsier syndrome**, also known as **Septo-optic Dysplasia (SOD)**. This is a rare congenital disorder characterized by a classic triad: 1. **Optic nerve hypoplasia:** Leading to visual impairment. 2. **Midline brain defects:** Specifically an **absent septum pellucidum** or corpus callosum agenesis. 3. **Pituitary hypoplasia:** Resulting in combined pituitary hormone deficiencies. The clinical features mentioned—**hypoglycemia** (due to GH and ACTH deficiency), **jaundice** (cholestasis from GH/TSH deficiency), and **microphallus** (due to gonadotropin deficiency)—are all manifestations of congenital hypopituitarism associated with this syndrome. **Analysis of Incorrect Options:** * **Silver-Russell Syndrome:** Characterized by intrauterine growth restriction (IUGR), triangular facies, limb asymmetry, and clinodactyly. It does not involve midline brain defects. * **Kallmann Syndrome:** Defined by hypogonadotropic hypogonadism and **anosmia** (loss of smell) due to failure of GnRH neuron migration. It does not typically present with neonatal hypoglycemia or absent septum pellucidum. * **Kearns-Sayre Syndrome:** A mitochondrial DNA deletion syndrome characterized by the triad of progressive external ophthalmoplegia, pigmentary retinopathy, and heart block. **High-Yield Pearls for NEET-PG:** * **Imaging Gold Standard:** MRI is the investigation of choice to visualize the absent septum pellucidum and pituitary stalk abnormalities. * **Neonatal Emergency:** Any male neonate presenting with **microphallus and hypoglycemia** should be urgently evaluated for congenital hypopituitarism to prevent adrenal crisis. * **Association:** SOD is sometimes associated with mutations in the *HESX1* gene.

Q: An adolescent boy presents with endocrinopathy, fibrous dysplasia of bone, and hyperpigmentation. What is the probable diagnosis?

McCune Albright syndrome. ### Explanation The correct diagnosis is **McCune-Albright Syndrome (MAS)**. This condition is characterized by a classic triad resulting from a post-zygotic somatic mutation in the **GNAS1 gene**, which leads to constitutive activation of the Gs-alpha protein and overproduction of cAMP. **1. Why McCune-Albright Syndrome is Correct:** The clinical presentation in the question perfectly matches the MAS triad: * **Endocrinopathy:** Most commonly **precocious puberty** (gonadotropin-independent), but can also include hyperthyroidism, GH excess, or Cushing syndrome. * **Polyostotic Fibrous Dysplasia:** Bone is replaced by fibrous tissue, leading to fractures and a "ground-glass" appearance on X-ray. * **Hyperpigmentation:** Characterized by **Café-au-lait spots** with irregular borders, often described as the **"Coast of Maine"** appearance (unlike the smooth "Coast of California" spots seen in Neurofibromatosis Type 1). **2. Why the Other Options are Incorrect:** * **Alagille Syndrome:** An autosomal dominant disorder involving biliary hypoplasia (paucity of bile ducts), butterfly vertebrae, and peripheral pulmonary artery stenosis. It does not involve fibrous dysplasia. * **MEN Type 1 (Wermer Syndrome):** Characterized by the "3 Ps": **P**arathyroid hyperplasia, **P**ancreatic tumors, and **P**ituitary adenomas. * **MEN Type 2 (Sipple/Gorlin Syndrome):** Involves Medullary Thyroid Carcinoma, Pheochromocytoma, and either Parathyroid hyperplasia (2A) or Mucosal neuromas/Marfanoid habitus (2B). **High-Yield Clinical Pearls for NEET-PG:** * **Mutation:** Somatic mutation (not inherited); the severity depends on when the mutation occurs during embryogenesis (mosaicism). * **Radiology:** Fibrous dysplasia shows a characteristic **"Shepherd’s Crook" deformity** of the femur. * **Precocious Puberty:** In girls, it often presents with recurrent follicular cysts and vaginal bleeding.

Q: What is the recommended oral glucose dose for performing an oral glucose tolerance test in children?

1.75 gm/kg. **Explanation:** The **Oral Glucose Tolerance Test (OGTT)** is a standardized diagnostic tool used to assess glucose metabolism and diagnose Diabetes Mellitus or Impaired Glucose Tolerance. In pediatric practice, the glucose load must be weight-adjusted to ensure accuracy and safety, unlike the fixed 75g dose used for adults. **Why 1.75 gm/kg is correct:** The standard recommendation by the **World Health Organization (WHO)** and the **American Diabetes Association (ADA)** for children is **1.75 gm/kg of anhydrous glucose**. This dose provides a sufficient metabolic challenge to the pediatric endocrine system without causing excessive osmotic side effects. However, a crucial caveat is that the total dose should **not exceed 75 grams**, regardless of the child's weight. **Analysis of Incorrect Options:** * **1.5 gm/kg:** This dose is insufficient to meet the standardized diagnostic criteria and may lead to false-negative results (under-diagnosis). * **2 gm/kg & 2.5 gm/kg:** These doses are excessively high for a standard OGTT. Higher glucose loads increase the risk of nausea, vomiting (which invalidates the test), and osmotic diarrhea in children. **High-Yield Clinical Pearls for NEET-PG:** * **Preparation:** The child should have an unrestricted carbohydrate diet for 3 days prior and must fast for 8–12 hours before the test. * **Diagnostic Cut-offs (2-hour plasma glucose):** * **Normal:** <140 mg/dL * **Impaired Glucose Tolerance (IGT):** 140–199 mg/dL * **Diabetes Mellitus:** ≥200 mg/dL * **Growth Hormone (GH) Suppression Test:** In children suspected of Gigantism/Acromegaly, the same OGTT dose (1.75 gm/kg) is used. Failure to suppress GH to <1 ng/mL is diagnostic.

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.

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 conditions is associated with precocious puberty?

Accepted Answer

McCune Albright syndrome

Answer

Hyperthyroidism

Answer

Addison's disease

Answer

Neuroblastoma

Question 4

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 5

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 6

A 4-year-old child presents with lethargy, delayed development of epiphysis, retarded dental eruption, growth retardation, mental retardation, and a slow relaxation component of deep tendon reflexes. What is the most likely diagnosis?

Accepted Answer

Hypothyroidism

Answer

Rickets

Answer

Scurvy

Answer

Hypoparathyroidism

Question 7

Hypoglycemia, jaundice, and microphallus with an absent septum pellucidum are characteristic features of which syndrome?

Accepted Answer

De Morsier syndrome

Answer

Silver-Russell syndrome

Answer

Kallmann syndrome

Answer

Kearns-Sayre syndrome

Question 8

An adolescent boy presents with endocrinopathy, fibrous dysplasia of bone, and hyperpigmentation. What is the probable diagnosis?

Accepted Answer

McCune Albright syndrome

Answer

Alagille syndrome

Answer

MEN Type 1

Answer

MEN Type 2

Question 9

What is the recommended oral glucose dose for performing an oral glucose tolerance test in children?

Accepted Answer

1.75 gm/kg

Answer

1.5 gm/kg

Answer

2 gm/kg

Answer

2.5 gm/kg

Question 10

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.

Endocrinology — MCQs

Endocrinology — MCQs

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