Endocrinology Practice Questions

Q: A newborn baby presents with tachycardia, hypotension, and irritability. USG revealed normal ovaries, and the karyotype is 46,XX. Which of the following biochemical abnormalities is not typically seen in this clinical scenario?

Hyperglycemia. **Explanation:** The clinical presentation of a newborn with tachycardia, hypotension (signs of shock), and irritability, combined with a **46,XX karyotype** and normal ovaries, is classic for **Congenital Adrenal Hyperplasia (CAH)**, most commonly due to **21-hydroxylase deficiency**. **1. Why Hyperglycemia is the Correct Answer:** In 21-hydroxylase deficiency, there is a block in the conversion of progesterone to deoxycorticosterone and 17-hydroxyprogesterone to 11-deoxycortisol. This leads to a **deficiency in Cortisol**. Since cortisol is a counter-regulatory hormone that promotes gluconeogenesis and glycogenolysis, its absence leads to **Hypoglycemia**, not hyperglycemia. Therefore, hyperglycemia is not typically seen in this scenario. **2. Analysis of Incorrect Options:** * **Hyponatremia & Hyperkalemia:** These occur due to **Aldosterone deficiency**. Aldosterone normally reabsorbs sodium and excretes potassium/hydrogen ions in the distal tubule. Its absence leads to "salt-wasting," resulting in low sodium and high potassium. * **Hypoglycemia:** As explained above, this is a direct result of glucocorticoid (cortisol) deficiency. **Clinical Pearls for NEET-PG:** * **Most Common Cause:** 21-hydroxylase deficiency (90-95% of CAH cases). * **Diagnostic Marker:** Elevated levels of **17-hydroxyprogesterone (17-OHP)**. * **Genitalia:** In 46,XX females, excess androgens cause **ambiguous genitalia** (virilization), though internal organs (ovaries/uterus) remain normal. * **Management:** Acute adrenal crisis requires aggressive fluid resuscitation (Normal Saline) and IV Hydrocortisone. * **Karyotype Tip:** Always look for the mismatch between karyotype (46,XX) and physical signs of virilization to spot CAH questions.

Q: Inheritance pattern of Familial hypophosphatemic Rickets is:

X-linked dominant. **Explanation:** **Familial Hypophosphatemic Rickets (FHR)**, also known as Vitamin D-resistant rickets, is most commonly caused by a mutation in the **PHEX gene** (Phosphate regulating gene with Homologies to endopeptidases on the X chromosome). 1. **Why X-linked Dominant is Correct:** The PHEX mutation leads to increased levels of **FGF-23** (Fibroblast Growth Factor-23), a phosphaturic hormone. Excess FGF-23 inhibits renal phosphate reabsorption and suppresses the activation of Vitamin D (1-alpha-hydroxylase activity). Because it is **X-linked dominant**, the condition is expressed in both hemizygous males and heterozygous females. It is one of the classic examples of X-linked dominant inheritance frequently tested in NEET-PG. 2. **Why Other Options are Incorrect:** * **Autosomal Recessive/Dominant:** While rare forms of hypophosphatemic rickets exist (e.g., ADHR or ARHR), the "Familial" or "Classic" form specifically refers to the X-linked variety. * **X-linked Recessive:** In FHR, a single mutant allele on the X chromosome is sufficient to cause the clinical phenotype in females; therefore, it is not recessive. **High-Yield Clinical Pearls for NEET-PG:** * **Biochemical Profile:** Low serum phosphate, **Normal** serum calcium, **Normal** 25(OH)D, but inappropriately low/normal 1,25(OH)₂D, and **Elevated Alkaline Phosphatase**. * **Clinical Feature:** Unlike nutritional rickets, **rachitic rosary and tetany are rare**; the primary manifestation is lower limb bowing and short stature. * **Treatment:** Oral phosphate supplementation and **Calcitriol** (active Vitamin D). * **Rule of Thumb:** If a question mentions "Rickets non-responsive to Vitamin D," think of FHR or Vitamin D Dependent Rickets (VDDR).

Q: The parents of a 4-week-old girl complain that their baby is apathetic and sluggish. On physical examination, the child's abdomen is large and exhibits an umbilical hernia. The skin is pale and cold, and the temperature is 35°C (95°F). Which of the following provides a plausible explanation for the signs and symptoms of this child?

Thyroid agenesis. **Explanation:** The clinical presentation of apathy, sluggishness, an umbilical hernia, a protuberant abdomen, and hypothermia (35°C) in a 4-week-old infant is a classic description of **Congenital Hypothyroidism**. **1. Why Thyroid Agenesis is Correct:** Thyroid dysgenesis (which includes **agenesis**, hypoplasia, or ectopy) is the most common cause of permanent congenital hypothyroidism (85%). Thyroid hormones are essential for metabolic rate and thermogenesis; hence, deficiency leads to hypothermia and cold, pale skin. The "sluggishness" reflects CNS depression and decreased metabolic activity. Other classic signs include a large fontanelle, macroglossia, and a characteristic umbilical hernia due to hypotonia of the abdominal muscles. **2. Why Incorrect Options are Wrong:** * **Cystic Fibrosis:** Typically presents with meconium ileus in neonates or failure to thrive and recurrent pneumonia later. It does not cause umbilical hernia or significant hypothermia. * **Muscular Dystrophy:** Duchenne or Becker muscular dystrophy usually manifests in early childhood (3–5 years) with motor delays, not as a multisystem metabolic collapse in a 4-week-old. * **Parathyroid Hyperplasia:** This would lead to hypercalcemia. While it can cause lethargy, it does not explain the umbilical hernia or the specific cutaneous and thermoregulatory findings seen here. **Clinical Pearls for NEET-PG:** * **Most common cause worldwide:** Iodine deficiency. * **Most common cause in non-endemic areas:** Thyroid dysgenesis (Agenesis is the most severe form). * **Screening:** Done via heel-prick test (TSH levels) at 48–72 hours of life. * **Treatment:** Levothyroxine must be started immediately to prevent permanent **neurocognitive impairment (Cretinism)**. * **Early Sign:** Prolonged physiological jaundice is often the earliest clinical clue.

Q: Which statin is indicated for an 8-year-old child diagnosed with heterozygous familial hypercholesterolemia?

Pravastatin. **Explanation:** The management of **Heterozygous Familial Hypercholesterolemia (HeFH)** in children focuses on lifestyle modifications followed by pharmacotherapy if LDL-C levels remain significantly elevated (typically >190 mg/dL or >160 mg/dL with a family history of early CVD). **Why Pravastatin is correct:** Pravastatin is unique because it is the only statin FDA-approved for use in children as young as **8 years old**. Most other statins are approved for children aged **10 years and older**. This makes Pravastatin the drug of choice when pharmacological intervention is required in the 8–10 year age bracket. **Analysis of Incorrect Options:** * **Simvastatin (A), Atorvastatin (C), and Lovastatin (D):** While these are commonly used to treat pediatric dyslipidemia, they are generally indicated for children **≥10 years of age**. Starting these medications in an 8-year-old would be considered "off-label" compared to the specific approval profile of Pravastatin. **High-Yield Clinical Pearls for NEET-PG:** * **Age of Initiation:** Statin therapy is generally not started before the age of 8 unless the child has **Homozygous** Familial Hypercholesterolemia (which requires much earlier, aggressive intervention). * **Monitoring:** Before starting statins, baseline Liver Function Tests (ALT/AST) and Creatine Kinase (CK) levels should be obtained. * **Teratogenicity:** Statins are **Category X**; adolescent females must be counseled on contraception. * **First-line:** Lifestyle and dietary changes (Step II AHA diet) should be trialed for 6–12 months before initiating drugs.

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

Secondary hypothyroidism. **Explanation:** Precocious puberty is defined as the onset of secondary sexual characteristics before age 8 in girls and age 9 in boys. Understanding the hormonal axis is key to identifying its causes. **Why Secondary Hypothyroidism is the correct answer:** Secondary (central) hypothyroidism is characterized by a deficiency in TSH or TRH. This leads to low thyroid hormone levels without an increase in pituitary activity that could cross-react with gonadotropin receptors. It is associated with **delayed puberty**, not precocious puberty. **Analysis of Incorrect Options:** * **Primary Hypothyroidism:** This is a classic cause of "Van Wyk-Grumbach Syndrome." In severe primary hypothyroidism, extremely high levels of TSH (due to lack of feedback) can cross-react with FSH receptors because they share a common alpha-subunit. This leads to precocious puberty, often characterized by multicystic ovaries and vaginal bleeding in girls, or testicular enlargement in boys, without a bone age advancement. * **Congenital Adrenal Hyperplasia (CAH):** This causes **peripheral precocious puberty** (isosexual in boys, contrasexual in girls). Excess adrenal androgens lead to early development of pubic hair and phallic enlargement. * **Theca Cell Tumor:** These are ovarian tumors that secrete estrogen directly, leading to peripheral precocious puberty (isosexual) in girls, characterized by breast development and vaginal bleeding. **NEET-PG High-Yield Pearls:** * **Van Wyk-Grumbach Syndrome:** The triad of primary hypothyroidism, precocious puberty, and delayed bone age (unique, as most precocity advances bone age). * **True vs. Pseudo:** Central precocity (GnRH dependent) always involves early activation of the HPO axis; Peripheral precocity (GnRH independent) involves exogenous or ectopic sex steroids. * **McCune-Albright Syndrome:** Triad of polyostotic fibrous dysplasia, café-au-lait spots (Coast of Maine), and peripheral precocious puberty.

Q: Precocious puberty is seen in which of the following conditions?

All of the above. **Explanation:** Precocious puberty is defined as the onset of secondary sexual characteristics before age 8 in girls and age 9 in boys. It is broadly classified into **Central (GnRH-dependent)** and **Peripheral (GnRH-independent)** types. * **McCune-Albright Syndrome (MAS):** This is a classic cause of **Peripheral Precocious Puberty**. It is characterized by the triad of polyostotic fibrous dysplasia, café-au-lait spots (Coast of Maine borders), and autonomous endocrine overactivity (most commonly precocious puberty due to ovarian cysts in girls). It results from a somatic mutation in the *GNAS* gene. * **CNS Irradiation:** Low-dose cranial irradiation (often for leukemia or brain tumors) can trigger **Central Precocious Puberty**. It is thought to disrupt the inhibitory pathways that normally keep the GnRH pulse generator dormant during childhood, leading to premature activation of the Hypothalamic-Pituitary-Gonadal (HPG) axis. * **Hypothyroidism:** Severe, untreated primary hypothyroidism can cause **Van Wyk-Grumbach Syndrome**. High levels of TSH cross-react with FSH receptors (due to molecular mimicry), leading to precocious puberty, multicystic ovaries, and delayed bone age (unlike other forms of precocity where bone age is advanced). **Clinical Pearls for NEET-PG:** 1. **Bone Age:** In most precocious puberty, bone age is **advanced**. In Hypothyroidism-induced precocity, bone age is **delayed**. 2. **Treatment:** GnRH agonists (e.g., Leuprolide) are the treatment of choice for Central Precocious Puberty. 3. **Hamartoma:** Hypothalamic hamartoma is the most common organic cause of Central Precocious Puberty.

Question 1

A newborn baby presents with tachycardia, hypotension, and irritability. USG revealed normal ovaries, and the karyotype is 46,XX. Which of the following biochemical abnormalities is not typically seen in this clinical scenario?

Accepted Answer

Hyperglycemia

Answer

Hypoglycemia

Answer

Hyponatremia

Answer

Hyperkalemia

Question 2

Inheritance pattern of Familial hypophosphatemic Rickets is:

Accepted Answer

X-linked dominant

Answer

Autosomal recessive

Answer

X-linked recessive

Answer

Autosomal dominant

Question 3

Ambiguous genitalia in males is due to which of the following conditions?

Accepted Answer

5-alpha reductase deficiency

Answer

Congenital adrenal hyperplasia

Answer

Cushing's disease

Answer

Aromatase deficiency

Question 4

The parents of a 4-week-old girl complain that their baby is apathetic and sluggish. On physical examination, the child's abdomen is large and exhibits an umbilical hernia. The skin is pale and cold, and the temperature is 35°C (95°F). Which of the following provides a plausible explanation for the signs and symptoms of this child?

Accepted Answer

Thyroid agenesis

Answer

Cystic fibrosis

Answer

Muscular dystrophy

Answer

Parathyroid hyperplasia

Question 5

Which statin is indicated for an 8-year-old child diagnosed with heterozygous familial hypercholesterolemia?

Accepted Answer

Pravastatin

Answer

Simvastatin

Answer

Atorvastatin

Answer

Lovastatin

Question 6

A child underwent bilateral adrenalectomy. Later, the child developed headache, visual field defect, and hyperpigmentation of the skin. What is the most probable diagnosis?

Accepted Answer

Nelson syndrome

Answer

Pituitary adenoma

Answer

Allgrove syndrome

Answer

Wolman syndrome

Question 7

What is the most common presentation of hypoparathyroidism beyond the neonatal period?

Accepted Answer

Tingling of extremities

Answer

Syncope secondary to prolonged QT intervals

Answer

Seizure

Answer

Bronchospasm

Question 8

Which of the following is NOT a known cause of precocious puberty?

Accepted Answer

Secondary hypothyroidism

Answer

Primary hypothyroidism

Answer

Congenital adrenal hyperplasia

Answer

Theca cell tumor of the ovary

Question 9

Precocious puberty is seen in which of the following conditions?

Accepted Answer

All of the above

Answer

Hypothyroidism

Answer

CNS irradiation

Answer

McCune-Albright syndrome

Question 10

Male pseudohermaphroditism is seen in which of the following conditions?

Accepted Answer

5-alpha-reductase deficiency

Answer

21-hydroxylase deficiency

Answer

17-hydroxylase deficiency

Answer

Gonadal dysgenesis

Endocrinology — MCQs

Endocrinology — MCQs

On this page

Practice by Chapter

Want unlimited practice?