Endocrinology Practice Questions

Q: What is the treatment for a case of virilizing adrenal hyperplasia?

None of these. **Explanation:** The clinical scenario describes **Congenital Adrenal Hyperplasia (CAH)**, most commonly caused by **21-hydroxylase deficiency**. In this condition, a block in the cortisol synthesis pathway leads to a lack of negative feedback on the pituitary, resulting in **excessive ACTH secretion**. This overstimulates the adrenal cortex, shunting precursors toward the androgen pathway, causing virilization. **Why "None of these" is correct:** The primary goal of treatment is to replace the deficient hormone (Cortisol) and suppress the excess ACTH. The treatment of choice is **Glucocorticoids (e.g., Hydrocortisone)**. By providing exogenous cortisol, the feedback loop is restored, ACTH levels drop, and the stimulus for adrenal androgen production is removed. In salt-wasting forms, **Mineralocorticoids (Fludrocortisone)** are also required. **Analysis of Incorrect Options:** * **A. Estrogens:** These do not address the underlying enzyme deficiency or the ACTH excess. * **B. Antiandrogens:** While they may block peripheral action, they do not treat the life-threatening cortisol/aldosterone deficiency. * **C. ACTH:** Administering ACTH would worsen the condition by further stimulating the adrenal gland to produce more androgens. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** 21-hydroxylase deficiency (90% of cases). * **Diagnostic Marker:** Elevated **17-hydroxyprogesterone (17-OHP)** levels. * **Clinical Presentation:** Ambiguous genitalia in females; salt-wasting crisis (hyponatremia, hyperkalemia, hypotension) in the first 2 weeks of life. * **Karyotype:** In a virilized female (Prader staging), the karyotype remains **46, XX**.

Q: What is the inheritance pattern of congenital adrenal hyperplasia?

Autosomal Recessive (AR). **Explanation:** **Congenital Adrenal Hyperplasia (CAH)** is a group of inherited disorders characterized by a deficiency in one of the enzymes required for cortisol synthesis in the adrenal cortex. 1. **Why Autosomal Recessive (AR) is correct:** CAH follows an **Autosomal Recessive** inheritance pattern. This means an affected individual must inherit two mutated alleles (one from each parent). The parents are typically asymptomatic carriers. The most common cause (95% of cases) is a deficiency of the enzyme **21-hydroxylase**, encoded by the *CYP21A2* gene located on Chromosome 6. Because it is an enzymatic defect, it follows the general rule in genetics that most inborn errors of metabolism are inherited in an AR fashion. 2. **Why other options are incorrect:** * **Autosomal Dominant (AD):** AD disorders usually involve structural proteins or receptors (e.g., Marfan syndrome). CAH involves enzyme deficiencies, which rarely manifest in a heterozygous state. * **X-linked (XD/XR):** CAH affects males and females equally and involves genes located on autosomes (like Chromosome 6 or 11), ruling out sex-linked inheritance. **High-Yield Clinical Pearls for NEET-PG:** * **Most Common Enzyme Deficiency:** 21-hydroxylase deficiency (leads to increased 17-OH Progesterone). * **Classic Presentation:** Salt-wasting (hyponatremia, hyperkalemia, hypotension) and virilization (ambiguous genitalia in females). * **Diagnostic Marker:** Elevated serum **17-hydroxyprogesterone (17-OHP)**. * **Treatment:** Glucocorticoids (to suppress ACTH and replace cortisol) and Mineralocorticoids (Fludrocortisone for salt-wasters). * **Screening:** Newborn screening for CAH is now part of many national programs using the heel-prick test for 17-OHP.

Q: A 15-year-old girl presents with short stature, neck webbing, and sexual infantilism. She is also found to have coarctation of the aorta. A chromosomal analysis is likely to demonstrate which of the following?

XO karyotype. ### Explanation **Correct Answer: C. XO karyotype** The clinical triad of **short stature, neck webbing (pterygium colli), and sexual infantilism** (due to streak ovaries/gonadal dysgenesis) in a phenotypic female is the classic presentation of **Turner Syndrome**. The presence of **coarctation of the aorta** (the most common cardiovascular malformation in Turner syndrome, occurring in ~15-20% of cases) further confirms the diagnosis. Turner syndrome is most commonly caused by **45,X monosomy** (XO karyotype), resulting from the loss of part or all of an X chromosome. **Analysis of Incorrect Options:** * **A. Mutation at chromosome 15q21.1:** This is associated with **Marfan Syndrome** (FBN1 gene). While Marfan patients have cardiac issues (aortic root dilation), they typically present with tall stature and arachnodactyly, the opposite of this patient's phenotype. * **B. Trisomy 21:** This causes **Down Syndrome**. While associated with cardiac defects (most commonly Endocardial Cushion Defects/AVSD), it presents with distinct facies, intellectual disability, and hypotonia rather than sexual infantilism and neck webbing. * **D. Defect at chromosome 4p16:** This is the locus for **Wolf-Hirschhorn Syndrome**, characterized by "Greek warrior helmet" facies, microcephaly, and severe developmental delay. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of primary amenorrhea:** Turner Syndrome. * **Skeletal finding:** Positive **Archibald sign** (short 4th metacarpal) and Madelung deformity. * **Renal association:** **Horseshoe kidney** is the most common renal anomaly. * **Lymphedema:** Newborns often present with lymphedema of hands and feet and cystic hygroma. * **Genetics:** 50% are 45,X; others are mosaics (e.g., 45,X/46,XX) or structural abnormalities (isochromosome Xq). Mosaics have a higher risk of gonadoblastoma if a Y chromosome fragment is present.

Q: What is the most common cause of delayed puberty in males?

Constitutional delay. **Explanation:** **Constitutional Delay of Growth and Puberty (CDGP)** is the most common cause of delayed puberty in both males and females, accounting for approximately 60–80% of cases. It is essentially a "late bloomer" phenomenon where the onset of puberty is delayed, but the sequence of development is normal. It is often associated with a positive family history and a characteristic delay in **bone age** compared to chronological age. These individuals eventually achieve normal adult height and full sexual maturation without intervention. **Analysis of Incorrect Options:** * **Kallmann Syndrome:** A form of hypogonadotropic hypogonadism (low FSH/LH) associated with anosmia (loss of smell). While a significant cause, it is much rarer than CDGP. * **Klinefelter Syndrome (47, XXY):** The most common cause of **primary hypogonadism** (hypergonadotropic hypogonadism). While it causes small testes and infertility, it usually presents with a normal or slightly delayed *onset* of puberty, but failure of completion. * **Prader-Willi Syndrome:** A genetic disorder (deletion on paternal chromosome 15) characterized by infantile hypotonia, hyperphagia/obesity, and hypogonadotropic hypogonadism. It is a rare syndromic cause of delayed puberty. **Clinical Pearls for NEET-PG:** * **Definition:** Delayed puberty in males is defined as the absence of testicular enlargement (**<4 mL volume** or <2.5 cm length) by **14 years** of age. * **Bone Age:** In CDGP, bone age is delayed and consistent with the height age, whereas in permanent hypogonadism, the discrepancy may be more pronounced. * **First Sign of Puberty (Males):** Testicular enlargement (due to FSH stimulating seminiferous tubules). * **Management:** Reassurance is the mainstay for CDGP. Short-term, low-dose testosterone may be used to "jumpstart" puberty if there is significant psychological distress.

Q: A 7-year-old girl presents with short stature. Examination reveals cubitus valgus, a shield-shaped chest with widely spaced nipples, a webbed neck, and a short 4th metacarpal. What is the most likely clinical diagnosis?

Turner syndrome. **Explanation:** The clinical presentation described is a classic textbook case of **Turner Syndrome (45, XO)**. This condition is the most common sex chromosome abnormality in females, characterized by the complete or partial absence of one X chromosome. **Why Turner Syndrome is correct:** The patient exhibits the hallmark phenotypic features of Turner Syndrome: * **Skeletal findings:** Short stature (most consistent feature), **cubitus valgus** (increased carrying angle of the arm), and a **short 4th metacarpal** (Archibald’s sign). * **Dermatological/Soft tissue:** **Webbed neck** (due to cystic hygroma in utero). * **Thoracic findings:** **Shield-shaped chest** with widely spaced nipples. * **Other common associations:** Bicuspid aortic valve, coarctation of the aorta, and streak ovaries leading to primary amenorrhea. **Why the other options are incorrect:** * **Klinefelter’s Syndrome (47, XXY):** Affects males. Characterized by tall stature, gynecomastia, small firm testes, and infertility. * **Edward Syndrome (Trisomy 18):** Presents with severe intellectual disability, micrognathia, low-set ears, and characteristic **clenched fists** with overlapping fingers. Most do not survive past infancy. * **Patau Syndrome (Trisomy 13):** Presents with midline defects such as cleft lip/palate, holoprosencephaly, polydactyly, and **microphthalmia**. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cardiac defect:** Bicuspid aortic valve (most common overall); Coarctation of the aorta (most specific). * **Renal anomaly:** Horseshoe kidney. * **Karyotype:** 45, XO is most common (50%), but mosaicism (45,X/46,XX) carries a higher risk of gonadoblastoma if Y chromosome material is present. * **Gold Standard Diagnosis:** Chromosomal analysis (Karyotyping).

Question 1

A child presents with severe intellectual disability, a pot-bellied appearance, pale complexion, puffy face, and an enlarged tongue. Dietary deficiency of which of the following substances can lead to this clinical presentation?

Accepted Answer

Iodine

Answer

Calcium

Answer

Iron

Answer

Magnesium

Question 2

What is the treatment for a case of virilizing adrenal hyperplasia?

Accepted Answer

None of these

Answer

Estrogens

Answer

Antiandrogens

Answer

ACTH

Question 3

All of the following may be causes of precocious puberty in girls except?

Accepted Answer

Congenital 21-hydroxylase deficiency

Answer

Hypothalamic hamartoma

Answer

McCune-Albright syndrome

Answer

Granulosa cell tumor of ovary

Question 4

Which of the following represents the triad of signs and symptoms of osteogenesis imperfecta?

Accepted Answer

Blue sclera, brittle bones, opalescent dentin

Answer

Blue sclera, sparse hair, anhydrosis

Answer

Enlarged hands, feet, maxilla, and mandible

Answer

Blue sclera, arachnodactyly, brittle bones

Question 5

What is the inheritance pattern of congenital adrenal hyperplasia?

Accepted Answer

Autosomal Recessive (AR)

Answer

Autosomal Dominant (AD)

Answer

X-linked Dominant (XD)

Answer

X-linked Recessive (XR)

Question 6

A 15-year-old girl presents with short stature, neck webbing, and sexual infantilism. She is also found to have coarctation of the aorta. A chromosomal analysis is likely to demonstrate which of the following?

Accepted Answer

XO karyotype

Answer

Mutation at chromosome 15q21.1

Answer

Trisomy 21

Answer

Defect at chromosome 4p16

Question 7

What is the most common cause of delayed puberty in males?

Accepted Answer

Constitutional delay

Answer

Kallmann syndrome

Answer

Klinefelter syndrome

Answer

Prader-Willi syndrome

Question 8

A 2-year-old child presented with diarrhea and failure to thrive. Blood examination shows Na = 122 mEq/L, K = 6 mEq/L. The child is most probably suffering from which of the following conditions?

Accepted Answer

21-hydroxylase deficiency

Answer

Bartter syndrome

Answer

11-β-hydroxylase deficiency

Answer

17-α-hydroxylase deficiency

Question 9

Clinical manifestations of hoarse cry, umbilical hernia, hypotonia, mottling of skin, and lethargy, with prolonged jaundice, are seen in which condition?

Accepted Answer

Congenital hypothyroidism

Answer

Gaucher's disease

Answer

Mucopolysaccharidosis

Answer

Growth hormone deficiency

Question 10

A 7-year-old girl presents with short stature. Examination reveals cubitus valgus, a shield-shaped chest with widely spaced nipples, a webbed neck, and a short 4th metacarpal. What is the most likely clinical diagnosis?

Accepted Answer

Turner syndrome

Answer

Klinefelter's syndrome

Answer

Edward Syndrome

Answer

Patau syndrome

Endocrinology — MCQs

Endocrinology — MCQs

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