Endocrinology — MCQs
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A 5-year-old boy presents with pubic hair development, being tall, and having increased pigmentation of his genitalia and phallic enlargement, along with a blood pressure of 130/90 mmHg. Measurement of which of the following diagnostic hormones would be most likely to indicate a diagnosis of congenital adrenal hyperplasia?
A 7-day-old newborn presents with vomiting and dehydration. The clinical examination is normal except for hyperpigmentation of the nipple. Electrolyte levels show Na: 120 meq/L and K: 9 meq/L. What is the most likely diagnosis?
What is the most common cause of primary adrenal insufficiency in children?
Retardation of skeletal maturity can be caused by all of the following except:
A boy presented with prolonged jaundice, constipation, and umbilical hernia. What is the probable diagnosis?
Treatment of choice in childhood thyrotoxicosis is:
Which of the following conditions is least likely to present with ambiguous genitalia?
Bone age is advanced in which of the following conditions?
A tentatively female newborn has ambiguous genitalia, with what appears to be a vagina associated with a significantly enlarged clitoris resembling a penis. Other findings include hyponatremia, hyperkalemia, and hypotension. Deficiency of which of the following is suggested by these findings?
Defined by the presence of virilizing signs in girls, select the type of sexual precocity with which it is most likely to be associated:
Endocrinology Indian Medical PG Practice Questions and MCQs
Question 301: A 5-year-old boy presents with pubic hair development, being tall, and having increased pigmentation of his genitalia and phallic enlargement, along with a blood pressure of 130/90 mmHg. Measurement of which of the following diagnostic hormones would be most likely to indicate a diagnosis of congenital adrenal hyperplasia?
- A. Increase 17-hydroxyprogesterone (Correct Answer)
- B. Increase cortisol
- C. Increase aldosterone
- D. Increase 11 deoxycortisol
Explanation: ***Increase 17 beta-hydroxyprogesterone*** - The clinical presentation of **precocious puberty** (pubic hair, phallic enlargement), **hypertension**, and **hyperpigmentation** strongly suggests **congenital adrenal hyperplasia (CAH)**. - In most common forms of CAH (e.g., 21-hydroxylase deficiency), there is an inability to convert **17-hydroxyprogesterone** to 11-deoxycortisol, leading to its significant accumulation. *Increase cortisol* - In CAH due to enzyme deficiencies, the adrenal glands are unable to synthesize sufficient **cortisol**, leading to its **decrease**, not an increase. - The low cortisol then triggers increased **ACTH** release, driving the overproduction of adrenal androgens and precursors. *Increase aldosterone* - Only in specific forms of CAH (e.g., 17-alpha-hydroxylase deficiency) would **aldosterone** be increased (due to shunting of precursors), but this is less common and would typically present with hypokalemia rather than hyperpigmentation. - In the more common 21-hydroxylase deficiency, **aldosterone can be decreased** (salt-wasting form), or normal, leading to hyponatremia and hyperkalemia. *Increase 11-deoxycortisol* - An increase in **11-deoxycortisol** is characteristic of **11-beta-hydroxylase deficiency**, another form of CAH. - While this form also causes **hypertension** and **virilization**, the most prominent precursor elevated in the majority of CAH cases (21-hydroxylase deficiency) is **17-hydroxyprogesterone**.
Question 302: A 7-day-old newborn presents with vomiting and dehydration. The clinical examination is normal except for hyperpigmentation of the nipple. Electrolyte levels show Na: 120 meq/L and K: 9 meq/L. What is the most likely diagnosis?
- A. Primary hypothyroidism
- B. Panhypopituitarism
- C. Pyloric stenosis
- D. Congenital adrenal hyperplasia (Correct Answer)
Explanation: ***Congenital adrenal hyperplasia*** - In **congenital adrenal hyperplasia (CAH)**, particularly 21-hydroxylase deficiency, mineralocorticoid deficiency leads to **salt wasting** with **hyponatremia** and **hyperkalemia**, as seen in this newborn. - **Hyperpigmentation** occurs due to increased ACTH, which also stimulates melanocytes, as a result of cortisol deficiency. *Primary hypothyroidism* - While newborns with primary hypothyroidism can present with feeding difficulties and lethargy, **electrolyte abnormalities** like severe hyponatremia and hyperkalemia are not typical features. - **Hyperpigmentation** is also not a common finding in primary hypothyroidism. *Panhypopituitarism* - **Panhypopituitarism** in a newborn can cause hypoglycemia and other hormone deficiencies, but generally does not present with isolated and severe **salt-wasting crisis** with hyperkalemia, nor isolated nipple hyperpigmentation in this manner. - Multiple trophic hormone deficiencies would be expected, rather than primarily adrenal crisis symptoms. *Pyloric stenosis* - **Pyloric stenosis** typically presents with **non-bilious projectile vomiting** starting around 3-6 weeks of age, not commonly at 7 days, and leads to **hypochloremic alkalosis** with hypokalemia, not hyperkalemia and hyponatremia. - **Hyperpigmentation** is not associated with pyloric stenosis.
Question 303: What is the most common cause of primary adrenal insufficiency in children?
- A. Autoimmune adrenalitis
- B. Adrenal hemorrhage
- C. Congenital adrenal hyperplasia (Correct Answer)
- D. None of the options
Explanation: ***Congenital adrenal hyperplasia*** - **Congenital adrenal hyperplasia (CAH)** is a group of genetic disorders that affect the adrenal glands' ability to produce hormones. - It is the most common cause of **primary adrenal insufficiency** in children, particularly in newborns and infants, due to enzymatic defects like **21-hydroxylase deficiency**. *Autoimmune adrenalitis* - While it is the most common cause of primary adrenal insufficiency (Addison's disease) in adults, **autoimmune adrenalitis** is far less common in children. - Its incidence increases with age, primarily manifesting in **adolescents and adults**. *Adrenal hemorrhage* - **Adrenal hemorrhage** can cause acute adrenal crisis, especially in neonates due to birth trauma or stress, but it is not a common cause of chronic **primary adrenal insufficiency**. - It is typically an acute event rather than a long-term cause of adrenal dysfunction. *None of the options* - This option is incorrect because **Congenital Adrenal Hyperplasia** is a well-established and frequent cause of primary adrenal insufficiency in children.
Question 304: Retardation of skeletal maturity can be caused by all of the following except:
- A. Protein energy malnutrition
- B. Congenital adrenal hyperplasia (Correct Answer)
- C. Hypothyroidism
- D. Chronic renal failure
Explanation: ***Congenital adrenal hyperplasia*** - This condition involves **excessive androgen production**, which can lead to **accelerated skeletal maturity** and premature epiphyseal fusion, rather than retardation. - The increased androgen levels **hasten bone age advancement**, leading to a shorter adult height. *Protein energy malnutrition* - **Severe nutritional deficiencies**, especially of protein and energy, impair growth hormone and IGF-1 axis, leading to **delayed bone growth** and skeletal maturation. - This directly impacts the ability of bones to grow and ossify properly. *Hypothyroidism* - Lack of **thyroid hormones** significantly affects bone development, leading to **delayed epiphyseal ossification** and skeletal maturation. - Thyroid hormones are crucial for normal bone growth and development. *Chronic renal failure* - **Chronic kidney disease** can cause **renal osteodystrophy**, which includes growth retardation and delayed bone age due to disturbances in calcium, phosphate, and vitamin D metabolism. - It also affects growth hormone sensitivity and IGF-1 production.
Question 305: A boy presented with prolonged jaundice, constipation, and umbilical hernia. What is the probable diagnosis?
- A. Growth hormone deficiency
- B. Kernicterus
- C. Congenital adrenal hyperplasia
- D. Congenital hypothyroidism (Correct Answer)
Explanation: ***Congenital hypothyroidism*** - **Prolonged jaundice** is a common and early sign in congenital hypothyroidism due to delayed bilirubin conjugation and excretion. - **Constipation** and an **umbilical hernia** are classic features, reflecting decreased gut motility and weak abdominal muscles associated with thyroid hormone deficiency. *Growth hormone deficiency* - Primarily presents with **short stature** and delayed bone age, not typically with prolonged jaundice or umbilical hernia in infancy. - While it can be associated with some developmental delays, the combination of signs in the question points away from this diagnosis. *Kernicterus* - This is a neurological consequence of **untreated severe hyperbilirubinemia**, leading to brain damage, not a primary cause of jaundice itself. - While prolonged jaundice is present, kernicterus would manifest with severe neurological symptoms like lethargy, poor feeding, and opisthotonus, not umbilical hernia. *Congenital adrenal hyperplasia* - Presents due to deficiencies in adrenal steroid synthesis, leading to **ambiguous genitalia** in females and **salt-wasting crises** in classic forms. - It does not typically cause prolonged jaundice or umbilical hernia as primary manifestations.
Question 306: Treatment of choice in childhood thyrotoxicosis is:
- A. Carbimazole (Correct Answer)
- B. Radioiodine therapy
- C. Surgical intervention
- D. Lugol's iodine solution
Explanation: ***Carbimazole*** - **Antithyroid medications** like carbimazole are the **first-line treatment** for childhood thyrotoxicosis due to their efficacy in controlling hormone levels and lower risk compared to other interventions. - It works by inhibiting the synthesis of **thyroid hormones**, allowing for a gradual resolution of symptoms. *Radioiodine therapy* - This treatment is generally avoided in children due to potential long-term risks, including an increased risk of **thyroid cancer** and the need for lifelong **thyroid hormone replacement**. - It is typically reserved for older adolescents or cases where other treatments have failed. *Surgical intervention* - **Thyroidectomy** is usually considered a last resort in children due to the risks associated with surgery, such as damage to the **parathyroid glands** or **recurrent laryngeal nerve**. - It may be indicated in cases of very large goiter, drug intolerance, or non-compliance with medical therapy. *Lugol's iodine solution* - **Lugol's iodine** is primarily used for **short-term preparation** before thyroid surgery to decrease the vascularity of the gland and in **thyroid storm** to block hormone release. - It is not a definitive long-term treatment for childhood thyrotoxicosis due to its transient effect and potential for rebound hyperthyroidism.
Question 307: Which of the following conditions is least likely to present with ambiguous genitalia?
- A. Hermaphroditism
- B. Super female (47 XXX) (Correct Answer)
- C. Gonadal dysgenesis
- D. Gonadal agenesis
Explanation: ***Super female (47 XXX)*** - Individuals with **47,XXX syndrome**, often called "triple X syndrome," typically have a **normal female phenotype** and are not usually born with ambiguous genitalia. - While they may have some developmental differences or fertility issues, their external genitalia are typically **unambiguously female**. *Gonadal dysgenesis* - This condition involves **abnormal development of the gonads**, leading to a spectrum of presentations that can include **ambiguous genitalia**. - Incomplete differentiation of the testes or ovaries can result in external genitalia that are neither definitively male nor female. *Hermaphroditism* - **True hermaphroditism** (now referred to as **ovotesticular disorder of sex development**) is characterized by the presence of **both ovarian and testicular tissue** in the same individual. - This condition almost always results in **ambiguous external genitalia** because the sex hormone production is mixed. *Gonadal agenesis* - **Gonadal agenesis** refers to the **complete absence of gonads**, which can lead to ambiguous genitalia, particularly if gonadal development failed before external genitalia differentiation. - Without the hormones produced by the gonads (e.g., androgens from testes), the development of male external genitalia is impaired, leading to **under-masculinization** or ambiguous features.
Question 308: Bone age is advanced in which of the following conditions?
- A. Congenital adrenal hyperplasia (Correct Answer)
- B. Hypothyroidism
- C. Hypopituitarism
- D. Constitutional delay in growth
Explanation: ***Congenital adrenal hyperplasia*** - In **congenital adrenal hyperplasia (CAH)**, the adrenal glands produce excessive androgens, leading to precocious puberty and **accelerated skeletal maturation**, thus advancing bone age. - The excess androgens cause early fusion of the **epiphyseal growth plates**, leading to a disproportionately taller stature in childhood but potentially shorter adult height. *Hypothyroidism* - **Hypothyroidism** causes delayed growth and development, including **delayed bone age**, due to insufficient thyroid hormone which is crucial for normal skeletal maturation. - Children with hypothyroidism typically have shorter stature for their chronological age and delayed ossification of epiphyses. *Hypopituitarism* - **Hypopituitarism**, especially growth hormone deficiency, leads to **delayed bone age** and significantly stunted growth because growth hormone is essential for normal skeletal development. - Insufficient growth hormone results in slower epiphyseal growth and delayed growth plate closure. *Constitutional delay in growth* - **Constitutional delay in growth and puberty** is characterized by a "late bloomer" pattern, where both linear growth and pubertal development are delayed, resulting in a **delayed bone age**. - These children typically have normal growth velocity for their bone age and will eventually reach a normal adult height, just later than their peers.
Question 309: A tentatively female newborn has ambiguous genitalia, with what appears to be a vagina associated with a significantly enlarged clitoris resembling a penis. Other findings include hyponatremia, hyperkalemia, and hypotension. Deficiency of which of the following is suggested by these findings?
- A. 17-Hydroxylase deficiency
- B. 21-Hydroxylase deficiency (Correct Answer)
- C. 3β-Hydroxysteroid dehydrogenase deficiency
- D. 11-Hydroxylase deficiency
Explanation: ***21-Hydroxylase deficiency*** * This is the most common cause of **congenital adrenal hyperplasia (CAH)**, leading to a deficiency in cortisol and aldosterone production, and an excess of adrenal androgens. * The absence of **aldosterone** leads to **salt wasting**, presenting as hyponatremia and hyperkalemia, and potentially contributing to hypotension. The excess androgens cause **virilization** in genetic females, resulting in ambiguous genitalia like an enlarged clitoris. *17-Hydroxylase deficiency* * This deficiency leads to reduced production of **androgens**, estrogens, and cortisol, with an *excess* of mineralocorticoids. * Genetic females would typically present with **normal internal and external genitalia**, while genetic males would have ambiguous genitalia or female external genitalia due to insufficient androgen synthesis. It would also lead to hypertension due to mineralocorticoid excess, not hypotension. *3β-Hydroxysteroid dehydrogenase deficiency* * This deficiency impairs the synthesis of **cortisol**, aldosterone, and androgens, leading to a generalized steroid synthesis defect. * It causes both 46,XX females and 46,XY males to have **ambiguous genitalia**, but unlike 21-hydroxylase deficiency, it also results in a lack of dihydrotestosterone in males leading to undervirilization. *11-Hydroxylase deficiency* * This deficiency causes decreased production of **cortisol and aldosterone**, but leads to an *accumulation of 11-deoxycorticosterone*, which has mineralocorticoid activity. * This accumulation often results in **hypertension and hypokalemia**, which contradicts the patient's presentation of hypotension and hyperkalemia. It also leads to virilization in females due to increased androgen production.
Question 310: Defined by the presence of virilizing signs in girls, select the type of sexual precocity with which it is most likely to be associated:
- A. True sexual precocity
- B. Incomplete sexual precocity
- C. Isosexual precocious pseudopuberty
- D. Heterosexual precocious pseudopuberty (Correct Answer)
Explanation: ***Heterosexual precocious pseudopuberty*** - This condition is characterized by signs of sexual development that are **inconsistent with the genetic sex** of the individual, such as **virilization in girls**. - It occurs due to the presence of **androgens** from sources like adrenal tumors or congenital adrenal hyperplasia, leading to male secondary sexual characteristics in a genetically female individual. *True sexual precocity* - Involves the **premature activation of the hypothalamic-pituitary-gonadal (HPG) axis**, leading to the development of secondary sexual characteristics appropriate for the individual's genetic sex (e.g., breast development and pubic hair in girls). - This typically results in **isosexual precocity**, meaning the development of characteristics consistent with the child's own sex. *Incomplete sexual precocity* - Refers to the isolated development of a **single secondary sexual characteristic**, such as premature thelarche (breast development without other signs) or premature adrenarche (pubic or axillary hair development without other signs). - It does not involve the full constellation of virilizing signs in a girl. *Isosexual precocious pseudopuberty* - This condition involves the development of secondary sexual characteristics **appropriate for the individual's genetic sex**, but it is caused by **gonadal or adrenal tumors or exogenous steroids**, not by activation of the HPG axis. - In girls, this would manifest as early breast development and vaginal bleeding, not virilization.
Practice by Chapter
Disorders of Growth
Practice Questions
Thyroid Disorders
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Disorders of Puberty
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Adrenal Disorders
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Diabetes Mellitus in Children
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Disorders of Calcium and Phosphate Metabolism
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Disorders of Sexual Development
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Hypoglycemia
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Obesity and Metabolic Syndrome
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Pituitary Disorders
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Multiple Endocrine Neoplasia Syndromes
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Endocrine Emergencies
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