Endocrinology Practice Questions

Q: 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?

Increase 17-hydroxyprogesterone. ***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**.

Q: 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?

Congenital adrenal hyperplasia. ***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.

Q: What is the most common cause of primary adrenal insufficiency in children?

Congenital adrenal hyperplasia. ***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.

Q: Retardation of skeletal maturity can be caused by all of the following except:

Congenital adrenal hyperplasia. ***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.

Q: A boy presented with prolonged jaundice, constipation, and umbilical hernia. What is the probable diagnosis?

Congenital hypothyroidism. ***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.

Q: Treatment of choice in childhood thyrotoxicosis is:

Carbimazole. ***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.

Q: Which of the following conditions is least likely to present with ambiguous genitalia?

Super female (47 XXX). ***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.

Q: Bone age is advanced in which of the following conditions?

Congenital adrenal hyperplasia. ***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.

Q: 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?

21-Hydroxylase deficiency. ***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.

Q: Defined by the presence of virilizing signs in girls, select the type of sexual precocity with which it is most likely to be associated:

Heterosexual precocious pseudopuberty. ***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.

Question 1

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?

Accepted Answer

Increase 17-hydroxyprogesterone

Answer

Increase cortisol

Answer

Increase aldosterone

Answer

Increase 11 deoxycortisol

Question 2

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?

Accepted Answer

Congenital adrenal hyperplasia

Answer

Primary hypothyroidism

Answer

Panhypopituitarism

Answer

Pyloric stenosis

Question 3

What is the most common cause of primary adrenal insufficiency in children?

Accepted Answer

Congenital adrenal hyperplasia

Answer

Autoimmune adrenalitis

Answer

Adrenal hemorrhage

Answer

None of the options

Question 4

Retardation of skeletal maturity can be caused by all of the following except:

Accepted Answer

Congenital adrenal hyperplasia

Answer

Protein energy malnutrition

Answer

Hypothyroidism

Answer

Chronic renal failure

Question 5

A boy presented with prolonged jaundice, constipation, and umbilical hernia. What is the probable diagnosis?

Accepted Answer

Congenital hypothyroidism

Answer

Growth hormone deficiency

Answer

Kernicterus

Answer

Congenital adrenal hyperplasia

Question 6

Treatment of choice in childhood thyrotoxicosis is:

Accepted Answer

Carbimazole

Answer

Radioiodine therapy

Answer

Surgical intervention

Answer

Lugol's iodine solution

Question 7

Which of the following conditions is least likely to present with ambiguous genitalia?

Accepted Answer

Super female (47 XXX)

Answer

Hermaphroditism

Answer

Gonadal dysgenesis

Answer

Gonadal agenesis

Question 8

Bone age is advanced in which of the following conditions?

Accepted Answer

Congenital adrenal hyperplasia

Answer

Hypothyroidism

Answer

Hypopituitarism

Answer

Constitutional delay in growth

Question 9

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?

Accepted Answer

21-Hydroxylase deficiency

Answer

17-Hydroxylase deficiency

Answer

3β-Hydroxysteroid dehydrogenase deficiency

Answer

11-Hydroxylase deficiency

Question 10

Defined by the presence of virilizing signs in girls, select the type of sexual precocity with which it is most likely to be associated:

Accepted Answer

Heterosexual precocious pseudopuberty

Answer

True sexual precocity

Answer

Incomplete sexual precocity

Answer

Isosexual precocious pseudopuberty

Endocrinology — MCQs

Endocrinology — MCQs

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