Endocrinology Practice Questions

Q: In a patient with Turner syndrome (45, XO), what is the recommended hormone replacement therapy (HRT)?

Growth hormone + E+P. ***Growth hormone + E+P*** - **Growth hormone** is essential to improve final adult height in girls with Turner syndrome, as they commonly experience **short stature**. - **Estrogen (E)** and **progesterone (P)** replacement is crucial for the development of **secondary sexual characteristics** and to prevent long-term complications of estrogen deficiency, such as osteoporosis. *Estrogen* - While **estrogen** is a component of HRT for Turner syndrome, it is insufficient on its own for comprehensive management. - **Progesterone** is also necessary to induce cyclic bleeding and protect the uterine lining from unchecked estrogenic stimulation. *No HRT Needed* - This is incorrect as **HRT is medically necessary** for almost all individuals with Turner syndrome due to **gonadal dysgenesis** and resultant estrogen deficiency. - Without HRT, patients would not develop secondary sexual characteristics, would be at high risk for osteoporosis, and experience other long-term health issues. *HRT only after 45 years* - This is incorrect as HRT should be initiated much earlier, typically in **early adolescence** (around 12-14 years old), to mimic natural puberty. - Delaying HRT would prevent the development of secondary sexual characteristics and lead to significant **bone mineral density loss** during critical developmental years.

Q: Which of the following conditions is most commonly associated with hypocalcemia in a child?

Vitamin D deficiency. ***Vitamin D deficiency*** - **Vitamin D deficiency** is the **most common cause** of hypocalcemia in the pediatric population worldwide, particularly in developing countries and at-risk populations (limited sun exposure, dark skin, exclusive breastfeeding without supplementation). - **Vitamin D** is crucial for **intestinal calcium absorption** and bone mineralization. - Severe deficiency leads to **rickets** and **hypocalcemia** due to impaired calcium uptake, with compensatory secondary hyperparathyroidism. *DiGeorge syndrome with normal parathyroid function* - **DiGeorge syndrome** (22q11.2 deletion) classically causes **hypocalcemia** due to **parathyroid hypoplasia or aplasia**, resulting in hypoparathyroidism. - However, **if parathyroid function is explicitly stated as normal**, the syndrome would NOT cause hypocalcemia, making this option incorrect as written. - The qualifier "with normal parathyroid function" is key—it eliminates the mechanism by which DiGeorge causes hypocalcemia. *Magnesium deficiency* - Severe **magnesium deficiency** can cause **hypocalcemia** by impairing **PTH secretion** and inducing **skeletal resistance to PTH**. - However, it is **uncommon** as a primary cause of hypocalcemia in the general pediatric population compared to vitamin D deficiency. *Hypoparathyroidism* - **Hypoparathyroidism** results in reduced **PTH levels**, leading to decreased renal calcium reabsorption and reduced vitamin D activation, causing **hypocalcemia**. - While it **directly** causes hypocalcemia, it is a **less common** condition than vitamin D deficiency in the general pediatric population, making vitamin D deficiency the most frequent cause overall.

Q: Which of the following is the MOST characteristic cause of precocious puberty?

McCune-Albright syndrome. ***McCune-Albright syndrome*** - This syndrome is characterized by the **classic triad** of **fibrous dysplasia of bone**, **café-au-lait spots**, and **precocious puberty**. - It causes **peripheral (gonadotropin-independent) precocious puberty** due to **activating mutation in the GNAS gene**, leading to autonomous hormone production. - This is one of the **most characteristic and well-defined causes** of peripheral precocious puberty in pediatric endocrinology. *Hypothyroidism* - **Severe, long-standing primary hypothyroidism** can paradoxically cause precocious puberty (Van Wyk-Grumbach syndrome). - This occurs due to **receptor overlap** between TSH and gonadotropin receptors, but it is a **much rarer cause**. - Typically presents with **delayed bone age** (unlike typical precocious puberty which has advanced bone age). *CNS irradiation* - Cranial irradiation can cause **central precocious puberty** by damaging hypothalamic-pituitary axis. - However, it is an **acquired iatrogenic cause** rather than a primary disease entity classically associated with precocious puberty. - More commonly causes **growth hormone deficiency** and other endocrine deficits. *None of the options* - Incorrect, as McCune-Albright syndrome is a well-established, characteristic cause of precocious puberty.

Q: Turner syndrome is maximally associated with ?

Coarctation of aorta. **Coarctation of aorta** - **Coarctation of the aorta** is the most common cardiovascular abnormality associated with **Turner syndrome**, occurring in 5-20% of affected individuals [1]. - It is a **narrowing of the aorta**, typically near the ductus arteriosus, which can lead to hypertension and other cardiovascular complications [1]. *Horseshoe kidney* - While **renal anomalies** are common in Turner syndrome (occurring in 30-60%), **horseshoe kidney** is not the single most prevalent or *maximally associated* malformation. - Other renal abnormalities like duplicated collecting systems and pelvic kidneys are also frequently observed. *VSD* - **Ventricular septal defect (VSD)** is a type of congenital heart defect, but it is not as frequently associated with Turner syndrome as coarctation of the aorta [2]. - VSDs are among the most common congenital heart defects overall but are not the leading cardiovascular anomaly specific to Turner syndrome [3]. *ASD* - **Atrial septal defect (ASD)** is another congenital heart anomaly, but it is not the *maximally associated* cardiovascular defect in Turner syndrome. - Coarctation of the aorta and bicuspid aortic valve are more characteristic cardiovascular findings in this condition [1].

Q: Which condition is associated with congenital adrenal hyperplasia?

Female pseudohermaphroditism. ***Female pseudohermaphroditism*** - In **21-hydroxylase deficiency**, the most common form of CAH, virilization of a female fetus occurs due to excessive **androgen production** [2], [3]. - This leads to ambiguous genitalia in genetically female (XX) infants, presenting as **female pseudohermaphroditism** [2]. *Male pseudohermaphroditism* - This condition occurs when a **genetically male individual (XY)** has external genitalia that are undervirilized or ambiguous. - It is typically caused by inadequate **androgen synthesis** or action, such as in **androgen insensitivity syndrome**, which is not the primary presentation of CAH [2]. *True pseudohermaphroditism* - This term refers to individuals who possess both **ovarian and testicular tissue**, either in separate gonads or as ovotestes [1], [2]. - It is distinct from CAH, where gonadal tissue is uniform (either ovaries or testes), but the external genitalia are ambiguous due to hormonal imbalances [2]. *Sequential pseudohermaphroditism* - This term is not a recognized medical classification for conditions like CAH. - It does not describe a specific developmental anomaly of the reproductive system related to adrenal function.

Q: Which of the following is true regarding precocious puberty:

Sexual maturity is attained early. ***Sexual maturity is attained early*** - **Precocious puberty** is defined by the development of secondary sexual characteristics significantly earlier than the average age. - This early onset of puberty means that affected individuals reach **sexual maturity** at a younger chronological age. *Mental function is increased* - Precocious puberty does not inherently lead to an increase in **mental function** or cognitive abilities. - While hormonal changes can influence mood and behavior, they do not enhance intelligence. *Reproductive function is absent* - Precocious puberty implies the premature activation of the **hypothalamic-pituitary-gonadal axis**, leading to the appearance of secondary sexual characteristics and, in many cases, the potential for **reproductive function**. - Girls, for example, can experience early menarche and boys can produce sperm, meaning fertility is not absent but rather accelerated. *Body proportions remain unchanged* - Precocious puberty often results in changes in **body proportions**, particularly due to the early closure of epiphyseal plates. - Although there is an initial growth spurt, the premature fusion of growth plates can lead to a shorter-than-average adult height.

Q: What is the mode of inheritance for the most common form of hypophosphatemic rickets?

X-Linked Dominant (XD). ***X-Linked Dominant (XD)*** - The most common form of hypophosphatemic rickets is **X-linked hypophosphatemic rickets (XLH)**, which is inherited in an X-linked dominant pattern. - This condition is caused by mutations in the **PHEX gene** on the X chromosome, leading to impaired phosphate reabsorption in the kidneys. *Autosomal Recessive (AR)* - While some rare forms of hypophosphatemic rickets exist with **autosomal recessive** inheritance, they are not the most common. - These forms typically involve mutations in genes affecting phosphate transport or vitamin D metabolism, distinct from the primary defect in XLH. *Autosomal Dominant (AD)* - There are also rare **autosomal dominant** forms of hypophosphatemic rickets, such as hereditary hypophosphatemic rickets with hypercalciuria (HHRH) or autosomal dominant hypophosphatemic rickets (ADHR). - However, these are less common than the X-linked dominant form (XLH). *X-Linked Recessive (XR)* - **X-linked recessive** inheritance typically affects males more severely and exclusively, with carrier females usually unaffected or mildly affected. - In X-linked dominant conditions like XLH, both males and females are affected, though females may exhibit variable expressivity.

Q: Which of the following is not a feature of hypothyroidism in infancy?

Premature closure of posterior fontanelle. ***Premature closure of posterior fontanelle*** - Delayed closure of fontanelles, particularly the **posterior fontanelle**, is a characteristic feature of **congenital hypothyroidism** due to impaired bone maturation. - Therefore, **premature closure** would be inconsistent with a diagnosis of hypothyroidism in infancy. *Coarse facies* - **Coarse facial features** such as a broad nasal bridge, puffy eyelids, and a protuberant tongue are common manifestations of **congenital hypothyroidism** due to the accumulation of glycosaminoglycans. - This is a direct consequence of the metabolic derangements caused by insufficient thyroid hormone. *Umbilical hernia* - An **umbilical hernia** is frequently observed in infants with hypothyroidism, resulting from generalized **hypotonia** and incomplete closure of the umbilical ring. - The reduced muscle tone characteristic of the condition contributes to this physical finding. *Constipation* - **Constipation** is a common gastrointestinal symptom in infants with hypothyroidism, caused by **decreased gut motility** secondary to reduced thyroid hormone levels. - This is a clinical indicator of the systemic metabolic slowing associated with the condition.

Q: What is the target HbA1c level for a 2-5 year old child with diabetes mellitus (DM)?

< 8 %. ***< 8 %*** - For children aged 2-5 years with diabetes, the current **ADA (American Diabetes Association) 2024 Standards of Care** recommend a target HbA1c of **< 8%** to balance optimal glycemic control with safety. - This target acknowledges the challenges of managing glucose levels in very young children, including their **inconsistent eating patterns**, difficulty communicating hypoglycemic symptoms, and **increased risk of severe hypoglycemia** which can impair neurodevelopment. - The target prioritizes **safety** while still promoting good metabolic control to prevent long-term diabetic complications. *< 7 %* - A target HbA1c of **< 7%** is typically recommended for **older adolescents and adults** with diabetes who can recognize and manage hypoglycemic symptoms more effectively. - This stringent target is often challenging and potentially dangerous for young children aged 2-5 years, significantly increasing the risk of **frequent and severe hypoglycemic episodes** which can have long-term neurocognitive consequences. *< 9 %* - While a target of < 9% may have been recommended in **older guidelines**, it is now considered **too lenient** for children aged 2-5 years according to current evidence-based recommendations. - Current guidelines advocate for **< 8%** as it provides better long-term glycemic control without substantially increasing hypoglycemia risk when diabetes is managed appropriately with modern insulin regimens and monitoring technologies. *< 6 %* - A target HbA1c of **< 6%** is considered very aggressive and is rarely recommended for any pediatric age group, especially not for young children with diabetes. - Achieving such a low target would require intensive insulin regimens, leading to an unacceptably high risk of **severe hypoglycemia**, impaired quality of life, and potential neurodevelopmental harm in this vulnerable age group.

Q: In Precocious puberty, the age limit for girls is?

8 years. ***8 years*** - Precocious puberty is defined clinically by the development of secondary sexual characteristics in girls before the age of **8 years old**. - This age cut-off is based on population studies and clinical consensus to identify children needing further evaluation for underlying causes. *10 years* - This age is generally considered within the **normal range** for the onset of puberty, not precocious. - Pubertal development typically begins between ages 8 and 13 in girls. *9 years* - While close to the precocious threshold, **9 years** is still considered within the typical window for the onset of puberty. - The established clinical definition for precocious puberty in girls is explicitly _before_ the age of 8. *11 years* - This age is well within the **normal range** for pubertal onset and progression in girls. - Development of secondary sexual characteristics at this age would not be considered precocious.

Question 1

In a patient with Turner syndrome (45, XO), what is the recommended hormone replacement therapy (HRT)?

Accepted Answer

Growth hormone + E+P

Answer

No HRT Needed

Answer

HRT only after 45 years

Answer

Estrogen

Question 2

Which of the following conditions is most commonly associated with hypocalcemia in a child?

Accepted Answer

Vitamin D deficiency

Answer

DiGeorge syndrome with normal parathyroid function

Answer

Magnesium deficiency

Answer

Hypoparathyroidism

Question 3

Which of the following is the MOST characteristic cause of precocious puberty?

Accepted Answer

McCune-Albright syndrome

Answer

Hypothyroidism

Answer

CNS irradiation

Answer

None of the options

Question 4

Turner syndrome is maximally associated with ?

Accepted Answer

Coarctation of aorta

Answer

Horseshoe kidney

Answer

VSD

Answer

ASD

Question 5

Which condition is associated with congenital adrenal hyperplasia?

Accepted Answer

Female pseudohermaphroditism

Answer

Male pseudohermaphroditism

Answer

True pseudohermaphroditism

Answer

Sequential pseudohermaphroditism

Question 6

Which of the following is true regarding precocious puberty:

Accepted Answer

Sexual maturity is attained early

Answer

Mental function is increased

Answer

Reproductive function is absent

Answer

Body proportions remain unchanged

Question 7

What is the mode of inheritance for the most common form of hypophosphatemic rickets?

Accepted Answer

X-Linked Dominant (XD)

Answer

Autosomal Recessive (AR)

Answer

Autosomal Dominant (AD)

Answer

X-Linked Recessive (XR)

Question 8

Which of the following is not a feature of hypothyroidism in infancy?

Accepted Answer

Premature closure of posterior fontanelle

Answer

Umbilical hernia

Answer

Constipation

Answer

Coarse facies

Question 9

What is the target HbA1c level for a 2-5 year old child with diabetes mellitus (DM)?

Accepted Answer

< 8 %

Answer

< 7 %

Answer

< 9 %

Answer

< 6 %

Question 10

In Precocious puberty, the age limit for girls is?

Accepted Answer

8 years

Answer

10 years

Answer

9 years

Answer

11 years

Endocrinology — MCQs

Endocrinology — MCQs

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