Endocrinology Practice Questions

Q: Precocious puberty in a girl is defined as breast development before the age of?

8 years. ***8 years*** - **Precocious puberty** in girls is traditionally defined as the development of secondary sexual development, such as **breast development** (thelarche), before the age of **8 years** [1]. - This age cut-off is based on population studies identifying when pubertal changes typically begin in the majority of girls, though studies suggest earlier onset in some populations [1]. *10 years* - This age is outside the typical definition for **precocious puberty** in girls, as most girls will have begun puberty by this age [2]. - Development of breasts at 10 years would generally be considered within the **normal range** of pubertal onset, which is typically between 8 to 13 years [2]. *6 years* - While **puberty at 6 years** would certainly be classified as precocious, the general definition uses **8 years** as the boundary [1]. - Puberty occurring before 6 years would be considered **very early precocious puberty** and warrant thorough investigation; however, benign premature thelarche is most common between 6 months and 3 years [3]. *12 years* - Pubertal development at 12 years is well within the **normal range** for female puberty [2]. - This age is frequently associated with the onset of **menarche** (first menstruation) rather than initial breast development.

Q: Hypocalcemia in a child may be associated with

All of the options. ***All of the options*** - **Hypocalcemia** can stem from various causes, and all the listed conditions (DiGeorge syndrome, magnesium deficiency, and hypoparathyroidism) are known to cause it. - A comprehensive understanding of potential etiologies is crucial for accurate diagnosis and treatment of hypocalcemia in children. *Digeorge syndrome* - **DiGeorge syndrome** is a genetic disorder associated with abnormal development of the **thymus** and **parathyroid glands**, leading to **hypoparathyroidism** and subsequent hypocalcemia. - This condition is characterized by a deletion on **chromosome 22q11.2**, resulting in various clinical manifestations including **cardiac defects** and **immune deficiencies**. *Magnesium deficiency* - **Magnesium deficiency (hypomagnesemia)** can impair the release of **parathyroid hormone (PTH)** and reduce target organ responsiveness to PTH, leading to **hypocalcemia**. - Adequate magnesium levels are essential for the proper functioning of the **parathyroid glands** and calcium homeostasis. *Hypoparathyroidism* - **Hypoparathyroidism** is a condition where the **parathyroid glands** produce insufficient amounts of **parathyroid hormone (PTH)**, which is crucial for regulating calcium levels. - Insufficient PTH leads to decreased reabsorption of calcium in the kidneys and reduced calcium release from bones, resulting in **hypocalcemia**.

Q: Following are the features of cretinism, except

Normal intelligence. ***Normal intelligence*** - **Cretinism** (congenital hypothyroidism) is characterized by **severe mental retardation** if left untreated during critical developmental periods. - Normal intelligence is **not** a feature; rather, impaired cognitive development is a hallmark of the condition. *Characteristic facial features* - Patients with cretinism often present with **coarse facial features**, including a **puffy face**, broad nose, and thick lips. - These distinct features are a diagnostic clue for untreated congenital hypothyroidism. *Pot — belly* - A **protuberant abdomen** (pot-belly) is a common sign in infants and children with cretinism. - This is often accompanied by **umbilical hernia** due to generalized hypotonia. *Stunted growth* - **Dwarfism** or severely stunted growth is a prominent feature of cretinism due to the critical role of thyroid hormones in skeletal development and linear growth. - Delayed bone maturation and short stature are expected.

Q: Congenital adrenal hyperplasia is the most common cause of

Female pseudohermaphroditism (androgenized female 46XX). ***Female pseudohermaphroditism (androgenized female 46XX)*** - Congenital adrenal hyperplasia (CAH), particularly **21-hydroxylase deficiency**, leads to overproduction of **adrenal androgens**. [3] - In a 46,XX fetus, this excess androgen exposure results in masculinization of external genitalia, while internal female organs (uterus, ovaries) are present, defining **female pseudohermaphroditism**. [3] *True hermaphroditism* - Characterized by the presence of both **ovarian and testicular tissue** in the same individual. [2] - This condition is rare and not directly caused by the hormonal imbalances seen in CAH. *Male pseudohermaphroditism (underandrogenized male 46XY)* - Occurs in individuals with a **46,XY karyotype** who have testes but whose external genitalia are ambiguous or female due to **insufficient androgen production or action**. - Conditions like **androgen insensitivity syndrome** or defects in testosterone synthesis cause this, not CAH. [3] *Turner's syndrome* - A chromosomal disorder with a **45,XO karyotype**, primarily affecting females. [1] - It is characterized by features such as **short stature**, gonadal dysgenesis (streak gonads), and various congenital anomalies, and it is not a form of pseudohermaphroditism related to adrenal function. [1]

Q: Treatment for childhood hypothyroidism is with -

Levothyroxine. ***Correct: Levothyroxine*** - **Levothyroxine** is synthetic **thyroxine (T4)**, the standard hormone replacement therapy for childhood hypothyroidism - It is **well-absorbed orally**, has a **long half-life**, and provides stable thyroid hormone levels - Once administered, it is converted to **T3 (the active form)** in peripheral tissues, ensuring steady thyroid hormone supply - **Preferred in children** for consistent growth and neurodevelopment *Incorrect: TSH* - **TSH (Thyroid-Stimulating Hormone)** is produced by the pituitary gland to stimulate thyroid hormone production - In **primary hypothyroidism**, TSH levels are *elevated* due to lack of negative feedback - TSH is a **diagnostic marker**, not a therapeutic agent for hormone replacement *Incorrect: Propylthiouracil* - **Propylthiouracil** is an **anti-thyroid drug** used to treat **hyperthyroidism** (excessive thyroid hormone) - It works by *inhibiting* thyroid hormone synthesis - Using it in hypothyroidism would **worsen** the condition by further reducing thyroid hormone levels *Incorrect: T3* - **T3 (triiodothyronine)** is the more metabolically active form of thyroid hormone - It has a **shorter half-life** and causes more **fluctuating hormone levels** - **Not preferred** for long-term replacement in children due to difficulty maintaining stable levels - Most levothyroxine (T4) is naturally converted to T3 *in vivo*, providing adequate T3 without direct supplementation

Q: A five year old boy presents with precocious puberty and a Blood pressure of 130/80 mm Hg. Estimation of which of the following will help in diagnosis

17 hydroxy - progesterone. ***17 hydroxy - progesterone*** - Precocious puberty with hypertension suggests a form of **congenital adrenal hyperplasia (CAH)**, specifically 11β-hydroxylase deficiency or 21-hydroxylase deficiency. - While **17-hydroxyprogesterone** is highly elevated in 21-hydroxylase deficiency, its levels also rise in 11β-hydroxylase deficiency due to the block in cortisol synthesis leading to increased ACTH stimulation. *Cortisol* - **Cortisol** levels are typically low or normal in CAH due to enzyme deficiencies blocking its synthesis, but measuring cortisol directly is not the primary diagnostic test. - The elevated blood pressure is due to accumulation of precursor steroids with mineralocorticoid activity, not directly due to high cortisol. *11-deoxycortisol* - **11-deoxycortisol** (compound S) is a precursor that accumulates specifically in **11β-hydroxylase deficiency**, leading to hypertension and precocious puberty. - While it's a key marker for this specific type of CAH, 17-hydroxyprogesterone is a broader initial screening marker as it is elevated in both 21-hydroxylase and 11β-hydroxylase deficiencies, which are the most common forms leading to these symptoms. *Aldosterone* - **Aldosterone** levels are usually low in both 21-hydroxylase and 11β-hydroxylase deficiencies, often contributing to salt wasting in the salt-wasting form of 21-hydroxylase deficiency. - Although the patient has hypertension, it is caused by the accumulation of other mineralocorticoid-like precursors, not elevated aldosterone.

Q: Association of sexual precocity, multiple cystic bone lesions and endocrinopathies are seen in:

McCune-Albright's syndrome. ***McCune-Albright's syndrome*** - This syndrome is characterized by the classic triad of **precocious puberty**, **polyostotic fibrous dysplasia** (multiple cystic bone lesions), and **café-au-lait spots**. - It is caused by a somatic activating mutation in the **GNAS1 gene**, leading to constitutive activation of G protein-coupled receptors in affected tissues, resulting in hormonal overproduction and dysplastic changes. *Hepatoblastoma* - Hepatoblastoma is a **malignant liver tumor** primarily affecting infants and children. - While it can, in rare cases, produce human chorionic gonadotropin (hCG) causing precocious puberty, it is not typically associated with widespread cystic bone lesions or other endocrinopathies characteristic of McCune-Albright's. *Androblastoma* - An androblastoma (also known as a **Sertoli-Leydig cell tumor**) is a rare **gonadal stromal tumor** that secretes androgens. - It can cause **virilization** and, in prepubertal girls, precocious puberty, but it does not cause multiple cystic bone lesions or other systemic endocrine disorders as seen in McCune-Albright's. *Granulosa cell tumor* - Granulosa cell tumors are **ovarian stromal tumors** that can produce **estrogen**, leading to precocious puberty in young girls. - While they are a cause of precocious puberty, they do not typically present with the extensive cystic bone lesions or the full spectrum of endocrinopathies found in McCune-Albright's syndrome.

Q: A one-year-old child presents with short stature, lethargy, and constipation. Clinical examination shows a palpable goiter. Laboratory investigations revealed a low T4 and elevated TSH. Which of the following is the most likely diagnosis?

Thyroid Dyshormonogenesis. ***Thyroid Dyshormonogenesis*** - This condition involves a defect in the **synthesis of thyroid hormones**, leading to **hypothyroidism** despite a physically normal or enlarged gland (goiter). - The combination of **goiter (palpable)** with **low T4** and **elevated TSH** in an infant points to the thyroid gland's inability to produce hormones effectively, prompting increased TSH stimulation. *Central Hypothyroidism* - Characterized by **low TSH** (or inappropriately normal TSH) alongside **low T4**, indicating a problem with the pituitary or hypothalamus. - A **goiter would not typically be present** as the thyroid gland is not being excessively stimulated; the child presents with an elevated TSH. *Thyroid Dysgenesis* - This typically presents with an **absent or underdeveloped thyroid gland**, meaning a **goiter would not be palpable**. - While it causes **low T4** and **elevated TSH**, the presence of a palpable goiter rules out dysgenesis. *TSH Receptor Blocking Antibody* - These antibodies block the TSH receptor, leading to **atrophic thyroiditis** and **hypothyroidism**, but typically without a goiter. - The thyroid gland is unable to respond to TSH, but it does not usually cause the gland to grow.

Q: 17-OH progesterone level in congenital adrenal hyperplasia in 1 year old child (in ng/dL)-

>600. ***>600 ng/dL*** - In **classic congenital adrenal hyperplasia (CAH)** due to **21-hydroxylase deficiency**, a 17-OH progesterone level greater than 600 ng/dL is highly indicative, especially in a 1-year-old. - This significantly elevated level reflects the **blocked conversion** of 17-OH progesterone to 11-deoxycortisol in the adrenal steroid synthesis pathway. *<150 ng/dL* - This level is considered **normal** for 17-OH progesterone in a 1-year-old child and would rule out classic CAH. - Normal concentrations indicate an **intact 21-hydroxylase enzyme** pathway, allowing for proper cortisol synthesis. *150-300 ng/dL* - While not normal, this range might suggest **non-classic or attenuated CAH**, where the enzyme deficiency is partial, and the elevation is less pronounced than in classic forms. - For classic CAH in an infant or young child, a significantly higher elevation would be expected. *300-600 ng/dL* - This range is also **suggestive of CAH**, but in most cases of classic 21-hydroxylase deficiency in infancy, the 17-OH progesterone levels are considerably higher. - Levels within this range might be seen in less severe forms of the disorder or under specific testing conditions, but **>600 ng/dL** is more characteristic for classic CAH in this age group.

Q: Commonest cause of hypothyroidism is

Thyroid dysgenesis. **Thyroid dysgenesis** - **Thyroid dysgenesis** refers to congenital defects in thyroid gland development (e.g., aplasia, hypoplasia, ectopia) and is the most frequent cause worldwide of **congenital hypothyroidism** [1]. - Early detection and treatment with thyroid hormone replacement are crucial to prevent **intellectual disability** and developmental delays [1]. *Defect of iodide transport* - This is a rare genetic disorder affecting the **sodium-iodide symporter (NIS)**, leading to impaired iodide uptake by the thyroid gland. - While it causes hypothyroidism, it is significantly less common than thyroid dysgenesis. *Defective synthesis of thyroxine* - This refers to various inherited defects in the enzymes involved in thyroid hormone synthesis (e.g., peroxidase deficiency, organification defects). - These are collectively known as **dyshormonogenesis**, and although they cause congenital hypothyroidism, their incidence is lower than that of thyroid dysgenesis [1]. *Hashimoto's thyroiditis* - **Hashimoto's thyroiditis** is the most common cause of **acquired hypothyroidism** in adults, an autoimmune condition leading to thyroid gland destruction. - It is not the most common cause of hypothyroidism in general, especially when considering congenital forms.

Question 1

Precocious puberty in a girl is defined as breast development before the age of?

Accepted Answer

8 years

Answer

10 years

Answer

6 years

Answer

12 years

Question 2

Hypocalcemia in a child may be associated with

Accepted Answer

All of the options

Answer

DiGeorge syndrome

Answer

Magnesium deficiency

Answer

Hypoparathyroidism

Question 3

Following are the features of cretinism, except

Accepted Answer

Normal intelligence

Answer

Characteristic facial features

Answer

Pot-belly

Answer

Stunted growth

Question 4

Congenital adrenal hyperplasia is the most common cause of

Accepted Answer

Female pseudohermaphroditism (androgenized female 46XX)

Answer

True hermaphroditism

Answer

Male pseudohermaphroditism (underandrogenized male 46XY)

Answer

Turner's syndrome

Question 5

Treatment for childhood hypothyroidism is with -

Accepted Answer

Levothyroxine

Answer

TSH

Answer

Propylthiouracil

Answer

T3

Question 6

A five year old boy presents with precocious puberty and a Blood pressure of 130/80 mm Hg. Estimation of which of the following will help in diagnosis

Accepted Answer

17 hydroxy - progesterone

Answer

Cortisol

Answer

11-deoxycortisol

Answer

Aldosterone

Question 7

Association of sexual precocity, multiple cystic bone lesions and endocrinopathies are seen in:

Accepted Answer

McCune-Albright's syndrome

Answer

Hepatoblastoma

Answer

Androblastoma

Answer

Granulosa cell tumor

Question 8

A one-year-old child presents with short stature, lethargy, and constipation. Clinical examination shows a palpable goiter. Laboratory investigations revealed a low T4 and elevated TSH. Which of the following is the most likely diagnosis?

Accepted Answer

Thyroid Dyshormonogenesis

Answer

Central Hypothyroidism

Answer

Thyroid Dysgenesis

Answer

TSH Receptor Blocking Antibody

Question 9

17-OH progesterone level in congenital adrenal hyperplasia in 1 year old child (in ng/dL)-

Accepted Answer

>600

Answer

<150

Answer

150-300

Answer

300-600

Question 10

Commonest cause of hypothyroidism is

Accepted Answer

Thyroid dysgenesis

Answer

Defect of iodide transport

Answer

Defective synthesis of thyroxine

Answer

Hashimoto's thyroiditis

Endocrinology — MCQs

Endocrinology — MCQs

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