Endocrinology — MCQs

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 161: All of the following hormones can affect the growth of a child except?

A. Growth Hormone (GH)
B. Adrenocorticotropic Hormone (ACTH) (Correct Answer)
C. Insulin
D. All

Explanation: **Explanation:** The growth of a child is a complex process regulated by a specific interplay of hormones. The correct answer is **ACTH (Adrenocorticotropic Hormone)** because it does not have a direct stimulatory effect on linear growth. In fact, if ACTH is produced in excess (as seen in Cushing’s Disease), it leads to an overproduction of cortisol, which is **potent inhibitor** of growth, causing premature closure of epiphyses and growth failure. **Analysis of Options:** * **Growth Hormone (GH):** This is the primary regulator of postnatal growth. It acts directly on tissues and indirectly by stimulating the liver to produce **IGF-1** (Insulin-like Growth Factor 1), which promotes chondrocyte proliferation at the epiphyseal plate. * **Insulin:** Insulin is a critical growth promoter, particularly during the **fetal period**. It has structural similarities to IGF-1 and promotes protein synthesis and cell division. Children with hyperinsulinism (e.g., infants of diabetic mothers) often show macrosomia (excessive growth). * **Thyroid Hormones (T3/T4):** (Though not an option, they are vital) They are essential for bone maturation and allow GH to exert its full effect. **NEET-PG High-Yield Pearls:** 1. **Fetal Growth:** Primarily regulated by **Insulin and IGF-2**. Growth Hormone (GH) plays a minimal role in utero. 2. **Postnatal Growth:** Primarily regulated by **GH, IGF-1, and Thyroid hormones**. 3. **Pubertal Growth Spurt:** Driven by the synergistic action of **GH and Sex Steroids** (Estrogen/Testosterone). 4. **Glucocorticoids:** While necessary for life, an excess of glucocorticoids (via ACTH) is always **growth-suppressive**.

Question 162: Which medication is used in the treatment of idiopathic central precocious puberty?

A. Exogenous gonadotrophins
B. Ethinyl estradiol
C. GnRH analogues (Correct Answer)
D. Ethinyl estradiol

Explanation: **Explanation:** **Central Precocious Puberty (CPP)** is caused by the premature activation of the hypothalamic-pituitary-gonadal (HPG) axis, leading to early secretion of GnRH, which stimulates the pituitary to release LH and FSH. **Why GnRH Analogues are the Correct Answer:** The gold standard treatment for idiopathic CPP is the administration of **long-acting GnRH analogues** (e.g., Leuprolide, Goserelin). While physiological GnRH is released in a pulsatile manner to stimulate the pituitary, continuous administration of a potent GnRH analogue leads to the **downregulation and desensitization** of GnRH receptors on the pituitary gonadotrophs. This results in the suppression of LH and FSH secretion, effectively "pausing" pubertal progression and preventing premature epiphyseal fusion. **Why Other Options are Incorrect:** * **Exogenous Gonadotrophins:** These (LH/FSH) would further stimulate the gonads to produce sex steroids, worsening the precocity. * **Ethinyl Estradiol:** This is an estrogen. Administering it would accelerate bone age maturation and secondary sexual characteristics, which is the opposite of the treatment goal. **High-Yield Clinical Pearls for NEET-PG:** * **Definition:** Development of secondary sexual characteristics before **8 years** in girls and **9 years** in boys. * **Primary Goal of Therapy:** To preserve **final adult height** by preventing early closure of epiphyseal plates. * **Diagnosis:** The "Gold Standard" test is the **GnRH Stimulation Test** (a pubertal response shows a peak LH > 5-8 IU/L). * **Bone Age:** In CPP, bone age is typically advanced compared to chronological age. * **Monitoring:** Treatment is usually continued until the child reaches an age appropriate for normal puberty.

Question 163: What is the most common cause of thyrotoxicosis in childhood?

A. Toxic nodular goiter
B. Toxic adenoma
C. Graves disease (Correct Answer)
D. Thyrotoxicosis factitia

Explanation: **Explanation:** **Graves Disease (Option C)** is the most common cause of thyrotoxicosis in children and adolescents, accounting for over **90-95% of pediatric cases**. It is an autoimmune disorder caused by **Thyroid Stimulating Immunoglobulins (TSI)** that bind to and activate the TSH receptor, leading to excessive thyroid hormone production and thyroid hyperplasia. It is most frequently seen in adolescent girls, with a peak incidence between 11 and 15 years of age. **Why other options are incorrect:** * **Toxic nodular goiter (Option A) and Toxic adenoma (Option B):** These are common causes of hyperthyroidism in the elderly but are exceedingly rare in the pediatric population. They involve autonomous functioning nodules (Plummer disease) rather than a diffuse autoimmune process. * **Thyrotoxicosis factitia (Option D):** This refers to the intentional or accidental ingestion of exogenous thyroid hormone. While it must be considered in the differential diagnosis of suppressed TSH with low thyroglobulin levels, it is not a common cause in children. **High-Yield Clinical Pearls for NEET-PG:** * **Triad of Graves:** Hyperthyroidism, Diffuse Goiter, and Exophthalmos (though ophthalmopathy is often milder in children than in adults). * **Clinical Presentation:** Look for accelerated linear growth, advanced bone age, emotional lability, and declining school performance. * **Diagnosis:** Suppressed TSH, elevated Free T4/T3, and **diffuse** increased uptake on Radionuclide (Technetium-99m) scan. * **Treatment:** **Methimazole** is the first-line medical therapy. Propylthiouracil (PTU) is generally avoided in children due to the risk of severe hepatotoxicity.

Question 164: A 6-year-old girl presents with precocious puberty, bony lesions, and hyperpigmented skin lesions. What is the most probable diagnosis?

A. Prader Willi syndrome
B. Laurence Moon syndrome
C. Cushing syndrome
D. McCune-Albright syndrome (Correct Answer)

Explanation: **Explanation:** The clinical triad of **precocious puberty, polyostotic fibrous dysplasia (bony lesions), and café-au-lait skin spots** is the hallmark of **McCune-Albright Syndrome (MAS)**. **1. Why the Correct Answer is Right:** MAS is caused by a somatic (post-zygotic) mutation in the **GNAS gene**, which encodes the alpha subunit of the **Gs stimulatory protein**. This leads to constitutive activation of adenylate cyclase, causing overproduction of cAMP. This "always-on" signaling mimics the effects of various hormones, leading to: * **Endocrinopathies:** Most commonly **GnRH-independent (peripheral) precocious puberty** (recurrent ovarian cysts and vaginal bleeding in girls). * **Bone Lesions:** Polyostotic fibrous dysplasia (replacement of bone with fibrous tissue), often leading to fractures. * **Skin Lesions:** Large, irregular café-au-lait spots, typically described as having **"Coast of Maine"** borders (jagged), unlike the smooth "Coast of California" borders seen in Neurofibromatosis Type 1. **2. Why Other Options are Incorrect:** * **Prader-Willi Syndrome:** Characterized by hypotonia, hyperphagia leading to obesity, and **hypogonadotropic hypogonadism** (delayed puberty), not precocious puberty. * **Laurence-Moon Syndrome:** A rare ciliopathy featuring retinitis pigmentosa, intellectual disability, and hypogonadism. * **Cushing Syndrome:** Presents with weight gain, moon facies, and growth retardation. While it involves hormonal excess (cortisol), it does not present with fibrous dysplasia or the classic triad of MAS. **Clinical Pearls for NEET-PG:** * **Inheritance:** It is **not inherited**; it occurs due to a mosaic somatic mutation. If the mutation were germline, it would be lethal. * **Skin Findings:** Café-au-lait spots in MAS usually respect the midline. * **Other Associations:** Can include hyperthyroidism, GH-secreting pituitary adenomas, and adrenal hyperplasia.

Question 165: Which of the following statements is FALSE about McCune-Albright syndrome?

A. It is an inherited disorder. (Correct Answer)
B. It is associated with bone abnormalities.
C. It is characterized by café au lait spots.
D. It can present with precocious puberty.

Explanation: **Explanation:** McCune-Albright Syndrome (MAS) is defined by a classic triad of **polyostotic fibrous dysplasia**, **café au lait spots**, and **hyperfunctioning endocrinopathies** (most commonly gonadotropin-independent precocious puberty). **Why Option A is the correct (False) statement:** McCune-Albright syndrome is **not an inherited disorder**. It is caused by a **sporadic, post-zygotic somatic mutation** in the *GNAS1* gene, which encodes the alpha subunit of the Gs stimulatory protein. Because the mutation occurs after fertilization, it results in **mosaicism** (a mix of normal and mutated cells). If the mutation were germline (inherited), it would be lethal to the developing embryo. **Why the other options are true:** * **Option B:** Bone abnormalities are a hallmark, specifically **polyostotic fibrous dysplasia**, where normal bone is replaced by fibrous tissue, leading to fractures and deformities (e.g., "Shepherd’s crook" deformity). * **Option C:** **Café au lait spots** in MAS are typically large, unilateral, and have irregular borders described as the **"Coast of Maine"** appearance (unlike the smooth "Coast of California" spots in Neurofibromatosis type 1). * **Option D:** **Precocious puberty** in MAS is **peripheral (GnRH-independent)**, caused by autonomous overactivity of the ovaries or testes. **High-Yield Clinical Pearls for NEET-PG:** * **Mutation:** Somatic mutation in *GNAS* gene → Constitutive activation of Adenylate Cyclase → Increased cAMP. * **Endocrinopathies:** Besides precocious puberty, patients may have hyperthyroidism, GH-secreting pituitary adenomas (acromegaly), or Cushing syndrome. * **Radiology:** Fibrous dysplasia shows a characteristic **"Ground-glass appearance"** on X-ray.

Question 166: The features of neonatal hypothyroidism include all EXCEPT:

A. Triangular facies with craniosynostosis (Correct Answer)
B. Congestive cardiac failure
C. Delayed osseous maturation
D. Goitre is rare

Explanation: **Explanation:** The correct answer is **A (Triangular facies with craniosynostosis)** because these features are characteristic of **Antley-Bixler syndrome** or certain craniosynostosis syndromes, not neonatal hypothyroidism. In contrast, neonatal hypothyroidism is associated with a **large anterior fontanelle** and delayed closure of sutures, rather than premature fusion (craniosynostosis). **Analysis of Options:** * **Congestive Cardiac Failure (B):** While rare, severe untreated hypothyroidism can lead to myxedematous cardiomyopathy, bradycardia, and pericardial effusion, which may progress to high-output heart failure or circulatory collapse. * **Delayed Osseous Maturation (C):** This is a hallmark feature. Thyroid hormones are essential for bone mineralization. Radiographs often show the **absence of distal femoral epiphysis** (normally present at 36 weeks gestation), serving as a marker for intrauterine hypothyroidism. * **Goitre is Rare (D):** In the majority of cases (85%), neonatal hypothyroidism is caused by **thyroid dysgenesis** (aplasia, hypoplasia, or ectopic gland), where no goitre is present. Goitrous hypothyroidism is typically seen only in rarer dyshormonogenesis cases. **Clinical Pearls for NEET-PG:** * **Most common cause:** Thyroid dysgenesis (Ectopic gland is the most common specific type). * **Early signs:** Prolonged physiological jaundice, poor feeding, lethargy, and a "hoarse cry." * **Physical findings:** Umbilical hernia, macroglossia, and a large posterior fontanelle (>0.5 cm). * **Screening:** Best done between **48–72 hours** of life to avoid the physiological TSH surge. * **Treatment:** Levothyroxine (10–15 μg/kg/day) is the gold standard to prevent permanent intellectual disability.

Question 167: What is the best prenatal treatment for congenital adrenal hyperplasia (CAH)?

A. Dexamethasone (Correct Answer)
B. Betamethasone
C. Prednisolone
D. Hydrocortisone

Explanation: **Explanation:** The primary goal of prenatal treatment in Congenital Adrenal Hyperplasia (CAH), specifically the 21-hydroxylase deficiency variant, is to **prevent the virilization of a female fetus**. This is achieved by suppressing the fetal pituitary-adrenal axis, thereby reducing the production of adrenal androgens. **Why Dexamethasone is the Correct Answer:** Dexamethasone is the drug of choice because it is **not inactivated by the placental enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2)**. Unlike most other steroids, dexamethasone crosses the placenta in its active form, reaching the fetal circulation effectively to suppress fetal ACTH secretion. Treatment must be initiated early (before the 9th week of gestation) to be effective. **Why Other Options are Incorrect:** * **B. Betamethasone:** While it also crosses the placenta, Dexamethasone is the standard established protocol in clinical guidelines for CAH virilization prevention. * **C. Prednisolone & D. Hydrocortisone:** These are **extensively metabolized/inactivated** by the placental 11β-HSD2 enzyme into inactive forms (prednisone and cortisone, respectively). Consequently, they do not reach the fetus in sufficient concentrations to suppress the adrenal axis. **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** Treatment must start as soon as pregnancy is confirmed (ideally by **6–7 weeks**) and before the onset of external genitalia differentiation (9 weeks). * **Indication:** Treatment is only indicated if the fetus is **female**. If genetic testing (CVS or NIPT) reveals a male fetus, treatment is discontinued. * **Side Effects:** Long-term prenatal dexamethasone is controversial due to potential maternal side effects (weight gain, striae) and concerns regarding the child's long-term cognitive development. * **Diagnosis:** The gold standard for postnatal diagnosis of 21-hydroxylase deficiency is an elevated **17-hydroxyprogesterone (17-OHP)** level.

Question 168: Which of the following statements about Hashimoto's thyroiditis in children is FALSE?

A. Hashimoto's thyroiditis is uncommon in children.
B. Surgery is the treatment of choice. (Correct Answer)
C. Genetic disorders are risk factors for developing Hashimoto's thyroiditis in children.
D. Signs of hypothyroidism are seen.

Explanation: **Explanation:** **Hashimoto’s Thyroiditis (Chronic Lymphocytic Thyroiditis)** is the most common cause of acquired hypothyroidism in children and adolescents. 1. **Why Option B is False (Correct Answer):** Surgery is **not** the treatment of choice for Hashimoto’s thyroiditis. The management is primarily medical. If the patient is hypothyroid, the treatment of choice is **Levothyroxine (L-T4) replacement therapy**. Surgery is only indicated in rare circumstances, such as a very large goiter causing compressive symptoms (dysphagia or stridor) or suspicion of malignancy (e.g., papillary thyroid carcinoma). 2. **Analysis of Other Options:** * **Option A:** While it is the most common cause of goitrous hypothyroidism, it is relatively **uncommon in very young children** (infants and toddlers). The incidence peaks during adolescence, making it "uncommon" in the general pediatric population compared to adults. * **Option C:** There is a strong association with genetic disorders. Children with **Down syndrome, Turner syndrome, and Klinefelter syndrome** have a significantly higher risk of developing autoimmune thyroiditis. * **Option D:** Clinical features often include signs of hypothyroidism such as growth retardation, delayed bone age, cold intolerance, constipation, and a firm, non-tender goiter. **High-Yield Clinical Pearls for NEET-PG:** * **Antibodies:** Anti-thyroid peroxidase (Anti-TPO) and Anti-thyroglobulin (Anti-Tg) are the hallmark markers. * **Histology:** Characterized by lymphocytic infiltration and **Hurthle cells** (Askanazy cells). * **Hashitoxicosis:** A transient hyperthyroid phase may occur early in the disease due to the release of preformed thyroid hormones from follicular destruction. * **Association:** Often associated with other autoimmune conditions like Type 1 Diabetes and Celiac disease (APS Type 2).

Question 169: An infant presents with absence of a social smile, no eyebrows, and a protruded tongue. What is the most likely diagnosis?

A. Cretinism (Correct Answer)
B. Down's syndrome
C. Mucopolysaccharidosis
D. Rickets

Explanation: **Explanation:** The clinical presentation of an infant with a **protruded tongue**, **absence of a social smile** (indicating developmental/mental delay), and **absence of eyebrows** (specifically the lateral third, known as Hertoghe's sign) is classic for **Cretinism** (Congenital Hypothyroidism). **1. Why Cretinism is Correct:** Congenital hypothyroidism leads to a generalized slowing of metabolic and developmental processes. The protruded tongue (macroglossia) occurs due to the accumulation of glycosaminoglycans. The absence of a social smile reflects the neurodevelopmental delay characteristic of untreated hypothyroidism. Thinning or absence of eyebrows is a specific dermatological sign of low thyroid hormone levels. **2. Why Other Options are Incorrect:** * **Down’s Syndrome:** While it presents with a protruded tongue and developmental delay, it is typically associated with specific dysmorphic features like up-slanting palpebral fissures, epicanthic folds, and a flat nasal bridge, rather than the loss of eyebrows. * **Mucopolysaccharidosis (e.g., Hurler Syndrome):** These patients have macroglossia and developmental delay, but they typically present with "coarse" facial features, hepatosplenomegaly, and corneal clouding, which are absent here. * **Rickets:** This is a disorder of bone mineralization. Key findings include craniotabes, rachitic rosary, and wide epiphyses, not macroglossia or loss of eyebrows. **Clinical Pearls for NEET-PG:** * **Most common cause:** Thyroid dysgenesis (Ectopic thyroid is the most common specific type). * **Earliest Sign:** Prolonged physiological jaundice. * **Other signs:** Hoarse cry, umbilical hernia, large posterior fontanelle, and constipation. * **Screening:** Best done via heel-prick test for TSH between 48–72 hours of birth.

Question 170: What is the best prenatal treatment for Congenital Adrenal Hyperplasia (CAH)?

A. Dexamethasone (Correct Answer)
B. Betamethasone
C. Prednisolone
D. Hydrocortisone

Explanation: **Explanation:** The primary goal of prenatal treatment in Congenital Adrenal Hyperplasia (CAH) is to prevent the **virilization of a female fetus** by suppressing the fetal pituitary-adrenal axis, thereby reducing the production of adrenal androgens. **1. Why Dexamethasone is the Correct Answer:** Dexamethasone is the drug of choice because it is **not inactivated by the placental enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2)**. Unlike most other steroids, dexamethasone crosses the placenta in its active form, reaching the fetal circulation effectively to suppress fetal ACTH secretion. Treatment must be started early (before the 9th week of gestation) to be effective. **2. Why Other Options are Incorrect:** * **Betamethasone:** While it also crosses the placenta (used for fetal lung maturity), Dexamethasone is the standard established protocol for CAH due to more extensive clinical data regarding its efficacy in androgen suppression. * **Prednisolone & Hydrocortisone:** These are the preferred treatments for the **mother** or for **postnatal** CAH. However, they are poor choices for prenatal fetal treatment because they are extensively metabolized/inactivated by the placental 11β-HSD2 enzyme, failing to reach the fetus in therapeutic concentrations. **Clinical Pearls for NEET-PG:** * **Timing:** Treatment must begin as soon as pregnancy is confirmed (ideally by 6 weeks) and before the 9th week, as genital ambiguity begins at 7–8 weeks. * **Indication:** Treatment is only indicated if the fetus is **female** and affected. Since the sex/genotype is often unknown at 6 weeks, many male or unaffected female fetuses are treated unnecessarily until CVS or amniocentesis confirms the status. * **Dose:** Standard dose is 20 μg/kg/day in three divided doses.

Practice by Chapter

Disorders of Growth

Practice Questions

Thyroid Disorders

Practice Questions

Disorders of Puberty

Practice Questions

Adrenal Disorders

Practice Questions

Diabetes Mellitus in Children

Practice Questions

Disorders of Calcium and Phosphate Metabolism

Practice Questions

Disorders of Sexual Development

Practice Questions

Hypoglycemia

Practice Questions

Obesity and Metabolic Syndrome

Practice Questions

Pituitary Disorders

Practice Questions

Multiple Endocrine Neoplasia Syndromes

Practice Questions

Endocrine Emergencies

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free