Endocrinology Practice Questions

Q: What is the commonest feature of hypothyroidism in children?

Cold extremities. **Explanation:** Hypothyroidism, whether congenital or acquired, leads to a generalized slowing of metabolic processes. Thyroid hormones are essential for thermogenesis and maintaining the basal metabolic rate (BMR). **1. Why "Cold Extremities" is correct:** In hypothyroidism, the reduction in metabolic heat production leads to peripheral vasoconstriction as the body attempts to conserve core temperature. This results in **cold extremities** and **cold intolerance**, which are among the most common and earliest clinical signs. Other frequent features include lethargy, constipation, bradycardia, and dry skin. **2. Why the other options are incorrect:** * **A. Cataract:** This is not a feature of hypothyroidism. However, it is a classic finding in **Hypoparathyroidism** (due to chronic hypocalcemia) and **Galactosemia**. * **B. Recurrent Seizures:** While severe hypothyroidism (Myxedema coma) can cause mental status changes, recurrent seizures are not a standard feature. Seizures are more characteristic of **Hypocalcemia** (often seen in hypoparathyroidism) or hypoglycemia. * **D. Laryngospasms:** This is a specific sign of neuromuscular irritability caused by **Hypocalcemia** (Tetany), not hypothyroidism. **Clinical Pearls for NEET-PG:** * **Most common cause of Congenital Hypothyroidism:** Thyroid dysgenesis (Ectopy is the most common specific type). * **Most common cause of Acquired Hypothyroidism:** Hashimoto’s thyroiditis. * **Early Sign in Neonates:** Prolonged physiological jaundice and a large posterior fontanelle (>0.5 cm). * **Key Growth Finding:** The most sensitive clinical indicator of hypothyroidism in children is a **decrease in growth velocity** leading to short stature with delayed bone age.

Q: A newborn baby presents with shock, hyperkalemia, and hypoglycemia. What is the most likely diagnosis?

Congenital adrenal hyperplasia. **Explanation:** The clinical triad of **shock, hyperkalemia, and hypoglycemia** in a newborn is a classic presentation of an **Adrenal Crisis**, most commonly caused by **Congenital Adrenal Hyperplasia (CAH)**. **Why CAH is the correct answer:** The most common form of CAH is **21-hydroxylase deficiency**. This enzyme defect leads to: 1. **Mineralocorticoid deficiency (Aldosterone):** Causes "salt-wasting," resulting in hyponatremia, **hyperkalemia**, and dehydration leading to hypovolemic **shock**. 2. **Glucocorticoid deficiency (Cortisol):** Leads to impaired gluconeogenesis, resulting in **hypoglycemia** and poor stress response. 3. **Androgen excess:** May cause ambiguous genitalia in females (though males may appear normal initially). **Why other options are incorrect:** * **Septicemia:** While it causes shock and hypoglycemia, it typically presents with a normal or low potassium level (unless complicated by acute renal failure). * **Inborn Error of Metabolism (IEM):** Many IEMs cause hypoglycemia and metabolic acidosis, but they rarely present with the specific electrolyte pattern of hyperkalemia and hyponatremia seen in adrenal insufficiency. * **Diabetes Mellitus:** Neonatal diabetes presents with hyperglycemia and dehydration, not hypoglycemia. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Elevated levels of **17-hydroxyprogesterone (17-OHP)**. * **Electrolyte Hallmark:** Hyponatremia + Hyperkalemia + Metabolic Acidosis. * **Immediate Management:** Aggressive fluid resuscitation (Normal Saline) and IV Hydrocortisone. * **Karyotyping:** Essential in female infants with ambiguous genitalia to confirm 46,XX.

Q: An 8-year-old girl presents with symptoms of rickets. Laboratory investigations reveal Serum Calcium 7.2 mg/dL, Serum Phosphates 2.3 mg/dL, and Alkaline Phosphatase 2420 IU/L. What is the most probable diagnosis?

Nutritional rickets. ### Explanation **Correct Answer: C. Nutritional rickets** The clinical and biochemical profile points towards **Nutritional Vitamin D Deficiency Rickets**. In this condition, the primary pathology is a deficiency of Vitamin D, leading to decreased intestinal absorption of calcium and phosphorus. 1. **Low Serum Calcium (7.2 mg/dL):** This is the hallmark of nutritional rickets. Low calcium triggers a compensatory rise in Parathyroid Hormone (Secondary Hyperparathyroidism). 2. **Low Serum Phosphate (2.3 mg/dL):** Elevated PTH causes phosphaturia (renal loss of phosphate), leading to hypophosphatemia. 3. **Markedly Elevated Alkaline Phosphatase (2420 IU/L):** This reflects increased osteoblastic activity and is a sensitive marker for the severity and activity of rickets. --- ### Why other options are incorrect: * **Hypophosphatemic Rickets (X-linked):** The primary defect is renal phosphate wasting. Characteristically, **Serum Calcium is normal**, while phosphate is low. * **Vitamin D-dependent rickets (VDDR) Type II:** While biochemical markers are similar (low Ca, low PO4), this is a rare genetic resistance to Vitamin D. It is usually associated with **alopecia**, which is not mentioned here. * **Secondary Hyperparathyroidism:** This is a *physiological response* to low calcium (seen in nutritional rickets or CKD), not a primary diagnosis for rickets in this context. --- ### High-Yield Clinical Pearls for NEET-PG: * **Earliest Radiological Sign:** Cupping and splaying of the metaphysis (best seen at the distal radius/ulna). * **Earliest Biochemical Change:** Decreased Serum Phosphorus (due to early PTH rise). * **Most Sensitive Marker of Healing:** Falling levels of Alkaline Phosphatase. * **Vitamin D Levels:** In nutritional rickets, 25(OH)D levels are low, whereas in VDDR Type II, 1,25(OH)₂D levels are actually elevated due to receptor resistance.

Q: A 9-year-old girl presents for evaluation of regular vaginal bleeding. History reveals thelarche at 7 years and adrenarche at 8 years. What is the most common cause of this condition in girls?

Idiopathic. This clinical scenario describes **Central Precocious Puberty (CPP)**, defined as the development of secondary sexual characteristics before age 8 in girls. The sequence of events (thelarche → adrenarche → menarche) follows the normal physiological pattern but occurs prematurely due to early activation of the Hypothalamic-Pituitary-Gonadal (HPG) axis. ### **Explanation of Options** * **A. Idiopathic (Correct):** In approximately **80–90% of girls** with CPP, no identifiable organic cause is found. This is termed "Idiopathic CPP." It is a diagnosis of exclusion and is significantly more common in females than in males (where organic causes like CNS tumors are more prevalent). * **B. Gonadal Tumors:** These (e.g., Granulosa cell tumors) cause **Peripheral Precocious Puberty**. In these cases, the HPG axis is suppressed (low FSH/LH), and the sequence of puberty is often deranged. * **C. McCune-Albright Syndrome:** This is a form of peripheral precocity characterized by the triad of polyostotic fibrous dysplasia, café-au-lait spots, and autonomous endocrine overactivity. It is a rare genetic cause, not the most common. * **D. Hypothyroidism:** Severe primary hypothyroidism can cause "Van Wyk-Grumbach Syndrome," leading to precocious puberty due to high TSH levels cross-reacting with FSH receptors. This is a rare, reversible cause. ### **NEET-PG High-Yield Pearls** * **Gold Standard Investigation:** GnRH Stimulation Test. In CPP, there is a **pubertal response** (LH rise >5–10 IU/L). * **Bone Age:** Typically advanced in all forms of true precocious puberty, leading to premature epiphyseal closure and short adult stature. * **Treatment of Choice:** Long-acting **GnRH agonists** (e.g., Leuprolide) to desensitize the pituitary and halt progression. * **Gender Rule:** Precocious puberty in girls is usually **Idiopathic**; in boys, it is usually **Organic** (CNS lesions).

Q: An 8-day-old male infant presents with vomiting, lethargy, dehydration, and features of shock. Clinical examination reveals hyperpigmentation of the genital skin and normal external genitalia. Blood tests reveal sodium of 124 mEq/L, potassium of 7 mEq/L, and hypoglycemia. What is the most likely diagnosis?

Congenital Adrenal Hyperplasia (CAH). ### Explanation The clinical presentation is classic for **Congenital Adrenal Hyperplasia (CAH)**, specifically the **salt-wasting form of 21-hydroxylase deficiency**. **1. Why CAH is the Correct Answer:** * **Pathophysiology:** A deficiency in 21-hydroxylase leads to impaired synthesis of cortisol and aldosterone. * **Salt-Wasting Crisis:** Low aldosterone causes sodium loss (hyponatremia) and potassium retention (hyperkalemia), leading to dehydration, vomiting, and shock. Low cortisol leads to hypoglycemia. * **Hyperpigmentation:** Low cortisol triggers a feedback increase in ACTH. Since ACTH and Melanocyte-Stimulating Hormone (MSH) share a common precursor (POMC), excess ACTH causes hyperpigmentation (noted here on the genitals). * **Genitalia:** In males, external genitalia appear normal because excess androgens do not cause malformations in males (unlike females, who present with ambiguous genitalia/virilization). **2. Why Other Options are Incorrect:** * **Adrenal Hemorrhage:** While it can cause adrenal insufficiency, it is usually associated with birth trauma, sepsis, or a palpable abdominal mass. It would not explain the generalized hyperpigmentation seen from birth. * **Acute Gastroenteritis:** While it causes vomiting and dehydration, it typically presents with *hypernatremia* or *isonatremia* and *hypokalemia*. It does not cause hyperpigmentation or hypoglycemia. * **Hyperaldosteronism:** This would cause the exact opposite electrolyte profile: hypernatremia and hypokalemia. **3. NEET-PG High-Yield Pearls:** * **Most common cause of CAH:** 21-hydroxylase deficiency (90-95%). * **Diagnostic Marker:** Elevated **17-hydroxyprogesterone (17-OHP)**. * **Karyotype:** In a female with CAH, the karyotype is 46,XX, but she presents with ambiguous genitalia (Prader staging). * **Management:** Immediate fluid resuscitation (Normal Saline) and IV Hydrocortisone.

Q: In Prader-Willi syndrome, which of the following is increased?

Ghrelin. **Explanation:** **Prader-Willi Syndrome (PWS)** is a complex genetic disorder caused by the loss of function of genes on the paternal chromosome **15q11-q13**. The hallmark of the syndrome is severe hyperphagia (uncontrollable hunger) leading to morbid obesity. **Why Ghrelin is Increased:** Ghrelin is an "orexigenic" (appetite-stimulating) hormone produced primarily by the P/D1 cells of the stomach. In PWS, there is a characteristic **elevation of circulating Ghrelin levels** (hyperghrelinemia) even before the onset of obesity [1]. This elevation is thought to be a primary driver of the persistent hunger and lack of satiety seen in these patients. Unlike simple obesity where ghrelin is usually suppressed, in PWS, it remains high, making it a high-yield diagnostic marker. **Why Other Options are Incorrect:** * **LH & FSH (Options A & B):** PWS is associated with **Hypogonadotropic Hypogonadism** due to hypothalamic dysfunction. Therefore, levels of Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) are typically **decreased**, leading to genital hypoplasia and delayed puberty. * **TSH (Option C):** Central hypothyroidism can occur in PWS due to hypothalamic-pituitary axis dysfunction, meaning **TSH** levels are usually **low or inappropriately normal**, but not increased. **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** Paternal deletion of 15q11-q13 (most common) or Maternal Uniparental Disomy (UPD). * **Infancy:** Characterized by severe **hypotonia** ("floppy baby") and feeding difficulties. * **Childhood:** Transition to hyperphagia, obesity, short stature, and small hands/feet. * **Key Association:** High Ghrelin + Low GnRH (leading to low LH/FSH).

Q: A nineteen-year-old female with short stature, wide-spaced nipples, and primary amenorrhea most likely has which karyotype?

45, XO. ### Explanation The clinical presentation of **short stature, wide-spaced nipples (shield chest), and primary amenorrhea** in a female is the classic triad for **Turner Syndrome**. **1. Why 45, XO is correct:** Turner Syndrome is the most common sex chromosome abnormality in females, characterized by the complete or partial absence of one X chromosome. The lack of the second X chromosome leads to **gonadal dysgenesis** (streak ovaries), resulting in low estrogen levels, elevated gonadotropins (hypergonadotropic hypogonadism), and subsequent primary amenorrhea. Short stature is attributed to the loss of the **SHOX gene** located on the distal limb of the X chromosome. **2. Why the other options are incorrect:** * **47, XX + 18 (Edwards Syndrome):** This is an autosomal trisomy characterized by severe intellectual disability, micrognathia, low-set ears, and clenched fists with overlapping fingers. It is usually fatal within the first year of life. * **46, XXXY:** This is a rare variant of Klinefelter syndrome. While it presents with tall stature and hypogonadism, it occurs in **males**, not females. * **47, XXY (Klinefelter Syndrome):** This is the most common sex chromosome aneuploidy in **males**. It presents with tall stature, gynecomastia, small firm testes, and infertility, which does not match the female phenotype described. **3. Clinical Pearls for NEET-PG:** * **Most common cardiac defect:** Bicuspid aortic valve (most frequent); Coarctation of the aorta (highly specific). * **Renal anomaly:** Horseshoe kidney. * **Dermatological finding:** Lymphedema of hands and feet (at birth) and multiple pigmented nevi. * **Intelligence:** Usually normal, but may have difficulties with visuospatial organization. * **Karyotype variety:** 50% are 45,XO; others may be mosaics (e.g., 45,XO/46,XX) or have structural abnormalities of the X chromosome.

Q: A 10-year-old child weighs 40 kg and presents with mental retardation. On examination, the upper segment to lower segment (US:LS) ratio is 1.1:1. What is the most likely diagnosis?

Cretinism. ***Cretinism*** - **Cretinism** (untreated congenital **hypothyroidism**) is the classic cause of the combination of **mental retardation** and **short stature with increased US:LS ratio** in children. - **Mental retardation** is a hallmark feature of cretinism due to the critical role of thyroid hormone in brain development during fetal and early postnatal life. - The **increased US:LS ratio** (1.1:1 at age 10, compared to normal 1.0:1) results from **disproportionate skeletal growth** with delayed bone maturation and relatively shorter lower limbs. - Clinical features include coarse facial features, large tongue, umbilical hernia, prolonged jaundice, hypotonia, and delayed developmental milestones. *Incorrect: Rickets* - **Rickets** (vitamin D deficiency) causes skeletal deformities including bowing of legs, rachitic rosary, and growth retardation with possible increased US:LS ratio. - However, **rickets does NOT cause mental retardation** — it is purely a disorder of bone mineralization and does not affect cognitive development. - The presence of mental retardation in this case rules out rickets as the primary diagnosis. *Incorrect: Achondroplasia* - Achondroplasia causes **rhizomelic dwarfism** with markedly increased US:LS ratio (typically >1.5:1), far more dramatic than the 1.1:1 seen here. - Crucially, **intelligence is normal** in achondroplasia, which contradicts the finding of mental retardation in this case. *Incorrect: Hypothyroidism* - **Acquired juvenile hypothyroidism** (after age 2-3 years) can cause growth failure and mild increase in US:LS ratio. - However, **severe mental retardation is rare** in acquired hypothyroidism because brain development is largely complete by this age. - The term "hypothyroidism" without qualifier typically refers to acquired disease, whereas **cretinism** specifically denotes congenital hypothyroidism with its characteristic neurological sequelae.

Q: What condition is likely in a newborn presenting with dry, rough skin, a big tongue and rough hair?

Congenital hypothyroidism. ***Congenital hypothyroidism*** - This condition is classically associated with signs of **cretinism** in newborns, including developmental delays, **dry/rough skin** (due to **myxedema**), and distinct facial features like **macroglossia** (big tongue). - The presentation of rough hair and generalized skin changes reflect reduced metabolic rate and accumulation of **glycosaminoglycans** in the dermis. *Prader-Willi syndrome* - Characterized by severe **neonatal hypotonia** and feeding difficulties followed by unremitting **hyperphagia** and obesity starting in early childhood. - The key features are related to the deletion of paternal chromosome 15 genes, and it does not typically present with the specific severe **myxedematous skin changes** seen here. *Edward syndrome* - Edward syndrome (**Trisomy 18**) is characterized by severe growth deficiency, **micrognathia**, **rocker-bottom feet**, overlapping fingers, and often severe congenital heart anomalies. - These findings are indicative of severe chromosomal abnormalities that typically result in distinct physical malformations, not primary hypothyroidism features such as **macroglossia** and widespread myxedema. *Galactosemia* - This is an inborn error of metabolism that usually presents after milk feeding starts, leading to poor feeding, **jaundice**, **hepatomegaly**, and subsequent formation of **cataracts**. - The initial clinical picture is dominated by metabolic decompensation, **sepsis (E. coli)**, and liver disease, not the classic physical features of thyroid hormone deficiency.

Question 1

What is the commonest feature of hypothyroidism in children?

Accepted Answer

Cold extremities

Answer

Cataract

Answer

Recurrent seizures

Answer

Laryngospasms

Question 2

A newborn baby presents with shock, hyperkalemia, and hypoglycemia. What is the most likely diagnosis?

Accepted Answer

Congenital adrenal hyperplasia

Answer

Septicemia

Answer

Inborn error of metabolism

Answer

Diabetes mellitus

Question 3

An 8-year-old girl presents with symptoms of rickets. Laboratory investigations reveal Serum Calcium 7.2 mg/dL, Serum Phosphates 2.3 mg/dL, and Alkaline Phosphatase 2420 IU/L. What is the most probable diagnosis?

Accepted Answer

Nutritional rickets

Answer

Vitamin D-dependent rickets type II

Answer

Hypophosphatemic rickets

Answer

Secondary hyperparathyroidism

Question 4

A 9-year-old girl presents for evaluation of regular vaginal bleeding. History reveals thelarche at 7 years and adrenarche at 8 years. What is the most common cause of this condition in girls?

Accepted Answer

Idiopathic

Answer

Gonadal tumors

Answer

McCune-Albright syndrome

Answer

Hypothyroidism

Question 5

An 8-day-old male infant presents with vomiting, lethargy, dehydration, and features of shock. Clinical examination reveals hyperpigmentation of the genital skin and normal external genitalia. Blood tests reveal sodium of 124 mEq/L, potassium of 7 mEq/L, and hypoglycemia. What is the most likely diagnosis?

Accepted Answer

Congenital Adrenal Hyperplasia (CAH)

Answer

Adrenal Haemorrhage

Answer

Acute Gastroenteritis with dehydration

Answer

Hyperaldosteronism

Question 6

In Prader-Willi syndrome, which of the following is increased?

Accepted Answer

Ghrelin

Answer

LH

Answer

FSH

Answer

TSH

Question 7

A nineteen-year-old female with short stature, wide-spaced nipples, and primary amenorrhea most likely has which karyotype?

Accepted Answer

45, XO

Answer

47, XX + 18

Answer

46XXXY

Answer

47, XXY

Question 8

In children with classical galactosemia, all the following are true except:

Accepted Answer

Elimination of galactose in the diet will not reverse cataract

Answer

E. coli neonatal sepsis is common

Answer

Galactose converts to galactitol, which is toxic to the brain

Answer

Children with the Duae variant of galactosemia are asymptomatic

Question 9

A 10-year-old child weighs 40 kg and presents with mental retardation. On examination, the upper segment to lower segment (US:LS) ratio is 1.1:1. What is the most likely diagnosis?

Accepted Answer

Cretinism

Answer

Achondroplasia

Answer

Hypothyroidism

Answer

Rickets

Question 10

What condition is likely in a newborn presenting with dry, rough skin, a big tongue and rough hair?

Accepted Answer

Congenital hypothyroidism

Answer

Prader-Willi syndrome

Answer

Edward syndrome

Answer

Galactosemia

Endocrinology — MCQs

Endocrinology — MCQs

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