Endocrinology Practice Questions

Q: Sexual ambiguity may be seen in which of the following conditions?

Mixed gonadal dysgenesis. **Explanation:** **Sexual ambiguity** occurs when there is a mismatch between the genetic sex and the appearance of the external genitalia, usually due to an imbalance in androgen production or action during the critical window of fetal development. **Why Mixed Gonadal Dysgenesis (MGD) is correct:** MGD (typically 45,X/46,XY mosaicism) is one of the most common causes of ambiguous genitalia. It is characterized by a "streak gonad" on one side and a functioning testis on the other. Because the production of Testosterone and Anti-Müllerian Hormone (AMH) is asymmetrical and often insufficient, the external genitalia fail to virilize completely, leading to **ambiguity**. Internal structures usually include a uterus and a mix of Wolffian and Müllerian ducts. **Why the other options are incorrect:** * **Androgen Insensitivity Syndrome (AIS):** In Complete AIS (46,XY), there is a total lack of response to androgens. Consequently, the external genitalia are **completely female**, not ambiguous. * **Pure Gonadal Dysgenesis (46,XX or 46,XY):** These individuals have bilateral streak gonads. Since no hormones (androgens or AMH) are produced, they develop **normal female** internal and external phenotypes (though they remain prepubertal). * **Swyer Syndrome:** This is 46,XY Pure Gonadal Dysgenesis. Due to the failure of testicular development, there is no testosterone or AMH. Patients have a **normal female** phenotype at birth and are only diagnosed later due to primary amenorrhea. **NEET-PG High-Yield Pearls:** * **Most common cause of ambiguous genitalia overall:** Congenital Adrenal Hyperplasia (CAH), specifically 21-hydroxylase deficiency. * **MGD Hallmark:** Presence of a streak gonad and a contralateral testis; high risk of **Gonadoblastoma** (requires prophylactic gonadectomy). * **Swyer Syndrome vs. AIS:** Swyer has a uterus (no AMH), while AIS has a blind-ending vagina and no uterus (AMH is present).

Q: Which of the following is NOT a metabolic abnormality seen in congenital adrenal hyperplasia?

Hypokalemia. **Explanation:** Congenital Adrenal Hyperplasia (CAH), most commonly due to **21-hydroxylase deficiency** (90-95% of cases), results in the impaired synthesis of cortisol and aldosterone. The absence of aldosterone leads to a "salt-wasting" state, which is the key to understanding the metabolic profile. 1. **Why Hypokalemia is the correct answer:** In CAH, the lack of aldosterone prevents the kidneys from excreting potassium and hydrogen ions in exchange for sodium. This leads to **Hyperkalemia**, not hypokalemia. Therefore, hypokalemia is the metabolic abnormality NOT seen in CAH. 2. **Analysis of incorrect options:** * **Hyponatremia (C):** Aldosterone deficiency leads to failure of sodium reabsorption in the distal renal tubules, causing significant sodium loss in the urine. * **Hypotension (A):** The combination of hyponatremia and water loss (due to osmotic diuresis) leads to volume depletion, dehydration, and eventually hypotension or hypovolemic shock. * **Metabolic Acidosis (D):** Since aldosterone is required for the secretion of $H^+$ ions into the urine, its absence results in the retention of $H^+$ ions, leading to a **normal anion gap metabolic acidosis**. **High-Yield Clinical Pearls for NEET-PG:** * **Most common enzyme deficiency:** 21-hydroxylase deficiency (presents with virilization and salt-wasting). * **The "Exception" Rule:** In the rare **11-$\beta$-hydroxylase deficiency**, patients present with **hypertension and hypokalemia** because of the buildup of 11-deoxycorticosterone (a potent mineralocorticoid). * **Diagnostic Marker:** Elevated levels of **17-hydroxyprogesterone (17-OHP)** is the gold standard for screening/diagnosis of 21-hydroxylase deficiency. * **Clinical Presentation:** Ambiguous genitalia in females; salt-wasting crisis (vomiting, dehydration) in males at 1–2 weeks of life.

Q: What is the most common central nervous system tumor associated with precocious puberty?

Hamartoma. **Explanation:** **Correct Answer: D. Hamartoma** **Medical Concept:** Hypothalamic hamartomas are the most common CNS tumors associated with **GnRH-dependent (Central) Precocious Puberty**. These are non-neoplastic congenital malformations consisting of ectopic neural tissue (neurons and glia) located in the region of the tuber cinereum or floor of the third ventricle. They act as "ectopic GnRH pulse generators," containing neurons that autonomously secrete GnRH in a pulsatile fashion, thereby prematurely activating the pituitary-gonadal axis. **Analysis of Incorrect Options:** * **A. Astrocytoma:** While optic gliomas and hypothalamic astrocytomas (often associated with NF-1) can cause precocious puberty by disrupting inhibitory pathways to the hypothalamus, they are less common causes than hamartomas. * **B. Neurofibroma:** Neurofibromatosis Type 1 (NF-1) is associated with precocious puberty, but the underlying cause is typically an **optic pathway glioma** (astrocytoma), not a neurofibroma itself. * **C. Ependymoma:** These tumors typically arise from the lining of the ventricles. While they can cause increased intracranial pressure or hydrocephalus, they are rarely implicated as a primary cause of precocious puberty. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** Hypothalamic hamartomas are classically associated with **Gelastic Seizures** (pathognomonic "laughing" seizures), precocious puberty, and developmental delay. * **Diagnosis:** MRI is the gold standard; hamartomas appear as a pedunculated mass at the base of the hypothalamus that is isointense to gray matter on T1-weighted images and does not enhance with contrast. * **Treatment:** The drug of choice for central precocious puberty is **long-acting GnRH agonists** (e.g., Leuprolide), which desensitize the pituitary GnRH receptors.

Q: Which of the following findings is consistent with a diagnosis of delayed puberty?

Menarche delayed beyond 16 years of age. ### Explanation **Delayed puberty** is defined by the absence of secondary sexual characteristics by an age that is 2 to 2.5 standard deviations above the mean for the population. #### 1. Why Option B is Correct In girls, delayed puberty is clinically diagnosed if: * There is **no breast development (Thelarche)** by age **13**. * There is a gap of >5 years between thelarche and menarche. * **Menarche** has not occurred by age **16** (regardless of secondary sexual development). Therefore, menarche delayed beyond 16 years is a definitive criterion for delayed puberty. #### 2. Analysis of Incorrect Options * **Option A:** Breast budding (Thelarche) at age 10 is perfectly normal. The normal range for thelarche is 8–13 years. * **Option C:** Menarche typically occurs 2–2.5 years after thelarche (Stage B2). Menarche occurring 1 year after budding is slightly early but does not constitute "delayed" puberty. * **Option D:** FSH levels vary significantly based on the etiology. In **Hypogonadotropic Hypogonadism** (e.g., Kallmann syndrome), FSH is low ( 20 mIU/mL). A value "less than 20" is too non-specific to define delayed puberty. #### 3. High-Yield Clinical Pearls for NEET-PG * **Most Common Cause:** Constitutional Delay of Growth and Puberty (CDGP) is the most common cause in both sexes (characterized by "late bloomers" with delayed bone age). * **Male Criteria:** Delayed puberty in boys is defined as lack of testicular enlargement (**<4 mL or <2.5 cm**) by age **14**. * **Sequence in Girls:** Thelarche $\rightarrow$ Adrenarche/Pubarche $\rightarrow$ Growth Spurt $\rightarrow$ Menarche. * **Sequence in Boys:** Testicular enlargement $\rightarrow$ Penile growth $\rightarrow$ Pubarche $\rightarrow$ Growth Spurt.

Q: A 16-month-old child presents with excessive thirst and frequent, large voids of urine. Examination reveals dehydration, but no history of vomiting or diarrhea. What is the most likely cause?

Diabetes insipidus. **Explanation:** The clinical presentation of **excessive thirst (polydipsia)** and **frequent, large voids (polyuria)** in a child without gastrointestinal losses (vomiting/diarrhea) strongly suggests a disorder of water homeostasis. **Why Diabetes Insipidus (DI) is correct:** Diabetes Insipidus is characterized by either a deficiency of Antidiuretic Hormone (ADH) from the posterior pituitary (Central DI) or a lack of renal response to ADH (Nephrotic DI). This leads to an inability to concentrate urine, resulting in the excretion of large volumes of dilute urine. In infants and toddlers, this manifests as dehydration, irritability (relieved by drinking water), and polyuria. **Why the other options are incorrect:** * **Water Intoxication:** This occurs due to excessive intake of free water, leading to hyponatremia and fluid overload, not dehydration. * **Nephrotic Syndrome:** Typically presents with edema (due to hypoalbuminemia), proteinuria, and decreased urine output (oliguria), rather than polyuria and dehydration. * **Diabetes Mellitus (DM):** While DM causes polyuria (osmotic diuresis due to glycosuria) and polydipsia, it is usually associated with weight loss, polyphagia, and often ketoacidosis in children. DI is the more specific diagnosis for pure water loss leading to dehydration in this age group. **High-Yield Clinical Pearls for NEET-PG:** * **Water Deprivation Test:** The gold standard for diagnosing DI and differentiating it from primary polydipsia. * **Desmopressin (dDAVP) Challenge:** Used to differentiate Central DI (responds to dDAVP) from Nephrogenic DI (no response). * **Initial Sign in Infants:** Unexplained fever and "wet diapers" that are heavy but contain very pale, dilute urine. * **Biochemical Hallmark:** High serum osmolality (>300 mOsm/kg) with low urine osmolality (<300 mOsm/kg).

Q: Which of the following conditions is related to an enzyme deficiency and involves periodontal destruction around primary teeth?

Hypophosphatasia. **Explanation:** **Hypophosphatasia** is an inherited metabolic bone disease caused by a deficiency of the **Tissue-Nonspecific Alkaline Phosphatase (TNSALP)** enzyme. The hallmark clinical feature in children is the **premature loss of primary teeth** (specifically the incisors) before age 4. This occurs due to defective cementum formation, which prevents the periodontal ligament from attaching the tooth to the alveolar bone, leading to periodontal destruction and exfoliation without significant root resorption. **Analysis of Incorrect Options:** * **Cyclic Neutropenia (B):** While it causes periodic oral ulcers and periodontal bone loss due to a drop in neutrophil counts, it is a hematological disorder, not an enzyme deficiency. * **Juvenile Periodontitis (C):** Now termed Aggressive Periodontitis, this is primarily an inflammatory/infectious condition associated with *Aggregatibacter actinomycetemcomitans*, not an enzyme defect. * **Papillon-Lefevre Syndrome (D):** This involves severe periodontitis and palmoplantar keratoderma. While it is caused by a mutation in the *Cathepsin C* gene (a protease), the classic NEET-PG presentation for "enzyme deficiency with early tooth loss" specifically points toward Hypophosphatasia due to the diagnostic marker of low serum alkaline phosphatase. **Clinical Pearls for NEET-PG:** * **Diagnostic Marker:** Low serum Alkaline Phosphatase (ALP) levels and elevated urinary phosphoethanolamine. * **Radiology:** "Beaten copper" appearance of the skull and "bowing" of long bones (Rickets-like features). * **Key Differentiator:** In Hypophosphatasia, teeth fall out with **intact roots**, unlike normal exfoliation where roots are resorbed.

Q: Which of the following conditions commonly presents with a large tongue?

Hypothyroidism. **Explanation:** **Macroglossia (a large tongue)** is a classic clinical hallmark of **Congenital Hypothyroidism**. The underlying mechanism involves the accumulation of **glycosaminoglycans** (such as hyaluronic acid) within the interstitial tissues of the tongue. This occurs due to a decreased metabolic rate and altered protein metabolism, leading to a thickened, protruding tongue that can cause feeding difficulties and noisy breathing (stridor). **Analysis of Incorrect Options:** * **Turner Syndrome (45, XO):** Characterized by a high-arched palate, webbed neck, and short stature, but not macroglossia. * **Treacher Collins Syndrome:** A craniofacial disorder characterized by mandibular hypoplasia (micrognathia) and malformed ears. The tongue is of normal size, but the small jaw may make it appear prominent or cause it to fall back (glossoptosis). * **Congenital Syphilis:** Presents with features like Hutchinson’s teeth, mulberry molars, and saddle nose, but macroglossia is not a feature. **High-Yield Clinical Pearls for NEET-PG:** * **Differential Diagnosis of Macroglossia:** Remember the mnemonic **"BIG TONGUE"**: **B**eckwith-Wiedemann Syndrome (most common overgrowth syndrome), **I**diopathic, **G**lycogen storage disease (Pompe disease), **T**risomy 21 (Down Syndrome), **O**bstruction (Hemangioma/Lymphangioma), **N**eoplasia, **G**rave’s disease/Hypothyroidism, **U**nusual (Amyloidosis), **E**ndocrine (Acromegaly). * **Congenital Hypothyroidism:** Also presents with a large posterior fontanelle, prolonged physiological jaundice, umbilical hernia, and constipation. It is the most common preventable cause of intellectual disability. * **Screening:** The best time for neonatal screening (TSH) is after 48–72 hours of birth to avoid the physiological TSH surge.

Q: Which of the following is NOT a characteristic of Mauriac's syndrome?

Cardiomegaly. **Explanation:** **Mauriac’s Syndrome** is a rare complication of Type 1 Diabetes Mellitus, typically seen in children and adolescents with poorly controlled glycemic levels. It is characterized by a classic tetrad of clinical features. **Why Cardiomegaly is the correct answer:** Cardiomegaly is **not** a feature of Mauriac’s Syndrome. While chronic diabetes can lead to long-term cardiovascular complications in adults, the specific pediatric presentation of Mauriac’s Syndrome involves metabolic and growth disturbances rather than structural heart enlargement. **Analysis of incorrect options:** * **A. Diabetes:** Poorly controlled Type 1 Diabetes is the prerequisite for this syndrome. The underlying pathophysiology involves periods of hyperglycemia followed by supraphysiological insulin doses, leading to glycogen deposition. * **B. Obesity:** Patients typically present with **cushingoid features**, including a "moon face" and truncal obesity (fat redistribution), despite having a low BMI or appearing wasted in the extremities. * **C. Dwarfism:** Growth failure or **stunted growth** is a hallmark. This occurs due to a combination of relative insulin deficiency, low IGF-1 levels, and delayed bone age. **Clinical Pearls for NEET-PG:** * **The Tetrad:** 1. Poorly controlled Type 1 Diabetes, 2. Growth failure (Dwarfism), 3. Delayed puberty, and 4. **Hepatomegaly** (due to glycogenosis/fatty liver). * **Key Diagnostic Sign:** Massive hepatomegaly is the most striking feature, caused by glycogen trapping in hepatocytes. * **Reversibility:** Most features, including growth and liver size, can improve significantly with optimized glycemic control and intensive insulin therapy.

Q: Which of the following is NOT a feature of Hypothyroidism?

All of the above are features of Hypothyroidism. **Explanation:** Congenital hypothyroidism (CH) is one of the most common treatable causes of intellectual disability. The clinical features of hypothyroidism in children are primarily due to a generalized slowing of metabolic processes and delayed skeletal maturation. **Why the correct answer is D:** All the listed options are classic clinical manifestations of hypothyroidism: * **Delayed Dentition:** Thyroid hormones are essential for bone maturation and tooth eruption. Deficiency leads to delayed appearance of deciduous and permanent teeth. * **Widened Fontanelle:** Hypothyroidism causes delayed ossification of the skull bones, leading to large anterior and posterior fontanelles. A posterior fontanelle >0.5 cm is a highly sensitive early sign of CH. * **Distended Abdomen:** This occurs due to generalized hypotonia (floppy baby) and slowed gastrointestinal motility, which often presents as constipation and an umbilical hernia. **Why other options are incorrect:** Options A, B, and C are incorrect because they are all established features of the disease. Since the question asks which is *NOT* a feature, and all are present, "All of the above" is the only logically sound choice. **High-Yield Clinical Pearls for NEET-PG:** * **Early Signs:** Prolonged physiological jaundice (most common early sign), poor feeding, and lethargy. * **Classic Triad:** Coarse facies, macroglossia (large tongue), and umbilical hernia. * **Skeletal Age:** Delayed bone age is a hallmark; look for the absence of the distal femoral epiphysis at birth. * **Screening:** The best time for neonatal screening (TSH) is between **48–72 hours** of life to avoid the physiological TSH surge. * **Treatment:** Levothyroxine is the drug of choice; the goal is to maintain T4 in the upper half of the normal range to ensure optimal brain development.

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 the diagnosis?

Deoxycortisol. The clinical presentation of **precocious puberty** (virilization) combined with **hypertension** in a young child is the classic hallmark of **11β-hydroxylase deficiency**, the second most common cause of Congenital Adrenal Hyperplasia (CAH). ### Why Deoxycortisol is Correct In 11β-hydroxylase deficiency, the conversion of **11-deoxycortisol to cortisol** and **11-deoxycorticosterone (DOC) to corticosterone** is blocked. This leads to: 1. **Excess Androgens:** Shunting of precursors toward the androgen pathway causes precocious puberty/virilization. 2. **Hypertension:** The accumulation of **11-deoxycorticosterone (DOC)**, a potent mineralocorticoid, causes salt and water retention, leading to high blood pressure. 3. **Diagnosis:** Elevated levels of **11-deoxycortisol** in the blood are diagnostic for this specific enzyme defect. ### Why Other Options are Incorrect * **17-Hydroxyprogesterone (17-OHP):** This is the screening marker for **21-hydroxylase deficiency**. While 21-hydroxylase deficiency also causes precocious puberty, it is typically associated with **hypotension** (salt-wasting) rather than hypertension. * **Cortisol:** Cortisol levels are typically low or low-normal in all forms of CAH due to the enzymatic blocks; it is not a specific diagnostic marker for the subtype. * **Aldosterone:** In 11β-hydroxylase deficiency, aldosterone levels are actually **low** because the excess DOC suppresses the Renin-Angiotensin-Aldosterone System (RAAS). ### NEET-PG High-Yield Pearls * **21-Hydroxylase Deficiency:** Most common CAH; Virilization + **Hypotension** (Salt-wasting). * **11β-Hydroxylase Deficiency:** Virilization + **Hypertension**. * **17α-Hydroxylase Deficiency:** **Hypertension** + Delayed Puberty (No virilization; decreased sex hormones). * **Mnemonic:** If the enzyme starts with **1** (11, 17), it causes **Hypertension**. If the enzyme ends with **1** (11, 21), it causes **Virilization**.

Question 1

Sexual ambiguity may be seen in which of the following conditions?

Accepted Answer

Mixed gonadal dysgenesis

Answer

Androgen insensitivity

Answer

Pure gonadal dysgenesis

Answer

Sawyer syndrome

Question 2

Which of the following is NOT a metabolic abnormality seen in congenital adrenal hyperplasia?

Accepted Answer

Hypokalemia

Answer

Hypotension

Answer

Hyponatremia

Answer

Metabolic acidosis

Question 3

What is the most common central nervous system tumor associated with precocious puberty?

Accepted Answer

Hamartoma

Answer

Astrocytoma

Answer

Neurofibroma

Answer

Ependymoma

Question 4

Which of the following findings is consistent with a diagnosis of delayed puberty?

Accepted Answer

Menarche delayed beyond 16 years of age

Answer

Breast budding in a 10-year-old girl

Answer

Menarche occurring 1 year after breast budding

Answer

FSH values less than 20 mIU/mL

Question 5

A 16-month-old child presents with excessive thirst and frequent, large voids of urine. Examination reveals dehydration, but no history of vomiting or diarrhea. What is the most likely cause?

Accepted Answer

Diabetes insipidus

Answer

Water intoxication

Answer

Nephrotic syndrome

Answer

Diabetes mellitus

Question 6

Which of the following conditions is related to an enzyme deficiency and involves periodontal destruction around primary teeth?

Accepted Answer

Hypophosphatasia

Answer

Cyclic neutropenia

Answer

Juvenile periodontitis

Answer

Papillon-Lefevre syndrome

Question 7

Which of the following conditions commonly presents with a large tongue?

Accepted Answer

Hypothyroidism

Answer

Turner syndrome

Answer

Treacher Collins syndrome

Answer

Congenital syphilis

Question 8

Which of the following is NOT a characteristic of Mauriac's syndrome?

Accepted Answer

Cardiomegaly

Answer

Diabetes

Answer

Obesity

Answer

Dwarfism

Question 9

Which of the following is NOT a feature of Hypothyroidism?

Accepted Answer

All of the above are features of Hypothyroidism

Answer

Delayed dentition

Answer

Widened fontanelle

Answer

Distended abdomen

Question 10

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 the diagnosis?

Accepted Answer

Deoxycortisol

Answer

17-Hydroxyprogesterone

Answer

Cortisol

Answer

Aldosterone

Endocrinology — MCQs

Endocrinology — MCQs

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