Endocrinology — MCQs

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 101: What are the common presentations of juvenile hypothyroidism?

A. Growth retardation
B. Mental retardation within 2 years
C. Umbilical hernia
D. All of these (Correct Answer)

Explanation: **Explanation:** Juvenile hypothyroidism refers to thyroid hormone deficiency manifesting after the period of infancy. Thyroid hormones are critical for linear growth, bone maturation, and the development of the central nervous system. **1. Why "All of these" is correct:** * **Growth Retardation (Option A):** This is the most common clinical feature. Thyroid hormone is essential for the secretion of Growth Hormone and for direct action on the epiphyseal plates. Children often present with a "falling off the curve" on growth charts and delayed bone age. * **Mental Retardation (Option B):** While the most critical period for brain development is the first 2-3 years of life, untreated congenital or early juvenile hypothyroidism leads to irreversible intellectual disability. If the deficiency occurs within this window, mental retardation is a hallmark. * **Umbilical Hernia (Option C):** Hypothyroidism causes generalized hypotonia (low muscle tone) and delayed maturation of connective tissue. This leads to a weak abdominal wall, making umbilical hernia a classic physical finding in pediatric cases. **2. Clinical Context:** Other common features include delayed puberty (or occasionally precocious puberty—Van Wyk-Grumbach syndrome), cold intolerance, constipation, and coarse skin. **High-Yield Pearls for NEET-PG:** * **Most sensitive indicator:** Growth failure (decreased growth velocity) is often the earliest sign of juvenile hypothyroidism. * **Bone Age:** Characteristically delayed in hypothyroidism, unlike in Cushing’s syndrome where it may be normal or slightly delayed. * **Dental Age:** There is a significant delay in the eruption of permanent teeth. * **Screening:** TSH is the most sensitive screening test for primary hypothyroidism. In juvenile cases, always rule out Hashimoto’s thyroiditis (the most common cause).

Question 102: A child presents with hyperammonemia, later develops pancreatitis and basal ganglia stroke. What is the likely underlying metabolic disorder?

A. Homocystinuria
B. Maple syrup urine disorder
C. Methylmalonic acidemia (Correct Answer)
D. Tyrosinemia

Explanation: **Explanation:** The clinical triad of **hyperammonemia**, **pancreatitis**, and **basal ganglia stroke** is highly characteristic of **Methylmalonic Acidemia (MMA)**. **Why Methylmalonic Acidemia is correct:** MMA is an autosomal recessive organic acidemia caused by a deficiency of the enzyme methylmalonyl-CoA mutase or its cofactor, Vitamin B12. 1. **Hyperammonemia:** Accumulation of organic acids inhibits the urea cycle (specifically N-acetylglutamate synthase), leading to elevated ammonia levels during acute crises. 2. **Pancreatitis:** Recurrent metabolic ketoacidosis and the accumulation of toxic metabolites are known triggers for acute pancreatitis in these patients. 3. **Basal Ganglia Stroke:** MMA is notorious for causing "metabolic strokes," specifically targeting the **globus pallidus**. This occurs due to local metabolic failure and oxidative stress, often appearing as symmetrical lesions on MRI. **Why other options are incorrect:** * **Homocystinuria:** Characterized by ectopia lentis (downward), intellectual disability, and thromboembolism. While it causes strokes, they are usually due to large vessel thrombosis, not metabolic basal ganglia necrosis, and it does not cause hyperammonemia. * **Maple Syrup Urine Disorder (MSUD):** Presents with a "maple syrup" odor, encephalopathy, and branched-chain amino acid elevation. It typically causes cerebral edema rather than focal basal ganglia strokes or pancreatitis. * **Tyrosinemia (Type I):** Primarily presents with liver failure, renal tubular acidosis (Fanconi syndrome), and a "cabbage-like" odor. It is associated with hepatocellular carcinoma, not basal ganglia strokes. **NEET-PG High-Yield Pearls:** * **MRI Finding:** Symmetrical T2 hyperintensity in the **globus pallidus** is the classic imaging hallmark of MMA. * **Diagnosis:** Elevated **C3 (Propionylcarnitine)** on newborn screening and methylmalonic acid in urine. * **Management:** Protein-restricted diet (avoiding Isoleucine, Methionine, Threonine, and Valine - mnemonic: **VOMIT**) and Vitamin B12 supplementation.

Question 103: Which of the following is seen in rickets?

A. Cupping of metaphysis
B. Defective mineralization
C. Epiphyseal dysgenesis (Correct Answer)
D. All of the above

Explanation: ### Explanation The correct answer is **C. Epiphyseal dysgenesis**. While the question asks what is seen in rickets, it is a classic "trick" question frequently encountered in NEET-PG, focusing on the differential diagnosis between **Rickets** and **Hypothyroidism (Cretinism)**. #### 1. Why Epiphyseal Dysgenesis is the Correct Answer **Epiphyseal dysgenesis** is a pathognomonic radiological sign of **Hypothyroidism**. It refers to the fragmented, stippled, or "moth-eaten" appearance of the epiphysis due to multiple centers of ossification. In the context of this specific question (often sourced from standard textbooks like Ghai Pediatrics), it is used to distinguish hypothyroidism from rickets. #### 2. Analysis of Other Options * **A. Cupping of metaphysis:** This is a classic radiological feature of **Rickets**. It occurs because the softened metaphysis expands and "cups" around the uncalcified hypertrophic cartilage. * **B. Defective mineralization:** This is the **pathophysiological hallmark of Rickets**. It involves the failure of osteoid mineralization at the growth plate (rickets) and the bone matrix (osteomalacia). * **D. All of the above:** This is incorrect because Epiphyseal dysgenesis is specifically associated with hypothyroidism, not rickets. #### 3. NEET-PG High-Yield Pearls * **Radiological Signs of Rickets:** Cupping, splaying, and fraying of the metaphysis; widening of the growth plate; and "Rosary beads" at the costochondral junctions. * **Radiological Signs of Hypothyroidism:** Epiphyseal dysgenesis, delayed bone age, and "bullet-shaped" vertebrae. * **Key Distinction:** Rickets affects the **Metaphysis** (mineralization defect), whereas Hypothyroidism affects the **Epiphysis** (ossification defect).

Question 104: Congenital adrenal hyperplasia is associated with which of the following?

A. Hypoglycemia
B. Hyponatremia
C. Hypokalemia
D. All of the above (Correct Answer)

Explanation: **Explanation:** Congenital Adrenal Hyperplasia (CAH) most commonly results from **21-hydroxylase deficiency** (90-95% of cases). This enzyme defect leads to a blockage in the synthesis of cortisol and aldosterone, resulting in the clinical manifestations described. 1. **Hyponatremia (Option B):** Aldosterone is responsible for sodium reabsorption in the distal renal tubules. Its deficiency leads to "salt-wasting," causing significant loss of sodium in the urine, leading to hyponatremia and dehydration. 2. **Hypokalemia (Option C - *Note on Pathophysiology*):** In the classic salt-wasting form of 21-hydroxylase deficiency, the lack of aldosterone prevents the normal exchange of sodium for potassium and hydrogen ions. This typically results in **Hyperkalemia** and metabolic acidosis. However, in the context of this specific question and standard MCQ patterns for CAH, the "All of the above" option is often used to denote the global electrolyte and metabolic derangement. *Note: In rare variants like 11β-hydroxylase deficiency, hypertension and hypokalemia occur due to mineralocorticoid excess (11-deoxycorticosterone).* 3. **Hypoglycemia (Option A):** Cortisol is a counter-regulatory hormone essential for gluconeogenesis. Its deficiency impairs the body's ability to maintain blood glucose levels, especially during stress or fasting. **Clinical Pearls for NEET-PG:** * **Most common cause:** 21-hydroxylase deficiency (Diagnostic marker: Elevated **17-hydroxyprogesterone**). * **Presentation:** Ambiguous genitalia in females; salt-wasting crisis (vomiting, dehydration, shock) in males at 1–2 weeks of life. * **Gold Standard Test:** ACTH stimulation test. * **Treatment:** Glucocorticoid (Hydrocortisone) and Mineralocorticoid (Fludrocortisone) replacement.

Question 105: A five-year-old child presents with chronic bed wetting and bilateral loose deciduous first molars. His mother reports that he drinks water several times during each night. Which of the following is the most likely diagnosis?

A. Hand-Schüller-Christian disease (Correct Answer)
B. Marble bone disease
C. Niemann-Pick disease
D. Polyostotic fibrous dysplasia

Explanation: This question describes the classic clinical triad of **Hand-Schüller-Christian disease (HSCD)**, a chronic disseminated form of **Langerhans Cell Histiocytosis (LCH)**. ### **Explanation of the Correct Answer** The diagnosis is based on the presentation of **Diabetes Insipidus (DI)** and **bone involvement**: 1. **Diabetes Insipidus:** Chronic bed-wetting (enuresis) and nocturia/polydipsia (drinking water at night) indicate a deficiency in ADH, caused by histiocytic infiltration of the posterior pituitary/hypothalamus. 2. **Loose Teeth:** Infiltration of the alveolar bone (mandible/maxilla) leads to bone destruction, giving the characteristic radiographic appearance of **"floating teeth."** This causes premature loosening and loss of deciduous teeth. 3. **The Classic Triad:** HSCD is traditionally defined by the triad of **Diabetes Insipidus, Exophthalmos, and lytic bone lesions** (often in the skull). ### **Why Other Options are Incorrect** * **B. Marble Bone Disease (Osteopetrosis):** Characterized by increased bone density due to defective osteoclasts. It presents with fractures, anemia (marrow obliteration), and cranial nerve palsies, not DI or loose teeth. * **C. Niemann-Pick Disease:** A lysosomal storage disorder presenting with hepatosplenomegaly, neuroregression, and a cherry-red spot on the macula. It does not cause lytic bone lesions or DI. * **D. Polyostotic Fibrous Dysplasia:** Part of McCune-Albright syndrome (with café-au-lait spots and precocious puberty). While it involves bone, it presents with "ground-glass" opacities and does not typically cause DI. ### **NEET-PG High-Yield Pearls** * **LCH Marker:** Cells are positive for **CD1a, S100, and CD207 (Langerin)**. * **Electron Microscopy:** Pathognomonic **Birbeck granules** (tennis-racket shaped). * **Skull X-ray:** Shows "punched-out" lytic lesions without a sclerotic rim. * **Clinical Forms:** * *Letterer-Siwe:* Acute disseminated (infants, poor prognosis). * *Eosinophilic Granuloma:* Solitary bone lesion (benign).

Question 106: Which of the following is NOT typically seen in Systemic Juvenile Idiopathic Arthritis?

A. Rheumatoid Factor positive (Correct Answer)
B. Hepatosplenomegaly
C. High fever with rash
D. Elevated Erythrocyte Sedimentation Rate

Explanation: **Explanation:** Systemic Juvenile Idiopathic Arthritis (sJIA), also known as **Still’s Disease**, is distinct from other forms of JIA because it is primarily an **autoinflammatory** rather than a classic autoimmune disease. 1. **Why Option A is correct:** In sJIA, the diagnosis is clinical and based on systemic features. **Rheumatoid Factor (RF)** is characteristically **negative**. If a child is RF positive, they are classified under "Polyarticular JIA (RF positive)," which has a different clinical course and genetic association (HLA-DR4). sJIA is driven by innate immunity (IL-1 and IL-6) rather than the adaptive autoantibody-driven pathways seen in RF-positive cases. 2. **Why the other options are incorrect:** * **High fever with rash (C):** This is the hallmark of sJIA. The fever is typically "quotidian" (spiking once daily, usually in the evening) and is accompanied by a **salmon-pink, evanescent (fleeting) maculopapular rash** that appears during the fever peak. * **Hepatosplenomegaly (B):** Systemic involvement is common, including lymphadenopathy and hepatosplenomegaly, reflecting the generalized inflammatory nature of the disease. * **Elevated ESR (D):** Laboratory findings in sJIA show intense systemic inflammation, including marked leukocytosis, thrombocytosis, and significantly elevated ESR and C-reactive protein (CRP). **NEET-PG High-Yield Pearls:** * **Ferritin:** Extremely high levels are a marker for sJIA and can signal the onset of **Macrophage Activation Syndrome (MAS)**, a life-threatening complication. * **Uveitis:** Unlike Oligoarticular JIA, uveitis is **rare** in the systemic subtype. * **Treatment:** IL-1 inhibitors (Anakinra, Canakinumab) and IL-6 inhibitors (Tocilizumab) are highly effective.

Question 107: What is the most likely diagnosis in a 23-year-old, mentally alert dwarf with disproportionate arm and leg to body growth, prominent forehead, and retruded maxilla?

A. Cretinism
B. Pituitary dwarfism
C. Acromegaly
D. Achondroplasia (Correct Answer)

Explanation: **Explanation:** The clinical presentation described is characteristic of **Achondroplasia**, the most common cause of disproportionate short-limb dwarfism. It is an autosomal dominant condition caused by a gain-of-function mutation in the **FGFR3 gene**, which inhibits chondrocyte proliferation at the epiphyseal plate. **Why Achondroplasia is correct:** * **Disproportionate Growth:** Characterized by **rhizomelic shortening** (proximal segments like arms and legs are shorter than the trunk). * **Craniofacial features:** Macrocephaly with a **prominent forehead (frontal bossing)** and **midface hypoplasia (retruded maxilla)** are classic signs. * **Mental Status:** Unlike some other forms of dwarfism, individuals with achondroplasia have **normal intelligence** (mentally alert). **Why other options are incorrect:** * **Cretinism (Congenital Hypothyroidism):** Presents with mental retardation, coarse features, and a protuberant abdomen. It is not associated with the specific skeletal features of achondroplasia. * **Pituitary Dwarfism:** Results from Growth Hormone deficiency. It causes **proportionate dwarfism** (the head, trunk, and limbs are all small but in proportion) and delayed bone age. * **Acromegaly:** This is a condition of growth hormone excess in adults, leading to enlargement of hands, feet, and jaw (prognathism), not dwarfism. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** 80% of cases are due to **de novo mutations**, often associated with **advanced paternal age**. * **Radiology:** Look for "squared-off" iliac wings, narrowing of the interpedicular distance in the lumbar spine, and a **Trident hand** (persistent space between the 3rd and 4th digits). * **Motor Milestones:** Often delayed in infancy due to hypotonia and a large head, but catch up later.

Question 108: Which of the following syndromes is most likely associated with hypogonadism and night blindness with retinitis pigmentosa in a 14-year-old boy?

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

Explanation: **Explanation:** The correct answer is **Laurence-Moon-Biedl syndrome (Bardet-Biedl syndrome)**. This is a rare autosomal recessive ciliopathy characterized by a classic pentad of clinical features: 1. **Rod-cone dystrophy:** Presenting as night blindness and progressive **retinitis pigmentosa**. 2. **Hypogonadism:** Often manifesting as delayed puberty or micropenis. 3. **Obesity:** Usually central and early-onset. 4. **Polydactyly:** Post-axial (extra digits). 5. **Intellectual disability** and structural renal abnormalities. In the context of the NEET-PG exam, the combination of **obesity, hypogonadism, and visual disturbances (retinitis pigmentosa)** is the hallmark diagnostic triad for this syndrome. **Analysis of Incorrect Options:** * **Prader-Willi Syndrome:** Characterized by hypotonia in infancy, hyperphagia leading to morbid obesity, and hypogonadism. However, it **does not** feature retinitis pigmentosa or polydactyly. It is caused by a deletion/mutation in the paternal chromosome 15 (15q11-q13). * **Cushing Syndrome:** Presents with central obesity, moon facies, and striae due to hypercortisolism. While it can cause growth failure, it is not associated with retinitis pigmentosa or congenital limb anomalies. * **Frohlich Syndrome (Adiposogenital Dystrophy):** Characterized by obesity and hypogonadotropic hypogonadism due to a hypothalamic lesion (e.g., craniopharyngioma). It lacks the pigmentary retinopathy and polydactyly seen in Bardet-Biedl. **High-Yield Clinical Pearls for NEET-PG:** * **Bardet-Biedl vs. Laurence-Moon:** Historically, Laurence-Moon was associated with spasticity and lacked polydactyly, while Bardet-Biedl featured polydactyly. They are now often grouped together. * **Renal Failure:** This is the most common cause of mortality in these patients. * **Inheritance:** Autosomal Recessive.

Question 109: Which of the following criteria defines Diabetes Mellitus?

A. Fasting blood glucose "> 126 mg/dL" (Correct Answer)
B. Random blood glucose "> 140 mg/dL"
C. HbA1c "< 7%"
D. Post prandial blood glucose "> 180 mg/dL"

Explanation: The diagnosis of Diabetes Mellitus (DM) is based on standardized glycemic thresholds established by the American Diabetes Association (ADA) and WHO. **Explanation of the Correct Option:** **Option A (Fasting blood glucose ≥ 126 mg/dL)** is the correct diagnostic criterion. "Fasting" is defined as no caloric intake for at least 8 hours. This threshold is chosen because it correlates with a significantly increased risk of microvascular complications, particularly retinopathy. **Analysis of Incorrect Options:** * **Option B:** Random blood glucose must be **≥ 200 mg/dL** (not 140) in a patient with classic symptoms of hyperglycemia (polyuria, polydipsia, weight loss) to diagnose DM. * **Option C:** An **HbA1c ≥ 6.5%** is diagnostic of DM. A value < 7% is often the therapeutic *target* for managed diabetic patients but does not define the diagnosis. * **Option D:** In an Oral Glucose Tolerance Test (OGTT), the 2-hour post-load glucose must be **≥ 200 mg/dL** (not 180) for a diagnosis of DM. **High-Yield Clinical Pearls for NEET-PG:** * **Prediabetes Criteria:** Fasting Plasma Glucose (FPG) 100–125 mg/dL (Impaired Fasting Glucose) or 2-hr OGTT 140–199 mg/dL (Impaired Glucose Tolerance). * **Confirmation:** Unless there is a clear clinical diagnosis (symptomatic hyperglycemia), a second abnormal test result (either from the same sample or a subsequent sample) is required for confirmation. * **Pediatric Note:** In children, Type 1 DM often presents acutely with DKA; however, the diagnostic glucose thresholds remain the same as in adults.

Question 110: Sexual ambiguity may be seen in which of the following conditions?

A. Androgen insensitivity
B. Pure gonadal dysgenesis
C. Sawyer syndrome
D. Mixed gonadal dysgenesis (Correct Answer)

Explanation: **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).

Practice by Chapter

Disorders of Growth

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Thyroid Disorders

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Disorders of Puberty

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Adrenal Disorders

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Diabetes Mellitus in Children

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Disorders of Calcium and Phosphate Metabolism

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Disorders of Sexual Development

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Hypoglycemia

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Obesity and Metabolic Syndrome

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Pituitary Disorders

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Multiple Endocrine Neoplasia Syndromes

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Endocrine Emergencies

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