Endocrinology — MCQs

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 921: Which of the following hormone productions is noted in Cushing's Syndrome?

A. Decrease production of cortisol
B. Increase production of cortisol (Correct Answer)
C. Excessive production of epinephrine
D. Excessive production of vasopressin

Explanation: **Explanation:** **Cushing’s Syndrome** is a clinical state resulting from chronic exposure to excessive levels of glucocorticoids [3]. The hallmark of this condition is the **increased production of cortisol**, regardless of the underlying cause (e.g., pituitary adenoma, adrenal tumor, or ectopic ACTH production) [4]. Cortisol is a steroid hormone produced by the *zona fasciculata* of the adrenal cortex. Its overproduction leads to the classic constellation of symptoms including central obesity, moon facies, buffalo hump, and purple striae [2]. **Analysis of Options:** * **Option A (Incorrect):** Decreased production of cortisol is characteristic of **Addison’s Disease** (Primary Adrenal Insufficiency), which presents with hyperpigmentation, hypotension, and weight loss. * **Option C (Incorrect):** Excessive production of epinephrine (and norepinephrine) is the defining feature of **Pheochromocytoma**, a tumor of the adrenal medulla or sympathetic ganglia, presenting with episodic hypertension, palpitations, and diaphoresis [1]. * **Option D (Incorrect):** Excessive production of vasopressin (ADH) leads to **SIADH** (Syndrome of Inappropriate Antidiuretic Hormone), characterized by hyponatremia and concentrated urine, often associated with small cell lung cancer. **High-Yield NEET-PG Pearls:** * **Cushing’s Disease vs. Syndrome:** Cushing’s *Disease* specifically refers to a pituitary adenoma secreting ACTH [2]. Cushing’s *Syndrome* is the broad term for hypercortisolism from any source. * **Screening Tests:** The most sensitive initial tests are the **24-hour urinary free cortisol**, the **Overnight Dexamethasone Suppression Test (ODST)**, and late-night salivary cortisol [5]. * **Pseudo-Cushing’s:** Conditions like chronic alcoholism and severe depression can mimic the biochemical findings of Cushing’s syndrome.

Question 922: Gynaecomastia may be seen in patients with all of the following conditions except:

A. Cimetidine therapy
B. Cirrhosis of the liver
C. Klinefelter's syndrome
D. Turner's syndrome (Correct Answer)

Explanation: The correct answer is **D. Turner’s Syndrome**. Gynecomastia is defined as the benign proliferation of glandular breast tissue in males, resulting from an imbalance between estrogen and androgen action. **Why Turner’s Syndrome is the correct answer:** Turner’s syndrome (45, XO) occurs in **phenotypic females** [1]. Since gynecomastia is a clinical finding specific to males, it cannot occur in patients with Turner’s syndrome [5]. Furthermore, these patients typically present with "streak ovaries" and primary amenorrhea due to estrogen deficiency, leading to a lack of breast development (hypoplasia) rather than enlargement [4]. **Analysis of Incorrect Options:** * **Cimetidine therapy:** Cimetidine is a classic pharmacological cause of gynecomastia. It acts as a weak anti-androgen by blocking androgen receptors and inhibiting the cytochrome P450 enzyme, which slows the peripheral metabolism of estrogen. * **Cirrhosis of the liver:** In chronic liver disease, gynecomastia occurs due to two mechanisms: (1) the liver's inability to degrade androstenedione, leading to increased peripheral conversion to estrogen, and (2) increased production of Sex Hormone Binding Globulin (SHBG), which lowers free testosterone levels. * **Klinefelter’s syndrome (47, XXY):** This is the most common congenital cause of primary hypogonadism [3]. The extra X chromosome leads to testicular dysgenesis, low testosterone, and elevated gonadotropins (FSH/LH). The resulting high LH stimulates aromatase activity, increasing estrogen levels and causing gynecomastia in approximately 50-80% of cases. **NEET-PG High-Yield Pearls:** * **Drugs causing gynecomastia (Mnemonic: DISCO):** **D**igoxin, **I**soniazid, **S**pironolactone (most common), **C**imetidine, **O**estrogens/Ketoconazole. * **Klinefelter’s Syndrome** carries a 20-50 times higher risk of male breast cancer compared to the general male population [3]. * **Physiological gynecomastia** occurs at three stages: Neonatal, Pubertal, and Senile (old age) [2].

Question 923: All of the following familial syndromes are associated with the development of pheochromocytomas except?

A. MEN II A
B. Von Hippel-Lindau syndrome
C. MEN Type II B
D. Prader-Willi syndrome (Correct Answer)

Explanation: **Explanation:** The correct answer is **Prader-Willi syndrome (D)**. Pheochromocytomas are catecholamine-secreting tumors of the adrenal medulla. While most cases are sporadic, approximately 30-40% are associated with hereditary germline mutations. [2] **Why Prader-Willi syndrome is the correct answer:** Prader-Willi syndrome is a genetic disorder caused by the loss of function of specific genes on **chromosome 15** (paternal imprinting). It is clinically characterized by hyperphagia leading to obesity, intellectual disability, and hypogonadotropic hypogonadism. [1], [3] It has **no association** with the development of pheochromocytomas or paragangliomas. **Why the other options are incorrect:** * **MEN IIA & IIB:** Both Multiple Endocrine Neoplasia Type 2A and 2B are caused by mutations in the **RET proto-oncogene**. Pheochromocytoma occurs in approximately 50% of these patients (usually bilateral and multicentric). * **Von Hippel-Lindau (VHL) syndrome:** Caused by a mutation in the **VHL tumor suppressor gene** (Chromosome 3). It is a major cause of familial pheochromocytoma (Type 2 VHL), often presenting at a young age. [3] **High-Yield Clinical Pearls for NEET-PG:** * **Rule of 10s (Traditional):** 10% are bilateral, 10% are extra-adrenal (paragangliomas), 10% are malignant, and 10% occur in children. *Note: The "10% familial" rule is now outdated, as genetic causes are closer to 35-40%.* [2] * **Neurofibromatosis Type 1 (NF1):** Another key syndrome associated with pheochromocytoma (though less common than in MEN2 or VHL). * **SDH Mutations:** Mutations in Succinate Dehydrogenase (SDHB, SDHD) are high-yield causes of familial paraganglioma syndromes. [2] * **Diagnosis:** The most sensitive initial screening test is **plasma free metanephrines**.

Question 924: HNF-1b gene defect is seen in which type of MODY?

A. MODY 2
B. MODY 3
C. MODY 4
D. MODY 5 (Correct Answer)

Explanation: **Explanation:** Maturity-Onset Diabetes of the Young (MODY) is a group of monogenic disorders characterized by non-insulin-dependent diabetes occurring typically before age 25, inherited in an autosomal dominant pattern [1]. **Correct Option: D (MODY 5)** MODY 5 is caused by a mutation in the **HNF-1β (Hepatocyte Nuclear Factor-1 beta)** gene. This subtype is unique because it is often referred to as the **"Renal Cysts and Diabetes (RCAD) syndrome."** Unlike other forms of MODY, it involves multi-organ developmental anomalies, most notably renal cysts, urogenital tract abnormalities (like bicornuate uterus), and pancreatic atrophy. **Incorrect Options:** * **MODY 2 (Option A):** Caused by a defect in the **Glucokinase (GCK)** gene. It typically presents as mild, stable fasting hyperglycemia that rarely requires treatment and is not associated with complications. * **MODY 3 (Option B):** Caused by a defect in the **HNF-1α** gene. This is the **most common** form of MODY worldwide. It is characterized by a low renal threshold for glucose (glycosuria) and extreme sensitivity to Sulfonylureas. * **MODY 4 (Option C):** Caused by a defect in the **IPF-1 (Insulin Promoter Factor-1)** gene, also known as PDX1. It is a rare form involving impaired beta-cell development. **High-Yield Clinical Pearls for NEET-PG:** * **Most Common MODY:** MODY 3 (HNF-1α). * **Most Common in Pregnancy:** MODY 2 (GCK). * **Drug of Choice:** Sulfonylureas are the first-line treatment for MODY 1 and MODY 3. * **Key Diagnostic Clue for MODY 5:** Presence of renal anomalies (cysts) or genitourinary malformations alongside diabetes.

Question 925: Which of the following is NOT a feature of Cushing syndrome?

A. Hypercoagulability
B. Eosinopenia
C. Hyperpigmentation of knuckles
D. Leukopenia (Correct Answer)

Explanation: **Explanation:** The correct answer is **Leukopenia**. In Cushing syndrome (hypercortisolism), glucocorticoids actually cause **Leukocytosis** (an increase in white blood cell count), specifically due to **neutrophilia**. This occurs because steroids decrease the adherence of neutrophils to the vascular endothelium, causing them to move from the "marginal pool" into the "circulating pool" (demargination). **Analysis of Options:** * **A. Hypercoagulability:** Glucocorticoids increase the levels of clotting factors (like Factor VIII and von Willebrand factor) and decrease fibrinolytic activity. This places patients at a high risk for venous thromboembolism (VTE). * **B. Eosinopenia:** Glucocorticoids lead to the sequestration of eosinophils in the spleen and lungs, resulting in a decreased peripheral eosinophil count. They also cause **lymphopenia** and **monocytopenia**. * **C. Hyperpigmentation of knuckles:** This is a classic feature of **ACTH-dependent** Cushing syndrome (e.g., Cushing disease or Ectopic ACTH) [1]. Excess ACTH acts on melanocortin-1 receptors due to its structural similarity to MSH (Melanocyte-Stimulating Hormone), leading to hyperpigmentation, particularly in skin folds, scars, and knuckles. **Clinical Pearls for NEET-PG:** * **The "Cushingoid" Hemogram:** Look for Neutrophilia, Lymphopenia, and Eosinopenia. * **Hypokalemic Metabolic Alkalosis:** Often seen in ectopic ACTH secretion due to the mineralocorticoid effects of high cortisol levels. * **Screening Test of Choice:** 24-hour urinary free cortisol or Low-Dose Dexamethasone Suppression Test (LDDST) [2], [3]. * **Proximal Myopathy:** Cortisol causes muscle wasting (proteolysis), leading to difficulty climbing stairs or rising from a chair, while distal muscles are relatively spared [1].

Question 926: What is the differentiating feature between ectopic ACTH secretion and Cushing syndrome?

A. Hypokalemic alkalosis (Correct Answer)
B. Clinical features of Cushing syndrome
C. Hyperpigmentation
D. Hypertension

Explanation: ### Explanation The primary differentiating feature between ectopic ACTH secretion (often due to Small Cell Carcinoma of the lung) and classic Cushing’s disease (pituitary adenoma) is the **severity and rapidity of onset** of biochemical abnormalities. **1. Why Hypokalemic Alkalosis is the Correct Answer:** In ectopic ACTH secretion, ACTH levels are typically extremely high [2]. This leads to massive elevations of cortisol that overwhelm the **11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2)** enzyme in the kidneys. Normally, this enzyme converts cortisol to inactive cortisone to prevent it from binding to mineralocorticoid receptors. When overwhelmed, cortisol acts like aldosterone, causing profound potassium excretion and hydrogen ion loss, leading to **severe hypokalemic metabolic alkalosis**. While seen in only 10% of Cushing’s disease cases, it is present in over 70–90% of ectopic ACTH cases. **2. Analysis of Incorrect Options:** * **B. Clinical features of Cushing syndrome:** Ectopic ACTH often presents with "Galloping Cushing’s." Because the underlying malignancy (e.g., lung cancer) progresses rapidly, patients often present with weight loss and cachexia rather than the classic centripetal obesity and buffalo hump. * **C. Hyperpigmentation:** This occurs in both Cushing’s disease and ectopic ACTH because ACTH is derived from POMC, which also produces Melanocyte Stimulating Hormone (MSH). It does not differentiate the two. * **D. Hypertension:** This is a common feature in all forms of hypercortisolism due to increased vascular sensitivity to catecholamines and mineralocorticoid effects. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of Ectopic ACTH:** Small cell carcinoma of the lung [1]. * **High-dose Dexamethasone Suppression Test (HDDST):** Suppresses cortisol in Cushing’s disease (pituitary) but **fails** to suppress it in ectopic ACTH secretion. * **CRH Stimulation Test:** ACTH and cortisol rise in Cushing’s disease but show no response in ectopic ACTH.

Question 927: Hypoglycemia is seen in which of the following conditions?

A. Acromegaly
B. Cushing syndrome
C. Hypothyroidism
D. Hypopituitarism (Correct Answer)

Explanation: Hypopituitarism leads to a deficiency of multiple hormones, most notably **Growth Hormone (GH)** and **Adrenocorticotropic Hormone (ACTH)**. Both GH and Cortisol (stimulated by ACTH) are **counter-regulatory hormones** that oppose the action of insulin. They promote gluconeogenesis and glycogenolysis while decreasing peripheral glucose uptake. In hypopituitarism, the absence of these hormones results in increased insulin sensitivity and a failure to mobilize glucose during fasting, leading to **hypoglycemia** [1]. This is particularly common in pediatric cases or during stressful physiological states in adults. **2. Why the Other Options are Incorrect:** * **A. Acromegaly:** Caused by an excess of Growth Hormone. Since GH is a counter-regulatory hormone, its excess leads to insulin resistance and **hyperglycemia** (secondary diabetes mellitus). * **B. Cushing Syndrome:** Characterized by excess Cortisol. Cortisol stimulates gluconeogenesis and antagonizes insulin, leading to **hyperglycemia** and "steroid-induced diabetes." * **C. Hypothyroidism:** While severe hypothyroidism (Myxedema coma) can occasionally present with hypoglycemia due to slowed metabolism, it is not a classic or primary feature. In standard clinical scenarios, hypothyroidism is more commonly associated with weight gain and dyslipidemia rather than significant glucose derangement. **Clinical Pearls for NEET-PG:** * **Whipple’s Triad:** Essential for diagnosing hypoglycemia (Symptoms + low plasma glucose + relief of symptoms after glucose administration) [2]. * **Addison’s Disease:** Primary adrenal insufficiency is a major cause of hypoglycemia due to isolated cortisol deficiency. * **Insulinoma vs. Factitious Disorder:** High C-peptide levels are seen in Insulinoma, whereas low C-peptide with high insulin suggests exogenous insulin injection. * **Growth Hormone in Children:** Hypoglycemia in a neonate/child with a small phallus should raise suspicion of congenital hypopituitarism.

Question 928: A 12-year-old girl presents with mood and emotional liability and a golden brown discoloration in Descemet's membrane. What is the most likely diagnosis?

A. Fabry's disease
B. Wilson's disease (Correct Answer)
C. Glycogen storage disease
D. Acute rheumatic fever

Explanation: ### Explanation **Correct Answer: B. Wilson’s Disease** The clinical presentation of **mood/emotional lability** (psychiatric symptoms) combined with a **golden-brown discoloration in Descemet’s membrane** is pathognomonic for Wilson’s disease [1]. This ocular finding is known as the **Kayser-Fleischer (KF) ring**, caused by the deposition of copper in the cornea. Wilson’s disease is an autosomal recessive disorder involving a mutation in the **ATP7B gene** on chromosome 13. This leads to impaired biliary copper excretion and deficient incorporation of copper into ceruloplasmin. The resulting copper overload primarily affects the **liver** (cirrhosis), the **brain** (basal ganglia degeneration leading to movement disorders or psychiatric issues), and the **eyes** [1]. **Why the other options are incorrect:** * **A. Fabry’s disease:** An X-linked lysosomal storage disorder characterized by angiokeratomas, peripheral neuropathy, and renal failure. The classic ocular finding is **cornea verticillata** (vortex keratopathy), not KF rings. * **C. Glycogen storage disease:** These typically present with hypoglycemia, hepatomegaly, and growth retardation. They do not cause copper deposition in the cornea. * **D. Acute rheumatic fever:** Presents with carditis, polyarthritis, chorea, and erythema marginatum. It does not involve corneal pigment changes. **NEET-PG High-Yield Pearls:** * **Best Initial Test:** Serum Ceruloplasmin (decreased; <20 mg/dL). * **Gold Standard Diagnostic:** Liver biopsy (increased copper content >250 µg/g dry weight). * **Most Sensitive Screening:** 24-hour urinary copper excretion (>100 µg/day). * **MRI Brain Finding:** "Face of the Giant Panda" sign in the midbrain. * **Treatment:** Chelating agents like **D-Penicillamine** (first-line) or Trientine; Zinc is used for maintenance.

Question 929: Which investigation is useful for detecting extra-adrenal pheochromocytoma?

A. Ultrasound (USG)
B. Contrast-enhanced computed tomography (CCT)
C. T2-weighted magnetic resonance imaging (MRI) with gadolinium contrast (Correct Answer)
D. Metaiodobenzylguanidine (MIBG) scan

Explanation: ### Explanation **Pheochromocytoma** is a catecholamine-secreting tumor of the adrenal medulla. When these tumors arise from extra-adrenal chromaffin tissue (paraganglia), they are termed **paragangliomas** [1]. #### Why MRI is the Correct Answer MRI is the imaging modality of choice for detecting extra-adrenal pheochromocytomas (paragangliomas) due to its superior soft-tissue contrast and specific signal characteristics. On **T2-weighted MRI**, these tumors typically exhibit a very high signal intensity, famously described as the **"Light Bulb Sign."** MRI is particularly useful for localizing tumors in the neck, thorax, or pelvis and is safer than CT in patients with contrast allergies or pregnancy. The use of gadolinium further helps in delineating the vascularity of the lesion. #### Analysis of Incorrect Options * **A. Ultrasound (USG):** USG has low sensitivity and specificity for retroperitoneal or small extra-adrenal lesions. It is generally used only as an initial screening tool for large adrenal masses. * **B. CECT:** While CT is excellent for adrenal tumors, it is less sensitive than MRI for extra-adrenal sites [1]. Furthermore, ionic contrast can theoretically trigger a hypertensive crisis in unblocked patients (though modern non-ionic contrast is safer). * **C. MIBG Scan:** While MIBG is highly specific for functional localization, it is a **nuclear imaging** study. In the context of "detecting" (anatomical localization) extra-adrenal sites, MRI is preferred for its superior resolution. MIBG is typically reserved for confirming malignancy or searching for multiple/metastatic foci when anatomical imaging is inconclusive [1]. #### High-Yield Clinical Pearls for NEET-PG * **Rule of 10s:** 10% are extra-adrenal, 10% are bilateral, 10% are malignant, and 10% occur in children. * **Biochemical Screening:** The first step in diagnosis is measuring **plasma or 24-hour urinary metanephrines** (not VMA). Serum chromogranin A is also a useful tumor marker for non-secretory or metastatic disease [1]. * **Pre-operative Management:** Always start **Alpha-blockers (e.g., Phenoxybenzamine)** before Beta-blockers to avoid an unmatched alpha-adrenergic crisis. * **Genetic Associations:** MEN 2A/2B, von Hippel-Lindau (VHL), and Neurofibromatosis type 1 (NF1). Genetic testing should be considered in young patients or those with a family history [1].

Question 930: What is the most likely underlying diagnosis?

A. Cirrhosis (Correct Answer)
B. Chronic renal failure
C. Hypothyroidism
D. Myeloma

Explanation: ***Cirrhosis*** - The **classic physical signs** such as **leukonychia (white nails)** or **spider nevi** are pathognomonic features of **chronic liver disease** and cirrhosis. - These manifestations result from **decreased albumin synthesis** and **altered hormone metabolism** in advanced liver disease. *Chronic renal failure* - While CRF can cause **nail changes**, it typically presents with **half-and-half nails** (proximal white, distal pink) rather than complete leukonychia. - Associated findings include **uremic frost**, **pallor**, and **pitting edema**, which are distinct from hepatic signs. *Hypothyroidism* - Nail changes in hypothyroidism include **brittle, slow-growing nails** and **onycholysis**, not the white discoloration seen in liver disease. - Classic features include **myxedema**, **bradycardia**, and **delayed deep tendon reflexes**. *Myeloma* - **Multiple myeloma** primarily affects bones and causes **lytic lesions**, **hypercalcemia**, and **renal dysfunction**. - Nail changes are not characteristic features, and patients typically present with **bone pain** and **recurrent infections**.

Practice by Chapter

Diabetes Mellitus

Practice Questions

Thyroid Disorders

Practice Questions

Adrenal Gland Disorders

Practice Questions

Pituitary Disorders

Practice Questions

Calcium and Bone Metabolism

Practice Questions

Reproductive Endocrinology

Practice Questions

Lipid Disorders

Practice Questions

Endocrine Hypertension

Practice Questions

Multiple Endocrine Neoplasia

Practice Questions

Obesity and Metabolic Syndrome

Practice Questions

Neuroendocrine Tumors

Practice Questions

Endocrine Emergencies

Practice Questions

Want unlimited practice?

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

Start For Free