Endocrinology Practice Questions

Q: How many major hormones are produced by the anterior pituitary gland?

6. **Explanation:** The anterior pituitary gland (adenohypophysis) is responsible for the synthesis and secretion of **six major peptide hormones** [3]. These are produced by five distinct cell types and are regulated by hypothalamic releasing or inhibiting factors [1]. The six major hormones are: 1. **Growth Hormone (GH):** Produced by Somatotrophs [1]. 2. **Prolactin (PRL):** Produced by Lactotrophs [1]. 3. **Adrenocorticotropic Hormone (ACTH):** Produced by Corticotrophs [1]. 4. **Thyroid-Stimulating Hormone (TSH):** Produced by Thyrotrophs [1]. 5. **Follicle-Stimulating Hormone (FSH):** Produced by Gonadotrophs [1]. 6. **Luteinizing Hormone (LH):** Produced by Gonadotrophs [1]. **Analysis of Options:** * **Option A (4) & B (5):** These are incorrect as they omit essential trophic hormones (like the gonadotropins or prolactin) that are vital for systemic endocrine function. * **Option D (7):** This is a common point of confusion. While the intermediate lobe (pars intermedia) produces **Melanocyte-Stimulating Hormone (MSH)**, in adult humans, this lobe is vestigial, and MSH is not considered one of the "major" anterior pituitary hormones [2]. **High-Yield NEET-PG Clinical Pearls:** * **Cell Populations:** Somatotrophs are the most numerous cells (50%), followed by Lactotrophs (15-25%) [1]. * **Staining Characteristics:** GH and Prolactin are secreted by **Acidophils**, while TSH, ACTH, FSH, and LH are secreted by **Basophils** (Mnemonic: *B-FLAT* for Basophils). * **Posterior Pituitary:** Remember that the posterior pituitary (neurohypophysis) produces **zero** hormones; it only stores and releases Oxytocin and ADH, which are synthesized in the hypothalamus [2]. * **Prolactin Regulation:** It is the only anterior pituitary hormone under predominant **inhibitory** control (by Dopamine).

Q: Which of the following are cardiopulmonary manifestations of hyperthyroidism?

Cardiomegaly. **Explanation:** Hyperthyroidism induces a hyperdynamic circulatory state due to the direct effects of thyroid hormones on the myocardium and the potentiation of the sympathetic nervous system [1]. **Why Cardiomegaly is Correct:** In hyperthyroidism, there is a significant increase in stroke volume and heart rate to meet increased metabolic demands [1]. This leads to a chronic increase in cardiac output. Over time, the heart undergoes **compensatory hypertrophy and chamber dilatation**, resulting in **cardiomegaly**. This is often visible on a chest X-ray and is a classic manifestation of long-standing thyrotoxicosis. **Analysis of Incorrect Options:** * **A. Tachycardia:** While tachycardia is the *most common* cardiovascular sign of hyperthyroidism [2], it is a **symptom/sign**, whereas the question specifically points toward structural or pathological manifestations like cardiomegaly in this context. (Note: In many MCQ formats, if "All of the above" isn't an option, structural changes like cardiomegaly are prioritized as definitive manifestations). * **B. Sinus Bradycardia:** This is a feature of **hypothyroidism**. Hyperthyroidism characteristically causes sinus tachycardia or atrial fibrillation [2]. * **C. Low Output Cardiac Failure:** Hyperthyroidism causes **High-Output Heart Failure**. The systemic vascular resistance is low, and cardiac output is elevated, but the heart eventually fails to meet the excessive metabolic demands [3]. Low output failure is typical of primary cardiomyopathies or valvular diseases. **NEET-PG High-Yield Pearls:** * **Atrial Fibrillation:** The most common arrhythmia in elderly patients with thyrotoxicosis (approx. 10-15%) [2]. * **Pulse Pressure:** Characteristically **widened** due to increased systolic BP and decreased diastolic BP (peripheral vasodilation) [1]. * **Treatment:** Beta-blockers (Propranolol) are the first-line symptomatic treatment to control adrenergic symptoms [3].

Q: What is the most common cause of ectopic ACTH production?

Small cell carcinoma of the lung. ### Explanation **Correct Answer: C. Small cell carcinoma of the lung** **Why it is correct:** Ectopic ACTH syndrome occurs when a non-pituitary tumor secretes adrenocorticotropic hormone, leading to ACTH-dependent Cushing syndrome [1]. **Small cell carcinoma of the lung (SCLC)** is the most common cause, accounting for approximately 50% of all ectopic ACTH cases [2]. In SCLC, the tumor cells (neuroendocrine in origin) bypass the normal regulatory feedback loop, leading to massive cortisol production. Patients often present with rapid-onset hypertension, profound hypokalemia, and hyperpigmentation rather than the classic "cushingoid" features (like buffalo hump) due to the aggressive nature of the underlying malignancy. **Why the other options are incorrect:** * **A & B (RCC and HCC):** While these tumors are known for various paraneoplastic syndromes (e.g., Erythropoietin production in RCC), they are extremely rare causes of ectopic ACTH [2]. * **D (Pheochromocytoma):** This is a neuroendocrine tumor that can occasionally secrete ACTH, but it is significantly less common than SCLC. **NEET-PG High-Yield Pearls:** 1. **Most common cause of Cushing Syndrome overall:** Exogenous steroid use. 2. **Most common endogenous cause:** Cushing Disease (Pituitary adenoma). 3. **Screening Test:** 24-hour urinary free cortisol or Low-Dose Dexamethasone Suppression Test (LDDST). 4. **Differentiation:** High-Dose Dexamethasone Suppression Test (HDDST) suppresses cortisol in Cushing Disease but **fails** to suppress it in Ectopic ACTH production. 5. **Other Ectopic Sources:** Bronchial carcinoid (second most common), thymic tumors, and pancreatic islet cell tumors.

Q: Pheochromocytoma may be associated with which of the following?

Medullary carcinoma of the thyroid. ### Explanation **1. Why Medullary Carcinoma of the Thyroid (MTC) is Correct:** Pheochromocytoma is a key component of **Multiple Endocrine Neoplasia (MEN) Type 2 syndromes**, which are inherited in an autosomal dominant fashion due to mutations in the **RET proto-oncogene**. * **MEN 2A (Sipple Syndrome):** Characterized by Medullary Thyroid Carcinoma (100%), Pheochromocytoma (50%), and Parathyroid Hyperplasia (20%). * **MEN 2B:** Characterized by Medullary Thyroid Carcinoma, Pheochromocytoma, and mucosal neuromas/marfanoid habitus. In both syndromes, MTC is the most common manifestation, arising from the parafollicular C-cells that secrete calcitonin. **2. Why the Other Options are Incorrect:** * **Options B, C, and D:** Papillary, Follicular, and Anaplastic carcinomas are all derived from **thyroid follicular cells**. These are considered "sporadic" or related to radiation/iodine deficiency and are **not** associated with the RET mutations found in MEN syndromes. While Papillary carcinoma is the most common thyroid cancer overall, it has no syndromic link to Pheochromocytoma. **3. High-Yield Clinical Pearls for NEET-PG:** * **Rule of 10s for Pheochromocytoma:** 10% bilateral, 10% malignant, 10% extra-adrenal (Paraganglioma), and 10% familial (though modern genetics suggest up to 30-40% are familial). * **Surgical Sequence:** In a patient with both MTC and Pheochromocytoma, **always resect the Pheochromocytoma first** to prevent a lethal hypertensive crisis during thyroid surgery. * **Screening:** Patients with MTC should be screened for RET mutations and urinary catecholamines/metanephrines. * **Biomarker:** Calcitonin is the tumor marker for MTC.

Q: Anterior scalloping of vertebrae is seen in which of the following conditions?

Aortic aneurysm. Vertebral scalloping refers to an exaggerated concavity of the vertebral body. **Anterior scalloping** is a classic radiological sign of a long-standing **Abdominal Aortic Aneurysm (AAA)** [1]. The mechanism is "pressure erosion": the constant, rhythmic pulsations of the aneurysmal sac against the adjacent vertebral bodies lead to bone resorption. Interestingly, the intervertebral discs remain relatively preserved because fibrocartilage is more resistant to pressure erosion than bone.

Q: Which of the following statements about Cushing's syndrome is true?

ACTH secretion is the commonest cause.. Cushing’s syndrome refers to the clinical state of chronic glucocorticoid excess. The most common cause of **endogenous** Cushing’s syndrome is **ACTH-dependent** disease (approx. 80%), specifically a pituitary adenoma (Cushing’s Disease). [1] When considering all causes, including exogenous sources, iatrogenic administration of glucocorticoids is the overall most common cause. [1] However, among the pathological endogenous options provided, ACTH hypersecretion (primarily pituitary) is the leading etiology. [4] **2. Why the Other Options are Incorrect:** * **Option A:** In Cushing’s syndrome, the normal negative feedback loop is disrupted. Therefore, **low-dose** (1 mg or 2 mg) dexamethasone **fails to suppress** cortisol secretion. [3] Suppression with low-dose dexamethasone is the normal physiological response used to rule out the syndrome. * **Option B:** Adrenal **adenomas** are significantly more common than adrenal carcinomas. Adrenal carcinomas are rare, though they often present with more severe, rapid-onset virilization and hypercortisolism. [1] * **Option C:** In Cushing’s Disease (pituitary cause), the majority of cases (>90%) are caused by **microadenomas**, which are typically **less than 1 cm** (often 1 cm) are rare in this context. **Clinical Pearls for NEET-PG:** * **Screening Tests:** 24-hour urinary free cortisol, Late-night salivary cortisol, or Low-dose dexamethasone suppression test (LDDST). [3] * **High-dose Dexamethasone Test (HDDST):** Used to differentiate Pituitary (suppresses by >50%) from Ectopic ACTH (does not suppress). [2] * **Hyperpigmentation:** Seen only in ACTH-dependent causes (Pituitary or Ectopic) due to the co-secretion of Melanocyte-Stimulating Hormone (MSH). * **Hypokalemic Metabolic Alkalosis:** Highly suggestive of **Ectopic ACTH** secretion (e.g., Small Cell Lung Cancer).

Question 1

A 28-year-old woman with diabetes presents with painless lesions on her leg, characterized by a central depression and raised irregular margins. What is the most likely diagnosis?

Accepted Answer

Necrobiosis lipoidica diabeticorum

Answer

Eruptive xanthomas

Answer

Gangrene

Answer

Staphylococcal infection

Question 2

How many major hormones are produced by the anterior pituitary gland?

Accepted Answer

6

Answer

4

Answer

5

Answer

7

Question 3

Which of the following are cardiopulmonary manifestations of hyperthyroidism?

Accepted Answer

Cardiomegaly

Answer

Tachycardia

Answer

Sinus bradycardia

Answer

Low output cardiac failure

Question 4

What is the most common cause of ectopic ACTH production?

Accepted Answer

Small cell carcinoma of the lung

Answer

Renal cell carcinoma

Answer

Hepatocellular carcinoma

Answer

Pheochromocytoma

Question 5

Which complication of diabetes mellitus cannot be prevented by strict control of blood sugar levels?

Accepted Answer

Macular edema

Answer

Amyotrophy

Answer

Nerve conductivity

Answer

Microalbuminuria

Question 6

Pheochromocytoma may be associated with which of the following?

Accepted Answer

Medullary carcinoma of the thyroid

Answer

Papillary carcinoma of the thyroid

Answer

Anaplastic carcinoma of the thyroid

Answer

Follicular carcinoma of the thyroid

Question 7

Anterior scalloping of vertebrae is seen in which of the following conditions?

Accepted Answer

Aortic aneurysm

Answer

Osteogenesis imperfecta

Answer

Metastasis

Answer

Renal cell carcinoma

Question 8

A 28-year-old lady has gained 10 kg over 3 years and presents with oligomenorrhea followed by amenorrhea for 8 months. Her blood pressure is 160/100 mm Hg. Which of the following is the most appropriate investigation?

Accepted Answer

Plasma cortisol

Answer

Serum electrolytes

Answer

Plasma testosterone and ultrasound evaluation of pelvis

Answer

T3, T4 and TSH

Question 9

What is true about Type 1 diabetes mellitus?

Accepted Answer

Increased lipolysis

Answer

Decreased hepatic glucose output

Answer

Increased glucose uptake

Answer

Decreased protein catabolism

Question 10

Which of the following statements about Cushing's syndrome is true?

Accepted Answer

ACTH secretion is the commonest cause.

Answer

Low-dose dexamethasone suppresses cortisol secretion.

Answer

Carcinoma of the adrenal gland is more common than adenoma.

Answer

Pituitary adenoma size is usually greater than 2 cm.

Endocrinology — MCQs

Endocrinology — MCQs

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