Endocrinology Practice Questions

Q: What is the most common cause of Cushing syndrome?

Steroid supplementation. **Explanation:** The most common cause of **Cushing syndrome** (the clinical state of hypercortisolism) is **Exogenous/Iatrogenic administration of glucocorticoids** [1] (Option C). This occurs in patients receiving long-term steroid therapy for conditions like asthma, rheumatoid arthritis, or autoimmune disorders [1]. **Analysis of Options:** * **Option C (Correct):** Exogenous steroid use is the overall leading cause. It leads to suppressed ACTH levels and bilateral adrenal atrophy due to negative feedback [2]. * **Option A (Incorrect):** A pituitary adenoma (Cushing **Disease**) is the most common cause of **Endogenous** Cushing syndrome (approx. 70% of endogenous cases), but it is less frequent than iatrogenic causes [4]. * **Option B (Incorrect):** Ectopic ACTH production (often from Small Cell Lung Cancer) is a rare cause of endogenous Cushing syndrome [1], typically presenting with rapid onset and severe hypokalemia. * **Option D (Incorrect):** Primary adrenal tumors (adenomas or carcinomas) are ACTH-independent endogenous causes but are less common than pituitary-driven disease [1]. **High-Yield Clinical Pearls for NEET-PG:** 1. **Cushing Syndrome vs. Disease:** "Syndrome" refers to the clinical state of high cortisol from any cause; "Disease" specifically refers to a **Pituitary Adenoma** [4]. 2. **Screening Tests:** The best initial tests are the 24-hour urinary free cortisol, late-night salivary cortisol, or the Low-Dose Dexamethasone Suppression Test (LDDST) [3]. 3. **ACTH Levels:** ACTH is **low** in iatrogenic and adrenal causes (ACTH-independent) and **high** in pituitary and ectopic causes (ACTH-dependent) [2]. 4. **Hyperpigmentation:** Seen only in ACTH-dependent causes (Pituitary/Ectopic) due to the co-secretion of Melanocyte-Stimulating Hormone (MSH).

Q: Which of the following is the leading cause of GHRH mediated acromegaly?

Carcinoid tumor. Acromegaly is most commonly caused by a GH-secreting pituitary adenoma (>95% of cases). However, in rare instances (<1%), it results from excessive Growth Hormone-Releasing Hormone (GHRH) production, which chronically stimulates the pituitary somatotrophs. **Why Carcinoid Tumor is correct:** Ectopic GHRH secretion is the most common cause of GHRH-mediated acromegaly. Among these, bronchial and gastrointestinal carcinoid tumors (along with pancreatic islet cell tumors) are the leading sources [3]. These tumors secrete GHRH into the systemic circulation, leading to somatotroph hyperplasia and subsequent GH excess. **Analysis of Incorrect Options:** * **Hypothalamic Hamartoma & Choristoma:** These are central (hypothalamic) causes of GHRH excess. While they can cause acromegaly, they are significantly rarer than peripheral ectopic sources like carcinoid tumors. * **Pluri-hormonal Adenoma:** These are pituitary tumors that secrete multiple hormones (e.g., GH and Prolactin) [1]. They cause acromegaly via direct GH secretion, not through GHRH mediation. **NEET-PG High-Yield Pearls:** * **Most common cause of Acromegaly:** Pituitary Adenoma (Somatotroph adenoma) [2]. * **Most common ectopic source of GH:** Extremely rare (e.g., pancreatic or lymphoma); most ectopic cases are actually ectopic **GHRH**. * **Biochemical Hallmark:** Failure to suppress GH levels to <1 mcg/L after an oral glucose tolerance test (OGTT) and elevated IGF-1 levels [1]. * **Imaging:** In GHRH-mediated cases, MRI may show **diffuse pituitary enlargement/hyperplasia** rather than a discrete adenoma.

Q: Hyperprolactinemia results in which of the following?

Hypogonadotropic hypogonadism. ### Explanation **Mechanism of Action (Why B is correct):** Hyperprolactinemia causes infertility and menstrual irregularities primarily by interfering with the hypothalamic-pituitary-ovarian (HPO) axis. High levels of prolactin inhibit the **pulsatile release of GnRH** (Gonadotropin-Releasing Hormone) from the hypothalamus. * Reduced GnRH leads to decreased secretion of **FSH and LH** from the anterior pituitary. * Low gonadotropins (FSH/LH) result in low estrogen levels (hypogonadism). Because the primary defect is at the level of the hypothalamus/pituitary, it is classified as **Hypogonadotropic Hypogonadism**. **Analysis of Incorrect Options:** * **A. Chronic Anovulation:** While hyperprolactinemia *causes* chronic anovulation, "Hypogonadotropic hypogonadism" is the more fundamental pathophysiological description of the hormonal state requested in this context. * **C. Androgen Insensitivity Syndrome (AIS):** This is a genetic condition (46,XY) where there is a resistance to androgens. It is unrelated to prolactin levels. * **D. Hypergonadotropic Hypogonadism:** This occurs in primary ovarian failure (e.g., Turner Syndrome, Premature Ovarian Insufficiency), where FSH/LH are elevated because the pituitary is trying to stimulate non-functional ovaries. **NEET-PG High-Yield Pearls:** * **Clinical Presentation:** The classic triad is **Amenorrhea, Galactorrhea, and Infertility**. * **Drug-Induced:** The most common pharmacological cause is **Antipsychotics** (due to Dopamine antagonism). * **Hook Effect:** In cases of giant adenomas, extremely high prolactin can paradoxically show a low lab value; serial dilution is required for diagnosis. * **Treatment:** Medical management with **Dopamine agonists** (Cabergoline > Bromocriptine) is the first-line treatment, even for large macroprolactinomas. Surgery is reserved for refractory cases.

Q: Hypercalcemia is not seen in which of the following conditions?

Vitamin A deficiency. The correct answer is **Vitamin A deficiency**. In fact, it is **Vitamin A toxicity (Hypervitaminosis A)** that causes hypercalcemia. High levels of Vitamin A stimulate osteoclast activity, leading to increased bone resorption and elevated serum calcium levels. **Analysis of Options:** * **Lithium therapy:** Lithium is a well-known cause of hypercalcemia [1]. It shifts the set-point of the calcium-sensing receptor (CaSR) in the parathyroid glands, requiring higher calcium levels to suppress Parathyroid Hormone (PTH) secretion. This results in **Hyperparathyroidism**. * **Chronic Renal Failure (CRF):** While early-stage CRF typically presents with hypocalcemia [2], long-standing disease leads to **Tertiary Hyperparathyroidism** [1]. In this state, the parathyroid glands become autonomous due to chronic overstimulation, leading to hypercalcemia. * **Multiple Myeloma:** This is a classic cause of hypercalcemia [1]. Myeloma cells produce Osteoclast Activating Factors (OAFs) like IL-6 and RANK-ligand, which cause extensive lytic bone lesions and release calcium into the bloodstream. **High-Yield Clinical Pearls for NEET-PG:** 1. **Vitamin D vs. Vitamin A:** Both cause hypercalcemia in toxicity, but via different mechanisms (Vitamin D increases intestinal absorption; Vitamin A increases bone resorption). 2. **Milk-Alkali Syndrome:** A triad of hypercalcemia, metabolic alkalosis, and renal failure due to excessive ingestion of calcium and absorbable antacids [1]. 3. **Thiazide Diuretics:** These cause hypercalcemia (by increasing renal calcium reabsorption) [1], whereas **Loop diuretics** (Furosemide) are used to treat it (by increasing calcium excretion). 4. **Granulomatous Diseases:** (e.g., Sarcoidosis, TB) cause hypercalcemia due to ectopic production of 1,25-dihydroxyvitamin D by macrophages [1].

Q: Which of the following conditions is not associated with diabetes mellitus?

Hypothyroidism. ### Explanation The correct answer is **Hypothyroidism**. Diabetes mellitus (DM) is frequently associated with conditions that cause an excess of **counter-regulatory hormones** [1]. These hormones (cortisol, growth hormone, catecholamines, and glucagon) oppose the action of insulin, leading to increased gluconeogenesis and insulin resistance [3]. **1. Why Hypothyroidism is the correct answer:** Hypothyroidism is generally associated with a **decreased** rate of glucose absorption from the gut and a slower rate of insulin degradation. Unlike the other options, it does not cause hyperglycemia. In fact, in patients with pre-existing diabetes, the development of hypothyroidism may actually reduce insulin requirements and increase the risk of hypoglycemia. **2. Why the other options are incorrect:** * **Cushing Syndrome:** Characterized by excess **Cortisol**, which increases hepatic gluconeogenesis and decreases peripheral glucose uptake, leading to "Steroid Diabetes" [1], [3]. * **Acromegaly:** Characterized by excess **Growth Hormone (GH)**. GH is a potent insulin antagonist that promotes lipolysis and inhibits glucose utilization in muscles [1], [2]. * **Pheochromocytoma:** Characterized by excess **Catecholamines** (Epinephrine/Norepinephrine). These stimulate glycogenolysis and inhibit insulin secretion from pancreatic beta cells via alpha-2 adrenergic receptors [3], [4]. **Clinical Pearls for NEET-PG:** * **Secondary Diabetes:** This term refers to DM caused by other endocrine disorders (as listed above) or pancreatic diseases (e.g., Chronic Pancreatitis) [1]. * **Hyperthyroidism vs. Hypothyroidism:** While hypothyroidism doesn't cause DM, **Hyperthyroidism** can worsen glycemic control by increasing glucose absorption and promoting glycogenolysis [4]. * **Glucagonoma:** Another high-yield association; it presents with the "4Ds": Diabetes, Dermatitis (Necrolytic Migratory Erythema), Depression, and DVT.

Q: Which statement is true regarding Familial Hypocalciuric Hypercalcemia?

Treatment is rarely necessary.. **Explanation:** **Familial Hypocalciuric Hypercalcemia (FHH)** is a benign genetic disorder characterized by lifelong, stable elevations in serum calcium levels. 1. **Why Option D is correct:** In FHH, the body "resets" its calcium thermostat to a higher level. Despite the hypercalcemia, patients are typically **asymptomatic**, and the condition does not lead to the complications seen in primary hyperparathyroidism (like kidney stones or bone loss). Therefore, surgical or medical intervention is **rarely necessary**, and the primary goal is to avoid unnecessary parathyroidectomy. 2. **Why other options are incorrect:** * **Option A:** FHH is inherited in an **Autosomal Dominant** pattern. * **Option B:** The defect is in the **Calcium-Sensing Receptor (CaSR)**, not the PTH receptor [1]. This inactivating mutation makes the parathyroid glands and kidneys less sensitive to calcium, requiring higher levels to suppress PTH and promote urinary calcium excretion. * **Option C:** Hypercalcemia in FHH is present from **birth**. While it is often detected incidentally later in life, the biochemical abnormality is lifelong, unlike primary hyperparathyroidism which usually develops later [1]. **High-Yield Clinical Pearls for NEET-PG:** * **The "Low" Rule:** FHH is characterized by **Low** urinary calcium excretion (Urinary Calcium:Creatinine Clearance Ratio ** 0.02**. * **Key takeaway:** If a patient has high calcium, low urine calcium, and a family history of hypercalcaemia—**do not operate.**

Q: Gynecomastia is seen in which of the following conditions?

Klinefelter's syndrome. **Explanation:** **Klinefelter’s Syndrome (47, XXY)** is the most common genetic cause of male hypogonadism [2] and a classic cause of gynecomastia. The underlying mechanism involves **primary testicular failure**, where fibrotic changes in the seminiferous tubules lead to low testosterone levels [1]. This triggers a compensatory rise in LH (Luteinizing Hormone), which stimulates Leydig cells to increase the aromatization of testosterone into estradiol [3]. The resulting **decreased testosterone-to-estrogen ratio** leads to the development of breast tissue in approximately 50–80% of patients [1]. **Analysis of Incorrect Options:** * **Secondary Syphilis:** Typically presents with a generalized maculopapular rash (including palms and soles), lymphadenopathy, and condyloma lata. It does not involve the endocrine pathways leading to breast tissue proliferation. * **Tuberculoid Leprosy:** Characterized by hypopigmented, anesthetic skin patches and peripheral nerve enlargement. While **Lepromatous leprosy** can cause gynecomastia (due to orchitis and testicular atrophy), the Tuberculoid form generally does not affect the testes. * **HIV:** While certain antiretroviral therapies (ART) or associated lipodystrophy can mimic breast enlargement, HIV itself is not a primary cause of glandular gynecomastia. **High-Yield Clinical Pearls for NEET-PG:** * **Risk of Malignancy:** Patients with Klinefelter’s have a **20–50 times higher risk** of developing male breast cancer compared to the general population [4]. * **Hormonal Profile:** Characterized by **High FSH/LH** and **Low Testosterone** (Hypergonadotropic Hypogonadism) [1]. * **Clinical Triad:** Small firm testes, gynecomastia, and azoospermia (infertility) [1]. * **Drug-induced Gynecomastia (Mnemonic: DISCO):** Digoxin, Isoniazid, Spironolactone, Cimetidine, Estrogens/Ketoconazole [3].

Q: A 76-year-old woman presents with a 1-month history of involuntary weight loss, anxiety, and palpitations. She has no prior history of anxiety or palpitations. Her only medical history is hypertension managed with losartan. On examination, her blood pressure is 120/70 mm Hg, heart rate is 100/min and regular. Auscultation reveals normal heart sounds and clear lungs. Physical findings include a thyroid goiter, warm skin, and a fine tremor in her hands. What is the most likely cardiac finding?

Paroxysmal atrial fibrillation. **Explanation:** The clinical presentation of weight loss, anxiety, tremors, and a goiter in an elderly patient is highly suggestive of **Hyperthyroidism** (likely Toxic Multinodular Goiter given the age) [1]. **1. Why Option C is Correct:** Hyperthyroidism induces a hyperdynamic state by increasing the expression of beta-adrenergic receptors and affecting cardiac myocytes directly. In elderly patients, "Apathetic Hyperthyroidism" often presents with cardiac manifestations rather than classic sympathetic symptoms [2]. **Atrial Fibrillation (AF)** is the most common arrhythmia associated with thyrotoxicosis, occurring in 10–15% of patients, particularly those over age 60 [1]. It often starts as paroxysmal AF before becoming persistent. **2. Why Incorrect Options are Wrong:** * **A. Prolonged circulation time:** In hyperthyroidism, the circulation time is actually **shortened** due to increased heart rate and stroke volume (hyperdynamic circulation). Prolonged circulation time is a feature of hypothyroidism or congestive heart failure. * **B. Decreased cardiac output:** Hyperthyroidism causes **increased cardiac output** to meet the high metabolic demands of peripheral tissues. * **D. Pericardial effusion:** This is a classic finding in **Hypothyroidism** (Myxedema), where increased capillary permeability and reduced lymphatic drainage lead to fluid accumulation. **NEET-PG High-Yield Pearls:** * **Most common arrhythmia in Thyrotoxicosis:** Sinus tachycardia [1]. * **Most common "significant" arrhythmia in elderly thyrotoxic patients:** Atrial Fibrillation [2]. * **Thyroid Storm Management:** Propranolol is used not just for tachycardia, but to inhibit the peripheral conversion of T4 to T3 [2]. * **Apathetic Hyperthyroidism:** Always suspect this in an elderly patient with new-onset AF or unexplained weight loss, even if they lack "classic" signs like exophthalmos [3].

Question 1

A 19-year-old man and one of his two brothers have had polyuria and polydipsia since birth. His sisters and parents are unaffected. What is the most likely diagnosis for this patient presenting with polyuria and polydipsia?

Accepted Answer

Nephrogenic DI

Answer

Central diabetes insipidus (DI)

Answer

Primary polydipsia

Answer

Osmotic diuresis

Question 2

What is the most common cause of Cushing syndrome?

Accepted Answer

Steroid supplementation

Answer

Pituitary tumor

Answer

Ectopic ACTH producing tumor

Answer

Adrenal tumor

Question 3

Which of the following is a complication of diabetes mellitus?

Accepted Answer

Cataract

Answer

Rubeosis iridis

Answer

Retinal detachment

Answer

Cranial nerve palsy

Question 4

Which of the following is the leading cause of GHRH mediated acromegaly?

Accepted Answer

Carcinoid tumor

Answer

Hypothalamic Hamartoma

Answer

Choristoma

Answer

Pluri-hormonal adenoma

Question 5

Hyperprolactinemia results in which of the following?

Accepted Answer

Hypogonadotropic hypogonadism

Answer

Chronic anovulation

Answer

Androgen insensitivity syndrome

Answer

Hypergonadotropic hypogonadism

Question 6

Hypercalcemia is not seen in which of the following conditions?

Accepted Answer

Vitamin A deficiency

Answer

Lithium therapy

Answer

Chronic renal failure

Answer

Multiple myeloma

Question 7

Which of the following conditions is not associated with diabetes mellitus?

Accepted Answer

Hypothyroidism

Answer

Cushing syndrome

Answer

Acromegaly

Answer

Pheochromocytoma

Question 8

Which statement is true regarding Familial Hypocalciuric Hypercalcemia?

Accepted Answer

Treatment is rarely necessary.

Answer

It is inherited in an autosomal recessive pattern.

Answer

The cause is a defect in the PTH receptor.

Answer

Clinical symptoms typically manifest in the third decade of life.

Question 9

Gynecomastia is seen in which of the following conditions?

Accepted Answer

Klinefelter's syndrome

Answer

Secondary syphilis

Answer

Tuberculoid leprosy

Answer

HIV

Question 10

A 76-year-old woman presents with a 1-month history of involuntary weight loss, anxiety, and palpitations. She has no prior history of anxiety or palpitations. Her only medical history is hypertension managed with losartan. On examination, her blood pressure is 120/70 mm Hg, heart rate is 100/min and regular. Auscultation reveals normal heart sounds and clear lungs. Physical findings include a thyroid goiter, warm skin, and a fine tremor in her hands. What is the most likely cardiac finding?

Accepted Answer

Paroxysmal atrial fibrillation

Answer

Prolonged circulation time

Answer

Decreased cardiac output

Answer

Pericardial effusion

Endocrinology — MCQs

Endocrinology — MCQs

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