Endocrinology — MCQs

A 16-year-old girl presents with a one-month history of visual disturbances, including difficulty seeing people unless they are directly in front of her and walking into doors. Her menstrual cycles have become irregular and have ceased in the past few months. Physical examination reveals bilateral temporal visual field deficits with normal nasal visual fields. A mass is identified inferior to the hypothalamus on cranial imaging. Which hormone do the cells within this mass most likely produce?

Q353Easy

Which of the following conditions might cause endocrine shock?

Q354Easy

Which of the following is NOT a feature of hypocalcemia?

Q355Medium

What is the most common differential diagnosis of hyperthyroidism in a young female?

Q356Easy

What is the effect of calcitonin on bone resorption?

Q357Easy

Which of the following is NOT a feature of primary hyperaldosteronism?

Q358Medium

An 83-year-old man with poor nutrition presents with easy bruising and bleeding gums. On examination, he has inflamed bleeding gums, multiple areas of ecchymoses, and perifollicular hemorrhages. His coagulation profile and liver function tests are normal. What is the most likely diagnosis for this patient's vitamin deficiency or excess?

Q359Medium

A 60-year-old woman presents with concerns about osteoporosis due to her mother's recent hip fracture. She has a 50-pack-year smoking history, started hormone replacement therapy for 6 years after menopause at age 49, and has a BMI of 26.7 kg/m². She takes a multivitamin and levothyroxine 50 mg/d. Her exercise includes lawn mowing and gardening. What is the most appropriate recommendation for osteoporosis screening for this patient?

Q360Medium

Gynaecomastia may be seen in all of the following conditions except?

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 351: Which of the following findings is indicative of diabetes mellitus?

A. HbA1C of 6.5%
B. Random blood sugar of 205 mg/dL with polyuria (Correct Answer)
C. Blood sugar of 140 mg/dL after 6 hours of fasting
D. Glucose of 190 mg/dL after 2 hours of eating red meat

Explanation: The diagnosis of Diabetes Mellitus (DM) is based on specific glycemic thresholds established by the ADA and WHO [1]. **Explanation of the Correct Option:** **Option B** is correct because a **Random Blood Sugar (RBS) ≥ 200 mg/dL** in the presence of **classic symptoms** of hyperglycemia (polyuria, polydipsia, or unexplained weight loss) is a definitive diagnostic criterion for DM [1]. A single random value without symptoms is generally insufficient and requires a repeat test. **Analysis of Incorrect Options:** * **Option A:** An **HbA1C ≥ 6.5%** is indeed diagnostic. However, in the context of standardized exams, if two options are technically correct, the one including clinical symptoms (Option B) is often prioritized as the "most" indicative clinical presentation. *Note: In some versions of this question, Option A might be considered correct, but Option B is the classic clinical definition.* * **Option C:** Impaired Fasting Glucose (IFG) is defined as a fasting plasma glucose (FPG) of 100–125 mg/dL. A value of **≥ 126 mg/dL** after an **8-hour fast** is required for a DM diagnosis [1]. 6 hours is insufficient for a true "fasting" state. * **Option D:** The 2-hour post-prandial (2-hr PP) or Oral Glucose Tolerance Test (OGTT) threshold for DM is **≥ 200 mg/dL**. Furthermore, this test must be performed using a **75g anhydrous glucose load**, not a protein-heavy meal like red meat, which does not standardize the glycemic response. **High-Yield NEET-PG Pearls:** * **Diagnostic Criteria for DM:** 1. FPG ≥ 126 mg/dL (8-hr fast) [1]. 2. 2-hr OGTT ≥ 200 mg/dL. 3. HbA1C ≥ 6.5%. 4. RBS ≥ 200 mg/dL + Symptoms [1]. * **Prediabetes:** HbA1C 5.7–6.4%; FPG 100–125 mg/dL; 2-hr OGTT 140–199 mg/dL [1]. * **Gold Standard for Gestational DM:** OGTT (Carpenter-Coustan criteria or DIPSI).

Question 352: A 16-year-old girl presents with a one-month history of visual disturbances, including difficulty seeing people unless they are directly in front of her and walking into doors. Her menstrual cycles have become irregular and have ceased in the past few months. Physical examination reveals bilateral temporal visual field deficits with normal nasal visual fields. A mass is identified inferior to the hypothalamus on cranial imaging. Which hormone do the cells within this mass most likely produce?

A. Oxytocin
B. Somatostatin
C. Thyrotropin-releasing hormone
D. Thyroid-stimulating hormone (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Thyroid-stimulating hormone (TSH)** **Clinical Reasoning:** The patient presents with a classic triad: **bitemporal hemianopia** (due to compression of the optic chiasm), **secondary amenorrhea**, and a **sellar/suprasellar mass**. The optic chiasm sits directly above the pituitary gland; a mass arising from the pituitary (inferior to the hypothalamus) compresses the decussating nasal retinal fibers, causing loss of the temporal visual fields. The most common local complication of a large pituitary tumor is compression of the optic pathway [1]. Among the options provided, **Thyroid-stimulating hormone (TSH)** is the only hormone produced by the **anterior pituitary gland** (adenohypophysis). Pituitary adenomas (e.g., thyrotropinomas, prolactinomas, or somatotropinomas) are the most common cause of such clinical presentations in the sellar region [1]. **Analysis of Incorrect Options:** * **A. Oxytocin:** Produced by the paraventricular and supraoptic nuclei of the **hypothalamus** and stored/released by the posterior pituitary. It is not produced by cells within a pituitary mass. * **B. Somatostatin:** A regulatory hormone produced by the **hypothalamus** (and delta cells of the pancreas) that inhibits growth hormone release. * **C. Thyrotropin-releasing hormone (TRH):** Produced by the **hypothalamus** to stimulate the anterior pituitary [1]. It is not a product of pituitary cells. **NEET-PG High-Yield Pearls:** * **Visual Deficit:** Bitemporal hemianopia is the hallmark of optic chiasm compression. If the lesion is superior to the chiasm (e.g., Craniopharyngioma), it typically affects the **inferior** quadrants first. If inferior (e.g., Pituitary Adenoma), it affects the **superior** quadrants first. * **Hormone Localization:** Remember the mnemonic **"FLAT PiG"** for anterior pituitary hormones: **F**SH, **L**H, **A**CTH, **T**SH, **P**rolactin, and **G**H. * **Amenorrhea in Pituitary Masses:** This can occur due to a functional adenoma (e.g., Prolactinoma) or "stalk effect," where compression of the pituitary stalk prevents dopamine (prolactin-inhibiting factor) from reaching the gland, leading to hyperprolactinemia.

Question 353: Which of the following conditions might cause endocrine shock?

A. Hypothyroidism
B. Hyperthyroidism
C. Adrenal insufficiency
D. All of the above (Correct Answer)

Explanation: **Explanation:** Endocrine shock refers to circulatory collapse caused by severe hormonal imbalances. The correct answer is **All of the above** because critical dysfunction in the thyroid or adrenal glands can lead to profound hemodynamic instability. 1. **Adrenal Insufficiency (Addisonian Crisis):** This is the most common cause of endocrine shock. A deficiency in cortisol and aldosterone leads to severe peripheral vasodilation, decreased cardiac contractility, and hypovolemia (due to sodium and water loss) [1]. This results in distributive and hypovolemic shock that is often refractory to vasopressors until corticosteroids are administered. 2. **Hypothyroidism (Myxedema Coma):** Severe hypothyroidism causes shock through multiple mechanisms: bradycardia, decreased myocardial contractility (reduced cardiac output), and increased systemic vascular resistance [1]. It can also lead to pericardial effusion and associated adrenal insufficiency [1]. 3. **Hyperthyroidism (Thyroid Storm):** While hyperthyroidism typically causes a high-output state, a "Thyroid Storm" can lead to high-output heart failure, tachyarrhythmias, and profound dehydration, eventually resulting in cardiovascular collapse and shock [1]. **Clinical Pearls for NEET-PG:** * **Waterhouse-Friderichsen Syndrome:** Adrenal shock caused by hemorrhagic necrosis of the adrenal glands, typically secondary to *Neisseria meningitidis* sepsis. * **Refractory Shock:** Always suspect adrenal insufficiency in a patient with shock that does not respond to fluids or inotropes [1]. * **Treatment Priority:** In suspected adrenal crisis, do not wait for laboratory confirmation; administer IV Hydrocortisone (100mg stat) immediately. * **Myxedema Coma Triad:** Hypothermia, Bradycardia, and Altered Mental Status.

Question 354: Which of the following is NOT a feature of hypocalcemia?

A. Numbness and tingling
B. Circumoral paresthesia
C. Depressed tendon reflexes (Correct Answer)
D. Skin irritability and sensitivity

Explanation: The correct answer is **C. Depressed tendon reflexes**. **1. Underlying Medical Concept:** Hypocalcemia increases neuromuscular excitability. Calcium ions normally stabilize the neuronal membrane by blocking sodium channels. When extracellular calcium levels are low, the threshold for depolarization decreases, making neurons **hyperexcitable**. This leads to spontaneous firing of motor and sensory nerves. Consequently, hypocalcemia is characterized by **hyperreflexia** (brisk tendon reflexes), tetany, and muscle spasms. Depressed or absent reflexes are typically seen in **hypercalcemia** or hypermagnesemia, where the membrane is over-stabilized. **2. Analysis of Incorrect Options:** * **A & B (Numbness, tingling, and circumoral paresthesia):** These are the earliest sensory manifestations of hypocalcemia. The hyperexcitability of sensory nerve fibers manifests as "pins and needles" sensations, particularly around the mouth (circumoral) and in the fingertips. * **D (Skin irritability and sensitivity):** Chronic hypocalcemia affects ectodermal tissues, leading to dry, scaly skin, brittle nails, and dermatological sensitivity. Neuromuscular irritability also manifests as "irritability" in the clinical sense (agitation or seizures). **3. High-Yield Clinical Pearls for NEET-PG:** * **Chvostek’s Sign:** Tapping the facial nerve leads to twitching of facial muscles. * **Trousseau’s Sign:** Carpopedal spasm induced by inflating a BP cuff above systolic pressure for 3 minutes (more specific than Chvostek’s). * **ECG Finding:** The classic hallmark is **prolonged QT interval** (due to lengthening of the ST segment) [1]. * **Etiology:** Most common cause is post-thyroidectomy (accidental parathyroid removal) [1] or Vitamin D deficiency [1].

Question 355: What is the most common differential diagnosis of hyperthyroidism in a young female?

A. Hysteria
B. Essential tremor
C. Anxiety neurosis (Correct Answer)
D. Parkinsonism

Explanation: ### Explanation **Correct Answer: C. Anxiety neurosis** **Why Anxiety neurosis is the correct answer:** Hyperthyroidism and anxiety neurosis share a significant overlap in clinical presentation, particularly in young females [2]. Both conditions present with **tachycardia, palpitations, excessive sweating, irritability, and fine tremors** [1], [2]. Because these symptoms are non-specific, many patients with early or mild hyperthyroidism are initially misdiagnosed as having an anxiety disorder or "panic attacks." The primary clinical differentiator is that in hyperthyroidism, tachycardia persists during sleep, and there is often unexplained weight loss despite a normal or increased appetite. **Analysis of Incorrect Options:** * **A. Hysteria:** This is an outdated psychiatric term (now categorized under Conversion or Dissociative disorders). While it may involve emotional outbursts, it does not typically mimic the sustained sympathomimetic symptoms (like heat intolerance and weight loss) seen in hyperthyroidism. * **B. Essential tremor:** While this involves a fine tremor, it is usually an isolated symptom (postural or kinetic) and lacks the systemic features of hyperthyroidism like tachycardia, goiter, or eye signs. * **D. Parkinsonism:** This presents with a "pill-rolling" **resting tremor**, bradykinesia, and rigidity. It is primarily a disease of the elderly, making it an unlikely differential for a young female with the hyperkinetic features of thyrotoxicosis. **High-Yield Clinical Pearls for NEET-PG:** * **The "Sleeping Pulse" Test:** A key bedside differentiator; tachycardia in anxiety usually resolves during sleep, whereas in hyperthyroidism, the heart rate remains elevated. * **Tremor Characteristics:** Hyperthyroidism causes a **fine, rapid, peripheral tremor** [2] (best seen by placing a sheet of paper on outstretched hands). * **Most Common Cause:** Graves' disease is the most common cause of hyperthyroidism in young females [2], [3]. * **Initial Screening:** The most sensitive initial test for hyperthyroidism is a **Serum TSH level** (which will be suppressed) [1], [2].

Question 356: What is the effect of calcitonin on bone resorption?

A. Inhibits resorption (Correct Answer)
B. Promotes resorption
C. Has both properties
D. Enhances mineralization

Explanation: Calcitonin is a 32-amino acid peptide hormone secreted by the **parafollicular cells (C-cells) of the thyroid gland**. Its primary physiological role is to lower plasma calcium levels, acting as a functional antagonist to Parathyroid Hormone (PTH). [1] **Why Option A is correct:** Calcitonin directly **inhibits bone resorption** by acting on specific receptors located on **osteoclasts**. [1] Upon binding, it causes the osteoclasts to lose their "ruffled borders" and shrink, effectively decreasing their resorptive activity. This leads to a reduction in the release of calcium and phosphate from the bone matrix into the blood. [1] **Why the other options are incorrect:** * **Option B:** Promoting resorption is the primary function of **PTH** and **Vitamin D** (in high doses), which increase blood calcium. * **Option C:** Calcitonin has a unidirectional effect on bone; it is purely anti-resorptive and does not stimulate resorption under any physiological condition. * **Option D:** While calcitonin prevents the breakdown of bone, it does not directly "enhance" the complex process of mineralization (which requires adequate calcium, phosphate, and alkaline phosphatase activity). Its effect is passive preservation rather than active formation. **High-Yield Clinical Pearls for NEET-PG:** * **Marker:** Serum calcitonin is a sensitive tumor marker for **Medullary Thyroid Carcinoma (MTC)**. * **Therapeutic Use:** Exogenous calcitonin (often Salmon calcitonin due to higher potency) is used in the acute management of **Hypercalcemic crisis**, **Paget’s disease of bone**, and to provide analgesic effects in **osteoporotic vertebral fractures**. * **Escape Phenomenon:** The hypocalcemic effect of calcitonin is short-lived because osteoclasts eventually "downregulate" their receptors, a process known as tachyphylaxis or the "escape phenomenon." [1]

Question 357: Which of the following is NOT a feature of primary hyperaldosteronism?

A. Hypokalemia
B. Hypertension
C. Hypernatremia
D. Increased renin level (Correct Answer)

Explanation: ### Explanation **Primary Hyperaldosteronism (Conn’s Syndrome)** is characterized by the autonomous overproduction of aldosterone from the adrenal cortex (most commonly due to an adrenal adenoma or bilateral adrenal hyperplasia). **Why "Increased renin level" is the correct answer:** In primary hyperaldosteronism, the excess aldosterone leads to sodium and water retention, which increases effective circulating volume and blood pressure. This physiological state triggers a **negative feedback mechanism** on the juxtaglomerular apparatus, resulting in the **suppression of renin**. Therefore, a **low plasma renin level** is a hallmark of the disease. An increased renin level would instead point toward *secondary* hyperaldosteronism (e.g., renal artery stenosis). **Analysis of Incorrect Options:** * **A. Hypokalemia:** Aldosterone acts on the principal cells of the collecting duct to secrete potassium into the urine. Chronic excess leads to significant depletion of serum potassium. * **B. Hypertension:** Increased sodium reabsorption in the distal nephron leads to volume expansion, making hypertension a cardinal clinical feature. * **C. Hypernatremia:** While sodium is retained, it is often "mild" due to the **Aldosterone Escape Phenomenon** (where ANP release prevents massive edema); however, serum sodium levels typically remain at the high end of normal or slightly elevated. **NEET-PG High-Yield Pearls:** * **Screening Test of Choice:** Plasma Aldosterone Concentration (PAC) to Plasma Renin Activity (PRA) ratio. A **PAC:PRA ratio > 20-30** is highly suggestive. * **Confirmatory Test:** Saline infusion test (failure to suppress aldosterone) or Oral Salt Loading test. * **Metabolic State:** Patients typically exhibit **Metabolic Alkalosis** (due to H+ secretion in the intercalated cells). * **Clinical Clue:** Suspect this in a young patient with resistant hypertension and unexplained hypokalemia.

Question 358: An 83-year-old man with poor nutrition presents with easy bruising and bleeding gums. On examination, he has inflamed bleeding gums, multiple areas of ecchymoses, and perifollicular hemorrhages. His coagulation profile and liver function tests are normal. What is the most likely diagnosis for this patient's vitamin deficiency or excess?

A. niacin
B. thiamine
C. pyridoxine
D. vitamin C (Correct Answer)

Explanation: The clinical presentation of **perifollicular hemorrhages**, **bleeding gums**, and **easy bruising** in an elderly patient with poor nutrition is pathognomonic for **Scurvy (Vitamin C deficiency)** [1]. **1. Why Vitamin C is correct:** Vitamin C (ascorbic acid) is a vital cofactor for the enzymes **prolyl and lysyl hydroxylase**, which are responsible for the hydroxylation of proline and lysine residues during **collagen synthesis** [4]. This process is essential for the cross-linking of collagen fibers. Deficiency leads to defective collagen formation, resulting in weakened capillary walls and connective tissue [1]. This manifests as: * **Hemorrhagic signs:** Perifollicular hemorrhages (corkscrew hairs), ecchymoses, and petechiae. * **Oral signs:** Swollen, friable, and bleeding gums (gingivitis) [1]. * **Impaired wound healing:** Due to the inability to form stable collagen [1]. **2. Why other options are incorrect:** * **Niacin (B3):** Deficiency causes **Pellagra**, characterized by the "3 Ds": Dermatitis (photosensitive Casal’s necklace [3]), Diarrhea, and Dementia. It does not typically cause bleeding manifestations. * **Thiamine (B1):** Deficiency leads to **Beriberi** (Dry: peripheral neuropathy; Wet: high-output heart failure) or **Wernicke-Korsakoff syndrome** [2]. * **Pyridoxine (B6):** Deficiency causes sideroblastic anemia, peripheral neuropathy, and seborrheic dermatitis, but not perifollicular hemorrhages. **3. NEET-PG High-Yield Pearls:** * **Classic Triad of Scurvy:** Anemia, Myalgia, and Dermatological signs (perifollicular hemorrhage). * **Bone findings (Pediatric Scurvy/Barlow’s Disease):** Subperiosteal hemorrhage, "Trümmerfeld zone" (fragmented bone), and "Wimberger ring sign" on X-ray. * **Lab Clue:** Coagulation studies (PT/aPTT) and platelet counts are **normal** in Scurvy; the bleeding is due to structural vessel wall weakness, not a clotting defect.

Question 359: A 60-year-old woman presents with concerns about osteoporosis due to her mother's recent hip fracture. She has a 50-pack-year smoking history, started hormone replacement therapy for 6 years after menopause at age 49, and has a BMI of 26.7 kg/m². She takes a multivitamin and levothyroxine 50 mg/d. Her exercise includes lawn mowing and gardening. What is the most appropriate recommendation for osteoporosis screening for this patient?

A. Nuclear medicine bone scan
B. Dual-x-ray absorptiometry (DXA) scan (Correct Answer)
C. Quantitative CT bone densitometry
D. Peripheral bone densitometry

Explanation: **Explanation:** The gold standard for screening and diagnosing osteoporosis is **Dual-energy X-ray Absorptiometry (DXA)**. According to international guidelines (USPSTF and ISCD), screening is recommended for all women aged **≥65 years** and younger postmenopausal women (like this 60-year-old patient) who have an increased risk of fractures [1]. This patient has multiple risk factors: a positive family history (maternal hip fracture) and a significant smoking history [2]. * **Why DXA is the Correct Choice:** DXA measures Bone Mineral Density (BMD) at the hip and lumbar spine. It is the preferred method because of its high precision, short scan time, low radiation exposure, and its ability to predict fracture risk and monitor response to therapy [2]. **Analysis of Incorrect Options:** * **A. Nuclear medicine bone scan:** This uses technetium-99m to detect increased bone turnover (e.g., metastases, osteomyelitis, or occult fractures). It cannot measure bone density or diagnose osteoporosis. * **C. Quantitative CT (QCT):** While it provides a 3D measurement of bone density, it involves significantly higher radiation doses and is more expensive than DXA. It is not used for routine screening. * **D. Peripheral bone densitometry:** This measures density at the wrist or heel. While useful for mass screening in resource-limited settings, it is less predictive of hip fracture risk and cannot be used for monitoring treatment. **NEET-PG Clinical Pearls:** * **T-score:** Compares patient BMD to a young-adult reference population. * Normal: ≥ -1.0 * – Osteopenia: -1.0 to -2.5 * **Osteoporosis: ≤ -2.5** * **Z-score:** Compares patient BMD to an age-matched population (used for premenopausal women and men <50). * **FRAX Tool:** Used to calculate the 10-year probability of a major osteoporotic fracture [2].

Question 360: Gynaecomastia may be seen in all of the following conditions except?

A. Klinefelter syndrome
B. Cirrhosis of liver
C. Cryptorchidism (Correct Answer)
D. Sex cord tumour of Sertoli cells

Explanation: Gynecomastia is the benign proliferation of glandular breast tissue in males, caused by an imbalance between estrogen and androgen action [1]. **Why Cryptorchidism is the correct answer:** Cryptorchidism (undescended testes) is a developmental defect where the testes fail to descend into the scrotum. While it is a major risk factor for **testicular germ cell tumors** and **infertility**, it does not inherently cause an endocrine imbalance (excess estrogen or low testosterone) sufficient to produce gynecomastia unless it is part of a broader syndrome [1]. **Analysis of other options:** * **Klinefelter Syndrome (47, XXY):** This is the most common congenital cause of primary hypogonadism [2]. Elevated gonadotropins (LH/FSH) lead to increased aromatization of testosterone to estrogen, making gynecomastia a hallmark clinical feature (seen in ~80% of cases) [1]. * **Cirrhosis of Liver:** The liver is responsible for metabolizing estrogen and producing Sex Hormone Binding Globulin (SHBG). In cirrhosis, decreased estrogen clearance and increased peripheral conversion of androgens to estrogens lead to gynecomastia. * **Sertoli Cell Tumors:** These are sex cord-stromal tumors that can actively secrete estrogens or increase aromatase activity, directly leading to feminizing symptoms including gynecomastia [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Drugs causing Gynecomastia (Mnemonic: DISCO):** **D**igoxin, **I**soniazid, **S**pironolactone (most common), **C**imetidine, **O**estrogens/Ketoconazole. * **Physiological Gynecomastia:** Occurs in three peaks—Neonatal, Pubertal, and Senile (old age) [1]. * **Spironolactone** causes gynecomastia by displacing androgens from their receptors and increasing peripheral conversion to estrogen. * **Reassurance** is the management of choice for pubertal gynecomastia as it usually resolves spontaneously within 1–2 years [1].

Practice by Chapter

Diabetes Mellitus

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Thyroid Disorders

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Adrenal Gland Disorders

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Pituitary Disorders

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Calcium and Bone Metabolism

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Reproductive Endocrinology

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Lipid Disorders

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Endocrine Hypertension

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Multiple Endocrine Neoplasia

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Obesity and Metabolic Syndrome

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Neuroendocrine Tumors

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Endocrine Emergencies

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