Endocrinology — MCQs
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Which of the following is the most common cause of insulin resistance?
Which of the following is NOT a common symptom of pheochromocytoma?
A 65-year-old man presents with vision loss, headaches, cold intolerance, and unintentional weight gain of 5kg in 3 months. Examination reveals bitemporal hemianopia and a pulse of 50 bpm. A thyroid function test is ordered. Which of the following test results is most likely to be seen in this patient?
Goitrous hypothyroidism commonly occurs in all of the following conditions except?
Which of the following is the most common cause of hypergonadotropic hypogonadism in males?
Which of the following is NOT a common clinical manifestation of thyrotoxicosis?
Recurrent balanoposthitis is commonly seen in which of the following conditions?
Autonomic neuropathy is characterized by all of the following except:
Which of the following are symptoms of hyperthyroidism?
A 25-year-old male presents with occasional severe headaches, nausea, and vomiting. Blood pressure while sitting is 230/130 mmHg with a heart rate of 90 beats/min. Upon standing, the blood pressure drops to 200/100 mmHg and the heart rate increases to 140 beats/min. Cardiovascular examination reveals tachycardia with normal S1 and S2 sounds. The patient's lungs are clear. Optic discs are blurred, but there are no exudates or hemorrhages. Select the appropriate treatment for this condition.
Endocrinology Indian Medical PG Practice Questions and MCQs
Question 191: Which of the following is the most common cause of insulin resistance?
- A. Obesity (Correct Answer)
- B. Post-receptor defects
- C. Liver dysfunction
- D. Pancreatic dysfunction
Explanation: **Explanation:** **1. Why Obesity is the Correct Answer:** Obesity is the most common cause of insulin resistance worldwide. The underlying mechanism involves the release of **Free Fatty Acids (FFAs)** and pro-inflammatory **adipokines** (such as TNF-alpha, IL-6, and Resistin) from excess adipose tissue [1]. These substances interfere with the insulin signaling pathway, specifically inhibiting the phosphorylation of Insulin Receptor Substrates (IRS). Furthermore, obesity leads to a decrease in **Adiponectin**, a hormone that normally enhances insulin sensitivity [2]. **2. Why the Other Options are Incorrect:** * **Post-receptor defects:** While post-receptor signaling abnormalities (like impaired GLUT-4 translocation) are the actual *molecular* mechanism of resistance, they are usually secondary to obesity or genetic syndromes [2]. They are not the "cause" in a clinical epidemiological sense. * **Liver dysfunction:** While the liver is a primary site of insulin action, liver disease (like NAFLD) is more often a *consequence* or a co-morbidity of insulin resistance rather than its primary inciting cause. * **Pancreatic dysfunction:** This typically refers to impaired insulin *secretion* (Beta-cell failure), which leads to Type 2 Diabetes progression, but it does not cause resistance to the insulin already present in the system [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Acanthosis Nigricans:** The most common clinical cutaneous marker of insulin resistance. * **Metabolic Syndrome:** Insulin resistance is the pathophysiological hallmark, characterized by abdominal obesity, hypertension, and dyslipidemia [1]. * **Gold Standard Investigation:** The **Hyperinsulinemic Euglycemic Clamp** is the gold standard for measuring insulin resistance, though HOMA-IR is more commonly used in research. * **PCOS:** A very common cause of insulin resistance in young females, often independent of BMI but exacerbated by obesity.
Question 192: Which of the following is NOT a common symptom of pheochromocytoma?
- A. Headache
- B. Palpitations
- C. Abdominal pain
- D. Hypotension (Correct Answer)
Explanation: Pheochromocytoma is a catecholamine-secreting tumor arising from the chromaffin cells of the adrenal medulla. The clinical presentation is primarily driven by the excessive release of epinephrine and norepinephrine [2]. **Why Hypotension is the Correct Answer:** The hallmark of pheochromocytoma is **Hypertension**, not hypotension. Excess catecholamines cause potent vasoconstriction (via $\alpha_1$ receptors) and increased cardiac output (via $\beta_1$ receptors), leading to persistent or paroxysmal high blood pressure [2]. While "orthostatic hypotension" can occasionally occur due to low plasma volume and impaired autonomic reflexes, absolute hypotension is not a common or characteristic symptom [1]. **Why the other options are incorrect:** * **Headache (A):** This is the most common symptom (seen in ~90% of symptomatic patients). It is typically paroxysmal, severe, and bilateral. * **Palpitations (B):** Excess catecholamines increase the heart rate and myocardial contractility, leading to forceful or rapid heartbeats [2]. * **Abdominal pain (C):** While less famous than the "classic triad," abdominal pain can occur due to catecholamine-induced mesenteric vasoconstriction or the mass effect of the tumor itself. **High-Yield Clinical Pearls for NEET-PG:** * **The Classic Triad:** Episodic **P**alpitations, **H**ache, and **D**iaphoresis (P-H-D). * **Rule of 10s:** 10% are bilateral, 10% are extra-adrenal (Paragangliomas), 10% are malignant, and 10% are familial. * **Diagnosis:** Best initial screening test is **24-hour urinary fractionated metanephrines** or plasma free metanephrines. * **Management:** Always start **Alpha-blockers first** (e.g., Phenoxybenzamine) before Beta-blockers to prevent a hypertensive crisis caused by unopposed alpha-mediated vasoconstriction [1].
Question 193: A 65-year-old man presents with vision loss, headaches, cold intolerance, and unintentional weight gain of 5kg in 3 months. Examination reveals bitemporal hemianopia and a pulse of 50 bpm. A thyroid function test is ordered. Which of the following test results is most likely to be seen in this patient?
- A. TSH: Low, Free T4: Low, Free T3: Low (Correct Answer)
- B. TSH: High, Free T4: Low, Free T3: Low
- C. TSH: High, Free T4: Normal, Free T3: Normal
- D. TSH: Low, Free T4: High, Free T3: High
Explanation: ### Explanation **1. Why Option A is Correct:** The patient presents with a classic triad suggesting a **Pituitary Macroadenoma** causing **Secondary (Central) Hypothyroidism**. * **Mass Effect:** Bitemporal hemianopia (compression of the optic chiasm) and headaches indicate a large pituitary tumor [1]. * **Hypothyroid Symptoms:** Cold intolerance, weight gain, and bradycardia (50 bpm) indicate low thyroid hormone levels [1]. * **Pathophysiology:** In central hypothyroidism, the pituitary gland fails to secrete adequate **TSH**. Consequently, the thyroid gland is not stimulated, leading to low **Free T4 and T3**. Unlike primary hypothyroidism, the TSH is typically low or inappropriately "normal" despite low T4 levels [1]. **2. Why Other Options are Incorrect:** * **Option B (High TSH, Low T4/T3):** This pattern represents **Primary Hypothyroidism** (e.g., Hashimoto’s). While it explains the systemic symptoms, it does not account for the bitemporal hemianopia (a neurological mass effect). * **Option C (High TSH, Normal T4/T3):** This represents **Subclinical Hypothyroidism**. The patient’s symptoms (bradycardia, significant weight gain) suggest overt, not subclinical, disease. * **Option D (Low TSH, High T4/T3):** This pattern represents **Hyperthyroidism** (e.g., Graves’ disease), which would present with heat intolerance, weight loss, and tachycardia—the opposite of this patient's presentation. **3. Clinical Pearls for NEET-PG:** * **Bitemporal Hemianopia:** Always think of a pituitary adenoma or craniopharyngioma compressing the optic chiasm [1]. * **Central Hypothyroidism Rule:** If T4 is low but TSH is not elevated, look for a pituitary or hypothalamic cause [1]. * **Management Caution:** In suspected panhypopituitarism, **always rule out or treat adrenal insufficiency (with steroids) before starting Levothyroxine** to avoid precipitating an acute adrenal crisis [1]. * **Most common pituitary hormone deficiency:** Growth Hormone (GH) is usually the first to be lost in progressive pituitary compression, followed by LH/FSH, then TSH.
Question 194: Goitrous hypothyroidism commonly occurs in all of the following conditions except?
- A. Hashimoto's thyroiditis
- B. Dyshoromonogenesis
- C. Thyroprivic hypothyroidism (Correct Answer)
- D. Iodine deficiency
Explanation: The core concept behind **Goitrous Hypothyroidism** is the compensatory hypertrophy of the thyroid gland. When thyroid hormone levels (T3/T4) fall, the pituitary gland increases the secretion of **TSH** [2]. If the thyroid tissue is present and capable of responding, TSH stimulates glandular growth, leading to a goiter. **Why Thyroprivic Hypothyroidism is the correct answer:** "Thyroprivic" refers to the **loss or absence of thyroid tissue**. This occurs in conditions like thyroid agenesis (congenital), surgical removal (thyroidectomy), or total destruction via radioactive iodine therapy [1]. Since there is little to no thyroid tissue left to respond to TSH stimulation, a goiter cannot form. This is a "non-goitrous" form of hypothyroidism. **Analysis of Incorrect Options:** * **Hashimoto’s Thyroiditis:** This is the most common cause of goitrous hypothyroidism in iodine-sufficient areas. Lymphocytic infiltration and TSH stimulation lead to a firm, rubbery goiter. * **Dyshormonogenesis:** These are genetic defects in the enzymatic pathways of thyroid hormone synthesis (e.g., Pendred syndrome) [1]. The biosynthetic block leads to low T4, high TSH, and subsequent thyroid enlargement. * **Iodine Deficiency:** The most common cause of goitrous hypothyroidism worldwide (Endemic Goiter). Lack of iodine prevents hormone synthesis, triggering a massive TSH response and glandular hypertrophy. **High-Yield Clinical Pearls for NEET-PG:** * **Wolff-Chaikoff Effect:** Goitrous hypothyroidism induced by excessive iodine intake (e.g., Amiodarone). * **Pendred Syndrome:** Characterized by dyshormonogenetic goiter and sensorineural deafness. * **Most common cause of Goiter:** Iodine deficiency (Worldwide); Hashimoto’s (Developed nations). * **Thyroprivic vs. Trophoprivic:** Thyroprivic is a primary thyroid tissue loss; Trophoprivic refers to secondary hypothyroidism due to loss of TSH (pituitary failure).
Question 195: Which of the following is the most common cause of hypergonadotropic hypogonadism in males?
- A. Viral orchitis
- B. Klinefelter's syndrome (Correct Answer)
- C. Kallman's syndrome
- D. Noonan syndrome
Explanation: **Explanation:** **Hypergonadotropic hypogonadism** (Primary Hypogonadism) is characterized by testicular failure leading to low testosterone levels, which results in a compensatory rise in gonadotropins (FSH and LH) due to the loss of negative feedback on the pituitary gland [1]. **Why Klinefelter’s Syndrome is correct:** Klinefelter’s syndrome (47, XXY) is the **most common congenital cause** and the most common cause overall of primary testicular failure [1]. The extra X chromosome leads to progressive hyalinization and fibrosis of the seminiferous tubules and dysfunction of Leydig cells [1]. This results in azoospermia, low testosterone, and characteristically elevated FSH and LH levels [1]. **Analysis of Incorrect Options:** * **Viral Orchitis (e.g., Mumps):** While it is a common *acquired* cause of testicular atrophy, it is less frequent than Klinefelter’s syndrome in the general population presenting with hypogonadism [1]. * **Kallmann’s Syndrome:** This is a form of **hypogonadotropic hypogonadism** (Secondary Hypogonadism). It is caused by a failure of GnRH-secreting neurons to migrate, leading to low FSH/LH and low testosterone, often associated with anosmia. * **Noonan Syndrome:** Often called the "Male Turner Syndrome," it can cause cryptorchidism and primary hypogonadism, but it is significantly rarer than Klinefelter’s syndrome [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Karyotype:** 47, XXY is the most common; Barr bodies are present on buccal smear. * **Clinical Features:** Tall stature, eunuchoid body proportions, gynecomastia, small firm testes (<2 cm), and female-pattern hair distribution [1]. * **Biochemical Profile:** ↓ Testosterone, ↑ FSH, ↑ LH, and ↑ Estradiol [1]. * **Risk:** Increased risk of breast cancer (20x) and extragonadal germ cell tumors (mediastinal) [1].
Question 196: Which of the following is NOT a common clinical manifestation of thyrotoxicosis?
- A. Gynaecomastia
- B. Loss of libido
- C. Goiter
- D. Weight gain (Correct Answer)
Explanation: ### Explanation **Correct Answer: D. Weight gain** **1. Why Weight Gain is the Correct Answer:** Thyrotoxicosis is a hypermetabolic state caused by an excess of circulating thyroid hormones ($T_3$ and $T_4$). These hormones increase the **Basal Metabolic Rate (BMR)** by stimulating Na+/K+ ATPase activity and increasing thermogenesis [2]. Despite a typically increased appetite (polyphagia), the body consumes calories faster than they are ingested, leading to **weight loss** [2]. Weight gain is a hallmark of *hypothyroidism*, not thyrotoxicosis. **2. Analysis of Incorrect Options:** * **A. Gynaecomastia:** This is a recognized manifestation of thyrotoxicosis in men. Excess thyroid hormones increase the production of **Sex Hormone-Binding Globulin (SHBG)** and stimulate the peripheral conversion of androgens to estrogens, altering the estrogen-to-testosterone ratio. * **B. Loss of Libido:** Both hyper- and hypothyroidism can cause reproductive dysfunction. In thyrotoxicosis, elevated SHBG levels and altered hypothalamic-pituitary-gonadal axis feedback often lead to decreased libido and erectile dysfunction in men, and menstrual irregularities (oligomenorrhea) in women. * **C. Goiter:** A goiter (enlarged thyroid gland) is frequently present in many causes of thyrotoxicosis, most notably in **Graves' disease** (diffuse goiter) and **Toxic Multinodular Goiter** [2]. **3. NEET-PG High-Yield Clinical Pearls:** * **Apathetic Hyperthyroidism:** Seen in the elderly; patients may present with depression, lethargy, and weight loss rather than classic hyperactivity. * **Cardiovascular Signs:** Sinus tachycardia and **Atrial Fibrillation** (especially in elderly patients) are high-yield associations [1]. * **Neuromuscular:** Look for fine tremors and **proximal myopathy** (difficulty climbing stairs or rising from a chair) [2], [3]. * **Exception to Weight Loss:** Occasionally, young patients with Graves' disease may experience weight gain due to a massive increase in appetite that overcompensates for the hypermetabolic state.
Question 197: Recurrent balanoposthitis is commonly seen in which of the following conditions?
- A. Diabetes Mellitus (Correct Answer)
- B. Herpes simplex
- C. Smoking
- D. Alcohol consumption
Explanation: **Explanation:** **Recurrent balanoposthitis** (inflammation of the glans penis and prepuce) is a classic clinical marker for **Diabetes Mellitus (DM)**. In many cases, it is the initial presenting symptom that leads to a new diagnosis of Type 2 DM. **1. Why Diabetes Mellitus is the Correct Answer:** The underlying mechanism is primarily due to **hyperglycosuria** (glucose in the urine). The presence of sugar on the skin of the genital area provides an ideal culture medium for fungi, specifically *Candida albicans*. Furthermore, hyperglycemia impairs neutrophil function and cell-mediated immunity, making diabetic patients more susceptible to persistent and recurrent fungal infections. Chronic inflammation can eventually lead to acquired phimosis. **2. Analysis of Incorrect Options:** * **Herpes Simplex (HSV):** While HSV causes genital ulcers (vesicles on an erythematous base), it typically presents as episodic painful sores rather than generalized inflammation of the glans (balanitis). It is not the "most common" cause of generalized recurrent balanoposthitis in clinical practice compared to DM. * **Smoking & Alcohol consumption:** These are general risk factors for various systemic diseases but have no direct causal or strong statistical link to the development of balanoposthitis. **Clinical Pearls for NEET-PG:** * **High-Yield Association:** In any uncircumcised male presenting with recurrent balanoposthitis or fungal infections, the first investigation to perform is a **Fast Blood Sugar (FBS) or HbA1c**. * **SGLT-2 Inhibitors:** Modern diabetes medications like Dapagliflozin increase urinary glucose excretion and are notorious for causing an increased risk of genital mycotic infections (balanoposthitis in men, vulvovaginitis in women). * **Pathogen:** *Candida albicans* is the most common organism isolated in diabetic balanoposthitis.
Question 198: Autonomic neuropathy is characterized by all of the following except:
- A. Gustatory sweating (Correct Answer)
- B. Tachycardia
- C. Diarrhoea
- D. Pupillary dilatation
Explanation: Autonomic neuropathy is a common complication of long-standing diabetes mellitus, affecting both the sympathetic and parasympathetic nervous systems [1]. **Why "Gustatory Sweating" is the correct answer (The Exception):** In the context of this specific question format (often seen in older NEET-PG/AIIMS patterns), **Gustatory Sweating** is considered a feature of autonomic neuropathy [1]. However, the question asks for the "except" option. There is a frequent clinical distinction made: while autonomic neuropathy causes *anhidrosis* (lack of sweating) in the lower extremities, it causes **compensatory hyperhidrosis** or **gustatory sweating** (sweating while eating) in the upper body [1]. In many standardized exams, if "Pupillary dilatation" is listed alongside "Gustatory sweating," the examiner is testing the specific pupillary reflex. Autonomic neuropathy typically causes a **constricted pupil (miosis)** that is slow to dilate in the dark, rather than active pupillary dilatation [1]. *Note: There is often debate on this question; however, in autonomic failure, the pupil is typically small due to sympathetic denervation.* **Analysis of other options:** * **Tachycardia:** Resting tachycardia is one of the earliest signs of cardiac autonomic neuropathy due to the loss of vagal (parasympathetic) inhibition [1]. * **Diarrhoea:** Diabetic autonomic neuropathy affects the GI tract, leading to "diabetic diarrhea," which is typically nocturnal and painless [1]. * **Pupillary dilatation:** As mentioned, the hallmark is actually a **small, miotic pupil** and a decreased diameter in darkness due to sympathetic dysfunction [1]. **NEET-PG High-Yield Pearls:** * **Cardiovascular:** Orthostatic hypotension (drop in SBP >20 mmHg) and fixed heart rate [1]. * **Gastrointestinal:** Gastroparesis (delayed emptying) and nocturnal diarrhea [1]. * **Genitourinary:** Neurogenic bladder (overflow incontinence) and erectile dysfunction [1]. * **Sudomotor:** Distal anhidrosis with proximal compensatory sweating [1].
Question 199: Which of the following are symptoms of hyperthyroidism?
- A. Muscle weakness
- B. Weight loss
- C. Lid lag
- D. All of the above (Correct Answer)
Explanation: **Explanation:** Hyperthyroidism is a clinical syndrome resulting from excessive circulating thyroid hormones ($T_3$ and $T_4$), which leads to a generalized hypermetabolic state and increased sympathetic nervous system activity [1]. **Why "All of the above" is correct:** * **Muscle Weakness (Option A):** Excess thyroid hormone promotes a catabolic state, leading to protein breakdown. This results in **proximal myopathy**, where patients typically struggle with tasks like climbing stairs or rising from a chair [2]. * **Weight Loss (Option B):** Despite an increased appetite (polyphagia), patients experience weight loss due to a significantly elevated **Basal Metabolic Rate (BMR)** and increased thermogenesis [1]. * **Lid Lag (Option C):** This is a classic sign of sympathetic overactivity. Increased adrenergic tone causes contraction of the **Müller’s muscle** (superior tarsal muscle), leading to the characteristic "lid lag" (von Graefe’s sign) where the upper eyelid does not follow the downward movement of the eyeball smoothly. **Clinical Pearls for NEET-PG:** 1. **Cardiovascular:** Sinus tachycardia and **Atrial Fibrillation** (especially in elderly patients) are high-yield associations [3]. 2. **Neuromuscular:** Look for fine tremors, hyperreflexia, and anxiety [1]. 3. **Graves’ Disease Specifics:** While lid lag is seen in all forms of thyrotoxicosis, **Exophthalmos** (proptosis) and **Pretibial Myxedema** are specific to Graves’ disease due to TSH-receptor antibody activity [1], [2]. 4. **Apathetic Hyperthyroidism:** In elderly patients, typical symptoms may be absent; they may present only with weight loss or new-onset AFib.
Question 200: A 25-year-old male presents with occasional severe headaches, nausea, and vomiting. Blood pressure while sitting is 230/130 mmHg with a heart rate of 90 beats/min. Upon standing, the blood pressure drops to 200/100 mmHg and the heart rate increases to 140 beats/min. Cardiovascular examination reveals tachycardia with normal S1 and S2 sounds. The patient's lungs are clear. Optic discs are blurred, but there are no exudates or hemorrhages. Select the appropriate treatment for this condition.
- A. Labetalol
- B. Nitroprusside
- C. Phentolamine (Correct Answer)
- D. Hydralazine
Explanation: ### Explanation **Diagnosis: Pheochromocytoma (Hypertensive Crisis)** The clinical presentation of paroxysmal hypertension, headache, and tachycardia, combined with **orthostatic hypotension** (a drop in BP despite high baseline levels), is classic for **Pheochromocytoma**. The blurred optic discs indicate hypertensive urgency/emergency. Orthostatic hypotension in these patients occurs due to chronic catecholamine-induced vasoconstriction leading to a contracted intravascular volume. **1. Why Phentolamine is Correct:** In a hypertensive crisis caused by Pheochromocytoma, the immediate goal is to counteract the massive surge of catecholamines. **Phentolamine** is a rapid-acting, non-selective **alpha-adrenergic antagonist**. It directly blocks the alpha-1 receptors responsible for severe vasoconstriction, thereby lowering blood pressure effectively. It is the drug of choice for the acute management of catecholamine-excess states. **2. Why Other Options are Incorrect:** * **Labetalol (A):** While it has both alpha and beta-blocking properties, the beta-blockade outweighs the alpha-blockade (ratio 1:7). Administering it first can lead to **"unopposed alpha-stimulation,"** causing a paradoxical rise in blood pressure. * **Nitroprusside (B):** While a potent vasodilator used in hypertensive emergencies, it does not address the underlying catecholamine surge and is generally a second-line agent after alpha-blockade in this specific scenario. * **Hydralazine (D):** This is a direct vasodilator primarily used in pregnancy-induced hypertension. It can cause reflex tachycardia, which would worsen the patient's already high heart rate. **3. Clinical Pearls for NEET-PG:** * **Rule of 10s:** 10% bilateral, 10% malignant, 10% extra-adrenal (Paraganglioma), 10% pediatric, 10% familial. * **Sequence of Blockade:** Always give **Alpha-blockers first** (e.g., Phenoxybenzamine or Phentolamine), then Beta-blockers. Reversing this order can trigger a fatal hypertensive crisis. * **Triad:** Episodic headache, sweating, and tachycardia. * **Screening:** 24-hour urinary fractionated metanephrines and catecholamines or plasma metanephrines.
Practice by Chapter
Diabetes Mellitus
Practice Questions
Thyroid Disorders
Practice Questions
Adrenal Gland Disorders
Practice Questions
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
Practice Questions
Obesity and Metabolic Syndrome
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Neuroendocrine Tumors
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Endocrine Emergencies
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