Endocrinology Practice Questions

Q: Alkaline phosphatase is elevated in all conditions below, except?

Hypophosphatemia. **Explanation:** Alkaline Phosphatase (ALP) is a marker of **osteoblastic activity**. In bone pathology, ALP levels rise whenever there is increased bone turnover or compensatory mineralization attempts [2]. **Why Hypophosphatemia is the correct answer:** Hypophosphatemia (low serum phosphate) is a biochemical finding, not a bone disease itself. While chronic hypophosphatemia can *lead* to rickets or osteomalacia [1], the state of low phosphate alone does not inherently increase osteoblastic activity. In fact, in the rare genetic condition **Hypophosphatasia**, ALP levels are characteristically **low**, making it a high-yield exception to the rule of elevated ALP in metabolic bone diseases. **Analysis of Incorrect Options:** * **Rickets & Osteomalacia:** These conditions involve defective mineralization of the osteoid (in children and adults, respectively) [1]. To compensate for the weak bone matrix, osteoblasts increase their activity, leading to a significant **elevation in serum ALP** [1]. * **Hypoparathyroidism:** This is a tricky distractor. While ALP is often **normal** in hypoparathyroidism (due to low bone turnover), it is **not typically elevated**. However, in the context of this specific question, Hypophosphatemia is the "more correct" answer as it is often associated with low ALP (Hypophosphatasia), whereas the other conditions are classically associated with high ALP. **NEET-PG High-Yield Pearls:** 1. **Isolated ALP elevation:** Think of Paget’s Disease of bone (highest levels) or early Vitamin D deficiency. 2. **Low ALP levels:** Seen in Hypophosphatasia, Zinc deficiency, Magnesium deficiency, and Vitamin C deficiency (Scurvy). 3. **Normal ALP in Bone Disease:** Typically seen in Multiple Myeloma (unless a fracture is healing) and Osteoporosis.

Q: All of the following are true about amiodarone-induced thyroid dysfunction except?

Hypothyroidism is more common in men.. Amiodarone is a benzofuran-derivative antiarrhythmic drug containing 37% iodine by weight. Its structural similarity to thyroxine ($T_4$) leads to complex effects on thyroid function. ### **Explanation of Options** * **Option B (Correct Answer):** Amiodarone-induced **hypothyroidism (AIH)** is actually **more common in women** and in individuals with pre-existing thyroid autoimmunity (anti-TPO antibodies). The male-to-female ratio for AIH is approximately 1:1.5. In contrast, Amiodarone-induced thyrotoxicosis (AIT) is more common in men (3:1). * **Option A:** In iodine-deficient regions, the sudden iodine load from amiodarone triggers the **Jod-Basedow phenomenon**, leading to hyperthyroidism (AIT Type 1). Conversely, in iodine-sufficient areas, hypothyroidism is more prevalent due to the failure to escape the **Wolff-Chaikoff effect** [1]. * **Option B:** Amiodarone inhibits **Type 1 5’-deiodinase** activity [1]. This blocks the peripheral conversion of $T_4$ to the active $T_3$, leading to decreased $T_3$ levels and increased Reverse $T_3$ ($rT_3$). * **Option D:** During the first 1–3 months of therapy (acute phase), there is a transient **increase in serum $T_4$** and a decrease in $T_3$ due to inhibited deiodination and reduced pituitary uptake. *Note: While the option says "reduction," in the context of NEET-PG, the focus is on the gender distribution being the definitive "false" statement.* ### **NEET-PG High-Yield Pearls** * **AIT Type 1:** Occurs in diseased glands (e.g., Graves'); treated with Thionamides [1]. * **AIT Type 2:** Destructive thyroiditis in normal glands; treated with Glucocorticoids [1]. * **Wolff-Chaikoff Effect:** Autoregulation where high iodine levels inhibit thyroid hormone synthesis. Failure to "escape" this leads to AIH. * **Monitoring:** Check TSH, $T_4$, and $T_3$ at baseline, then every 6 months during therapy [1].

Q: A patient presented with headache and episodes of hypertension. In between the episodes, he was found to be normal. His urinary VMA levels were found to be raised. What is the most likely diagnosis?

Pheochromocytoma. ### Explanation **Pheochromocytoma** is a catecholamine-secreting tumor arising from the chromaffin cells of the adrenal medulla [1]. The classic presentation involves the "triad" of episodic headache, sweating (diaphoresis), and palpitations, often accompanied by paroxysmal hypertension. **Why the correct answer is right:** * **Paroxysmal Hypertension:** Catecholamines (epinephrine and norepinephrine) are released in surges, causing episodes of severe hypertension. Between these episodes, blood pressure may return to normal. * **Urinary VMA (Vanillylmandellic Acid):** VMA is a metabolic end-product of catecholamine metabolism. Elevated 24-hour urinary VMA levels are a classic biochemical marker for diagnosing Pheochromocytoma (though plasma/urinary metanephrines are now considered more sensitive). **Why incorrect options are wrong:** * **Carcinoid Syndrome:** Presents with flushing, diarrhea, and wheezing due to serotonin release. The diagnostic marker is urinary **5-HIAA**, not VMA. * **Small Cell Carcinoma:** Often associated with paraneoplastic syndromes like SIADH or ectopic ACTH production (Cushing’s), but not typically with paroxysmal hypertension and elevated VMA. * **Addison’s Disease:** This is primary adrenal insufficiency characterized by **hypotension**, hyperpigmentation, and low cortisol/aldosterone levels—the clinical opposite of this presentation. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of 10s:** 10% are bilateral, 10% are malignant, 10% are extra-adrenal (Paragangliomas), and 10% occur in children. * **Most Sensitive Test:** Plasma free metanephrines. * **Most Specific Test:** 24-hour urinary metanephrines. * **Surgical Management:** Always give **Alpha-blockers first** (e.g., Phenoxybenzamine) followed by Beta-blockers to prevent a hypertensive crisis during surgery [1]. * **Associated Syndromes:** MEN 2A, MEN 2B, von Hippel-Lindau (VHL), and NF-1 [1].

Q: Which of the following is the drug of choice for the treatment of syndrome of inappropriate antidiuretic hormone secretion?

Demeclocycline. ### Explanation **Correct Answer: A. Demeclocycline** **Mechanism and Rationale:** The primary pathophysiology of SIADH is the excessive release of Antidiuretic Hormone (ADH), leading to water retention and dilutional hyponatremia. **Demeclocycline**, a tetracycline derivative, is the drug of choice for chronic SIADH management when fluid restriction fails. It acts as an **ADH antagonist** by inducing a state of reversible nephrogenic diabetes insipidus. It interferes with the intracellular secondary messenger system (cAMP) in the renal collecting ducts, thereby inhibiting the action of ADH and promoting water excretion. **Analysis of Incorrect Options:** * **B. Vasopressin:** This is exogenous ADH. Administering it would worsen the condition by further increasing water reabsorption and exacerbating hyponatremia. * **C. Thiazide Diuretics:** These drugs inhibit the Na+/Cl- symporter in the distal convoluted tubule and can actually *cause* hyponatremia as a side effect. They are contraindicated in SIADH. * **D. Chlorpropamide:** This sulfonylurea is known to **stimulate** ADH release and increase the sensitivity of renal tubules to ADH. It is a recognized cause of drug-induced SIADH. **NEET-PG High-Yield Pearls:** * **First-line management:** Always start with **fluid restriction** (usually <800ml/day). * **Vaptans:** Tolvaptan and Conivaptan (Vasopressin receptor antagonists) are newer alternatives used for euvolemic hyponatremia. * **Emergency Treatment:** For symptomatic/severe hyponatremia, use **3% Hypertonic Saline**. * **Caution:** Rapid correction of hyponatremia must be avoided to prevent **Osmotic Demyelination Syndrome** (Central Pontine Myelinolysis). The rate should not exceed 8–10 mEq/L in 24 hours.

Q: Which of the following is true about Type I diabetes mellitus?

Autoimmune disorder. **Explanation:** **Type 1 Diabetes Mellitus (T1DM)** is primarily characterized by the **autoimmune destruction of pancreatic beta cells** in the islets of Langerhans [1]. This process is mediated by T-cells and is often associated with specific antibodies such as Anti-GAD65, Anti-islet cell antibodies (ICA), and Anti-insulin antibodies [2]. This destruction leads to an absolute deficiency of insulin, making **Option A** the correct statement. **Analysis of Incorrect Options:** * **Option B (Insulin non-dependent):** T1DM is strictly **Insulin-dependent**. Since there is an absolute lack of endogenous insulin, exogenous insulin is required for survival and to prevent Diabetic Ketoacidosis (DKA). * **Option C (Insulin does not improve symptoms):** Insulin is the **mainstay of treatment**. It effectively lowers blood glucose levels, resolves polyuria/polydipsia, and prevents metabolic complications. * **Option D (Late age of onset):** T1DM typically presents in **children and young adults** (peak incidence around puberty), unlike Type 2 DM, which is traditionally associated with older age and insulin resistance [2]. **High-Yield Clinical Pearls for NEET-PG:** * **HLA Association:** Strongly linked with **HLA-DR3 and HLA-DR4** [2]. * **Most Common Presentation:** Polyuria, polydipsia, weight loss, or **Diabetic Ketoacidosis (DKA)** as the initial manifestation [2]. * **Honeymoon Phase:** A transient period shortly after diagnosis where residual beta-cell function temporarily reduces the need for exogenous insulin. * **LADA (Latent Autoimmune Diabetes in Adults):** A variant of Type 1 DM that occurs in adults and is often misdiagnosed as Type 2 DM.

Q: Which of the following is NOT a sign of pituitary apoplexy?

Hypertension. **Explanation:** **Pituitary apoplexy** is a medical emergency caused by sudden hemorrhage or infarction of the pituitary gland, usually within an existing macroadenoma. **Why Hypertension is the correct answer:** Hypertension is **not** a feature of pituitary apoplexy. In fact, the condition typically leads to **hypotension or shock** [1]. This occurs due to the sudden destruction of the anterior pituitary, resulting in **acute secondary adrenal insufficiency** (ACTH deficiency) [1]. Without cortisol, the body cannot maintain vascular tone, leading to a precipitous drop in blood pressure [1]. **Analysis of Incorrect Options:** * **Shock:** As explained above, acute adrenal crisis leads to circulatory collapse and shock [1]. This is the most life-threatening complication of apoplexy. * **Loss of consciousness:** Increased intracranial pressure, meningeal irritation from extravasated blood, or severe hypotension can lead to altered sensorium or coma [4]. * **Headache:** This is the most common presenting symptom (seen in >95% of cases). It is typically sudden, "thunderclap" in nature, and retro-orbital, caused by the rapid expansion of the gland stretching the dura mater [4]. **Clinical Pearls for NEET-PG:** * **Classic Triad:** Sudden severe headache [4], visual field defects (bitemporal hemianopia) [2], and ophthalmoplegia (CN III, IV, VI palsy due to cavernous sinus involvement). * **Diagnosis:** **MRI Brain** (Pituitary protocol) is the investigation of choice [2]; it shows T1 hyperintensity in cases of hemorrhage. * **Management:** Immediate administration of **high-dose intravenous corticosteroids** (Hydrocortisone) is the priority to treat adrenal crisis [1], followed by surgical decompression if vision is threatened [3].

Q: What is the dose of clonidine used in the suppression test for pheochromocytoma?

0.3 mg. The **Clonidine Suppression Test** is a diagnostic tool used to differentiate between essential hypertension and pheochromocytoma in patients with borderline elevations of plasma catecholamines. [1] **1. Why 0.3 mg is correct:** Clonidine is a centrally acting $\alpha_2$-adrenergic agonist. In normal individuals or patients with essential hypertension, a single oral dose of **0.3 mg** suppresses the sympathetic nervous system, leading to a significant decrease in plasma norepinephrine levels (usually below 500 pg/mL). In patients with **pheochromocytoma**, catecholamine release is autonomous and independent of central sympathetic drive; therefore, norepinephrine levels remain elevated despite the administration of 0.3 mg of clonidine. **2. Why incorrect options are wrong:** * **10 mg:** This is a massive overdose. The typical daily dose for hypertension rarely exceeds 1.2–2.4 mg. * **100 mg and 200 mg:** These doses are lethal. They are several hundred times the therapeutic range and would cause severe cardiovascular collapse or profound CNS depression. **3. High-Yield Clinical Pearls for NEET-PG:** * **Indication:** Use this test only if baseline plasma metanephrines/catecholamines are equivocal (borderline high). * **Protocol:** Plasma catecholamines are measured at baseline and 3 hours after the 0.3 mg oral dose. * **Gold Standard:** While the suppression test is useful, the initial screening test of choice for pheochromocytoma remains **Plasma Free Metanephrines** (highest sensitivity) or **24-hour Urinary Fractionated Metanephrines**. [1] * **Rule of 10s:** Pheochromocytoma is 10% bilateral, 10% malignant, 10% extra-adrenal (paraganglioma), and 10% pediatric. [1]

Question 1

Alkaline phosphatase is elevated in all conditions below, except?

Accepted Answer

Hypophosphatemia

Answer

Rickets

Answer

Osteomalacia

Answer

Hypoparathyroidism

Question 2

All of the following are true about amiodarone-induced thyroid dysfunction except?

Accepted Answer

Hypothyroidism is more common in men.

Answer

Hyperthyroidism is common in iodine-deficient areas.

Answer

Amiodarone inhibits deiodinase activity.

Answer

Amiodarone therapy is associated with an initial reduction of serum T4 levels.

Question 3

Hypothyroidism is associated with which of the following clinical problems, except?

Accepted Answer

Thromboembolism

Answer

Menorrhagia

Answer

Early abortions

Answer

Galactorrhea

Question 4

A patient presented with headache and episodes of hypertension. In between the episodes, he was found to be normal. His urinary VMA levels were found to be raised. What is the most likely diagnosis?

Accepted Answer

Pheochromocytoma

Answer

Carcinoid syndrome

Answer

Small cell carcinoma

Answer

Addison's disease

Question 5

Which of the following is the drug of choice for the treatment of syndrome of inappropriate antidiuretic hormone secretion?

Accepted Answer

Demeclocycline

Answer

Vasopressin

Answer

Thiazide diuretics

Answer

Chloropropamide

Question 6

Which condition is associated with the "Rugger jersey" sign?

Accepted Answer

Multiple myeloma

Answer

Ankylosing spondylitis

Answer

Tuberculosis of the spine

Answer

Osteoarthritis

Question 7

Which of the following is the best intervention to reduce the incidence of macrovascular complications in type 2 diabetes?

Accepted Answer

Strict blood pressure control

Answer

HbA1c less than 6.5%

Answer

Urine microalbumin measurement

Answer

Fasting capillary blood glucose values below 180 mg/dL

Question 8

Which of the following is true about Type I diabetes mellitus?

Accepted Answer

Autoimmune disorder

Answer

Insulin non-dependent

Answer

Insulin does not improve the symptoms

Answer

Late age of onset

Question 9

Which of the following is NOT a sign of pituitary apoplexy?

Accepted Answer

Hypertension

Answer

Shock

Answer

Loss of consciousness

Answer

Headache

Question 10

What is the dose of clonidine used in the suppression test for pheochromocytoma?

Accepted Answer

0.3 mg

Answer

10 mg

Answer

100 mg

Answer

200 mg

Endocrinology — MCQs

Endocrinology — MCQs

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