Endocrinology Practice Questions

Q: What is the treatment of choice for a 52-year-old male with toxic adenoma?

Radioactive iodine. **Explanation:** Toxic Adenoma (Plummer’s Disease) is characterized by a single hyperfunctioning thyroid nodule that autonomously produces thyroid hormones, leading to the suppression of TSH and subsequent "shut down" of the surrounding normal thyroid tissue. **Why Radioactive Iodine (RAI) is the Correct Answer:** In patients over 40–45 years (like this 52-year-old male), **Radioactive Iodine ($I^{131}$)** is the treatment of choice. The underlying medical concept is the **"Selective Uptake"** principle: because the TSH is suppressed, the normal thyroid tissue is inactive and does not take up the iodine. Only the "hot" toxic nodule traps the $I^{131}$, leading to localized destruction of the adenoma while sparing the rest of the gland. This results in a very low risk of post-treatment hypothyroidism compared to Grave’s disease. **Analysis of Incorrect Options:** * **A. Surgical removal (Hemithyroidectomy):** While effective, surgery is generally reserved for younger patients (<40 years), very large nodules causing compressive symptoms, or when malignancy is suspected. * **B. Radiotherapy:** External beam radiation has no role in the management of benign toxic adenomas. * **D. Medical treatment:** Antithyroid drugs (Methimazole/PTU) are used only to achieve a euthyroid state before definitive therapy (RAI or Surgery). They are not a permanent cure because the nodule will resume hyperfunctioning once the medication is stopped. **NEET-PG High-Yield Pearls:** * **Investigation of Choice:** Radionuclide Thyroid Scan (shows a "Hot Nodule" with suppression of the rest of the gland). * **Treatment of Choice ( 40 years):** Radioactive Iodine ($I^{131}$). * **Toxic Multinodular Goiter (TMNG):** Also prefers RAI in elderly, but surgery (Total Thyroidectomy) if the goiter is large or retrosternal.

Q: A patient with an endocrine abnormality shows a 'hung up' reflex. Which of the following conditions causes a 'hung up' reflex?

Hypothyroidism. ### Explanation **Correct Answer: C. Hypothyroidism** The **'hung up' reflex** (also known as Woltman’s sign) refers to a delayed relaxation phase of the deep tendon reflexes, most commonly observed in the Achilles tendon (ankle jerk). **Underlying Pathophysiology:** In hypothyroidism, the slowed relaxation is not due to a defect in nerve conduction, but rather a **mechanical delay in the muscle fibers**. Low levels of thyroid hormone lead to: 1. Decreased activity of the **calcium-ATPase pump** (SERCA) in the sarcoplasmic reticulum, which slows the reuptake of calcium required for muscle relaxation. 2. Changes in myosin isoform expression and slowed ATP turnover. **Analysis of Incorrect Options:** * **A. Myxedema:** While myxedema is a severe form of hypothyroidism, the term "Hypothyroidism" (Option C) is the broader, standard clinical diagnosis associated with this sign [1]. In many exams, if both are present, the primary disease state is preferred. * **B. Hyperthyroidism:** This condition typically presents with **brisk or hyperreflexic** deep tendon reflexes due to increased neuromuscular excitability. * **D. Pheochromocytoma:** This catecholamine-secreting tumor causes hypertension and tachycardia; it does not typically affect the relaxation phase of reflexes [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Woltman’s Sign:** Specifically refers to the delayed relaxation in hypothyroidism. * **Differential Diagnosis for Delayed Relaxation:** Besides hypothyroidism, it can be seen in anorexia nervosa, hypothermia, diabetes mellitus (rarely), and with certain drugs like beta-blockers. * **Pendular Knee Jerk:** Contrast this with the "hung up" reflex; pendular jerks are characteristic of **cerebellar lesions**. * **Pseudomyotonia:** Another term sometimes used to describe the slow relaxation phase in hypothyroid patients.

Q: What is the cause of Cushing's disease?

ACTH-producing pituitary tumor. **Explanation:** The distinction between **Cushing’s Syndrome** and **Cushing’s Disease** is a frequent high-yield topic in NEET-PG. Cushing’s Syndrome is the broad clinical state resulting from chronic exposure to excessive glucocorticoids. **Cushing’s Disease** specifically refers to the subset of cases (approximately 70% of endogenous causes) where the hypercortisolism is caused by an **ACTH-secreting pituitary adenoma** (Option A). **Analysis of Options:** * **Option A (Correct):** Cushing’s Disease is defined by a pituitary microadenoma (usually <10mm) that secretes excess ACTH, leading to bilateral adrenal hyperplasia and elevated cortisol. * **Option B (Incorrect):** Adrenal tumors (adenomas or carcinomas) cause ACTH-independent Cushing’s syndrome. In these cases, ACTH levels are suppressed due to negative feedback. * **Option C (Incorrect):** Ectopic ACTH production (often from Small Cell Lung Cancer or Bronchial Carcinoid) causes Cushing’s syndrome, not "Disease." These patients often present with rapid onset, severe hypokalemia, and hyperpigmentation. * **Option D (Incorrect):** Adrenal hyperplasia is a *consequence* of excess ACTH (either pituitary or ectopic), not the primary cause of Cushing’s Disease itself. **High-Yield Clinical Pearls for NEET-PG:** 1. **Screening Test:** 24-hour urinary free cortisol or Low-Dose Dexamethasone Suppression Test (LDDST). 2. **Confirmatory/Localization:** High-Dose Dexamethasone Suppression Test (HDDST) will suppress cortisol in Cushing’s **Disease** but *not* in ectopic ACTH or adrenal tumors. 3. **Gold Standard for Localization:** Inferior Petrosal Sinus Sampling (IPSS) is used if MRI is inconclusive to differentiate pituitary vs. ectopic sources. 4. **Treatment of Choice:** Transsphenoidal Surgery (TSS).

Q: A 45-year-old man, a known case of chronic renal failure, develops rugger jersey spine. What is the probable cause?

Secondary hyperparathyroidism. **Explanation:** The **Rugger Jersey Spine** is a classic radiological sign pathognomonic for **Renal Osteodystrophy**, specifically caused by **Secondary Hyperparathyroidism**. **1. Why Secondary Hyperparathyroidism is correct:** In chronic renal failure (CRF), the kidneys fail to excrete phosphate and cannot convert Vitamin D to its active form (1,25-dihydroxyvitamin D). This leads to hyperphosphatemia and hypocalcemia, which chronically stimulate the parathyroid glands [3]. The resulting excess Parathyroid Hormone (PTH) increases osteoclastic activity [1]. Radiologically, this manifests as alternating bands of sclerotic (dense) bone at the superior endplates of the vertebrae and radiolucent (decalcified) bone in the center, mimicking the stripes on a British rugby jersey. **2. Why other options are incorrect:** * **Aluminium intoxication:** Previously common due to aluminium-containing phosphate binders, it typically causes **Adynamic Bone Disease** or osteomalacia [1], not the sclerotic bands seen in rugger jersey spine. * **Osteoporosis:** Characterized by a generalized decrease in bone mass. Radiologically, it shows "codfish vertebrae" or wedge fractures, but not the distinct banded sclerosis [2]. * **Osteomalacia:** Involves defective mineralization of the bone matrix [4]. While it occurs in CRF, its hallmark radiological features are **Looser’s zones** (pseudofractures), not vertebral sclerosis. **Clinical Pearls for NEET-PG:** * **Rugger Jersey Spine:** Secondary Hyperparathyroidism (Renal Osteodystrophy). * **Salt and Pepper Skull:** Another classic sign of Hyperparathyroidism (granular decalcification). * **Brown Tumors:** Osteoclastoma-like lesions found in primary or secondary hyperparathyroidism. * **Ivory Vertebrae:** Differential includes Hodgkin’s Lymphoma, Paget’s disease, and Metastatic Prostatic Carcinoma (distinct from Rugger Jersey as the entire vertebra is dense).

Q: Carcinoid syndrome is associated with all except?

VMA in urine. **Explanation:** Carcinoid syndrome is caused by the systemic release of vasoactive substances (primarily **Serotonin**) from neuroendocrine tumors [1]. **Why "VMA in urine" is the correct answer:** Vanillylmandelic acid (VMA) is the end-metabolite of catecholamines (Epinephrine and Norepinephrine). Elevated urinary VMA is a diagnostic marker for **Pheochromocytoma**, not carcinoid syndrome. The gold-standard biochemical marker for Carcinoid syndrome is **5-HIAA (5-Hydroxyindoleacetic acid)**, which is the urinary metabolite of Serotonin. **Analysis of other options:** * **Flushing of skin:** This is the most common clinical feature (85% of cases), caused by the release of kinins and histamine [1]. * **Skin lesions like pellagra:** Carcinoid tumors divert up to 60% of the body's dietary **Tryptophan** to produce Serotonin. This leads to a deficiency in Niacin (Vitamin B3) synthesis, resulting in pellagra-like symptoms (Dermatitis, Diarrhea, Dementia) [2]. * **Bronchospasm:** Occurs in about 15% of patients due to the release of histamine and serotonin, manifesting as wheezing. **High-Yield Clinical Pearls for NEET-PG:** * **Primary Site:** Most common site for carcinoid tumors is the **Ileum** (small intestine). * **The Rule of Metastasis:** Carcinoid syndrome usually occurs only after the tumor has metastasized to the **liver**, as the liver otherwise metabolizes the bioactive substances via the portal circulation [1]. * **Cardiac Involvement:** Right-sided heart failure (Tricuspid regurgitation/Pulmonary stenosis) is common. Left-sided lesions are rare because the lungs metabolize serotonin. * **Treatment:** **Octreotide** (Somatostatin analogue) is the drug of choice to manage symptoms.

Q: What is the most common organ involved in Multiple Endocrine Neoplasia type 1 (MEN-1)?

Parathyroid. **Explanation:** **Multiple Endocrine Neoplasia type 1 (MEN-1)**, also known as Wermer’s syndrome, is an autosomal dominant disorder caused by a mutation in the *MEN1* gene (encoding the protein Menin). It is classically characterized by the "3 Ps": **P**arathyroid, **P**ancreas, and **P**ituitary. 1. **Why Parathyroid is correct:** Primary Hyperparathyroidism (PHPT) is the **most common** and often the **earliest** clinical manifestation of MEN-1, occurring in over 95% of patients by age 40. Unlike sporadic cases, parathyroid involvement in MEN-1 typically presents as multiglandular hyperplasia rather than a single adenoma. 2. **Why other options are incorrect:** * **Thyroid:** While thyroid adenomas or goiters can occasionally be seen in MEN-1 patients, they are not a defining feature. Medullary thyroid carcinoma is a hallmark of **MEN-2**, not MEN-1. * **Adrenal:** Adrenal cortical tumors (usually non-functional) occur in about 20–40% of MEN-1 cases, making them less common than parathyroid involvement. * **Testis:** Testicular tumors are not a standard component of the MEN-1 clinical triad. **High-Yield Clinical Pearls for NEET-PG:** * **The 3 Ps of MEN-1:** Parathyroid (95%), Pancreatic Islet cells (e.g., Gastrinoma, Insulinoma - 40-70%), and Anterior Pituitary (e.g., Prolactinoma - 30-40%). * **Gastrinoma** (Zollinger-Ellison Syndrome) is the most common functional enteropancreatic neuroendocrine tumor in MEN-1. * **Screening:** If a patient presents with recurrent peptic ulcers and hypercalcemia, always suspect MEN-1. * **MEN-2A:** Medullary Thyroid CA + Pheochromocytoma + Parathyroid. * **MEN-2B:** Medullary Thyroid CA + Pheochromocytoma + Mucosal Neuromas/Marfanoid habitus.

Q: Which of the following statements is FALSE about Type I Diabetes Mellitus?

Obesity is a common feature.. **Explanation:** Type 1 Diabetes Mellitus (T1DM) is characterized by an absolute deficiency of insulin due to the autoimmune destruction of pancreatic beta cells. **Why Option B is the correct answer (False statement):** Unlike Type 2 Diabetes Mellitus (T2DM), where insulin resistance is strongly linked to adiposity, **obesity is not a common feature of T1DM** [1]. In fact, patients with T1DM typically present with **weight loss** at the time of diagnosis [2]. This occurs because the lack of insulin leads to a catabolic state, causing the breakdown of fat and muscle stores to provide energy [2]. **Analysis of other options:** * **Option A (True):** Due to the absolute lack of insulin, patients are highly prone to **Diabetic Ketoacidosis (DKA)** [1]. Without insulin, lipolysis is unchecked, leading to the production of ketone bodies [2]. * **Option C (True):** The hallmark of T1DM is **reduced or absent serum insulin** and C-peptide levels, resulting from the destruction of >90% of beta-cell mass. * **Option D (True):** Genetic susceptibility is strongly linked to the **HLA region on Chromosome 6p21** [1]. Specifically, **HLA-DR3 and HLA-DR4** alleles are found in approximately 95% of T1DM patients. **High-Yield NEET-PG Pearls:** * **Most common age of onset:** Bimodal peaks at 4–6 years and 10–14 years. * **Autoantibodies:** Anti-GAD65 (most persistent), Anti-IA2, and Zinc Transporter 8 (ZnT8) antibodies are key diagnostic markers [1]. * **Honeymoon Phase:** A temporary period after starting insulin where remaining beta cells function briefly, reducing exogenous insulin requirements. * **Association:** T1DM is often associated with other autoimmune conditions like Hashimoto’s thyroiditis and Celiac disease [3].

Q: Which of the following tests is best for diagnosing carcinoid tumor?

24-hour urinary 5-hydroxyindoleacetic acid (HIAA). ### Explanation **Correct Option: A. 24-hour urinary 5-hydroxyindoleacetic acid (5-HIAA)** **Medical Concept:** Carcinoid tumors are neuroendocrine tumors that frequently secrete excessive amounts of **serotonin (5-hydroxytryptamine)**. Serotonin is metabolized by the enzyme monoamine oxidase (MAO) and aldehyde dehydrogenase into **5-hydroxyindoleacetic acid (5-HIAA)**, which is then excreted in the urine. Measuring 5-HIAA in a 24-hour urine collection is the gold-standard biochemical screening test for diagnosing carcinoid syndrome. It has high specificity (approx. 90%) for the condition. **Analysis of Incorrect Options:** * **B, C, and D (Catecholamines, VMA, and Metanephrines):** These are metabolites of epinephrine and norepinephrine. They are used in the diagnostic workup of **Pheochromocytoma** and **Neuroblastoma**, not carcinoid tumors. Metanephrines (Option D) are currently considered the most sensitive screening test for Pheochromocytoma. **NEET-PG High-Yield Pearls:** * **Dietary Interference:** Patients must avoid serotonin-rich foods (bananas, walnuts, pineapples, avocados, tomatoes) for 24–48 hours before the 5-HIAA test to prevent false-positive results. * **Localization:** Once biochemically confirmed, the most sensitive imaging for localization is **Somatostatin Receptor Scintigraphy (OctreoScan)** or **68Ga-DOTATATE PET/CT** [1]. * **Clinical Triad:** Carcinoid syndrome (usually occurring with liver metastasis) presents with **flushing, diarrhea, and right-sided valvular heart disease** (tricuspid regurgitation/pulmonary stenosis) [1]. * **Chromogranin A:** This is a non-specific but useful serum marker for monitoring tumor burden and recurrence in neuroendocrine tumors [2].

Q: A 62-year-old Type 2 diabetic patient presents with complaints of malaise, myalgias, respiratory distress, and increased somnolence. Laboratory examination reveals an anion gap of 26mmol/L, HCO3- of 17 mmol/L, and an arterial blood pH of 7.27. Suspecting lactic acidosis, which of the following medications is the patient most likely receiving?

Metformin. **Explanation:** The patient presents with **Metformin-Associated Lactic Acidosis (MALA)**, characterized by a high anion gap metabolic acidosis (HAGMA), low pH, and non-specific symptoms like malaise and respiratory distress (Kussmaul breathing) [2]. **1. Why Metformin is correct:** Metformin, a biguanide, inhibits mitochondrial glycerophosphate dehydrogenase and the mitochondrial respiratory chain complex I. This leads to a shift toward anaerobic metabolism, increasing the conversion of pyruvate to **lactate** [2]. While rare, MALA typically occurs in patients with predisposing factors such as renal impairment, hepatic failure, or severe sepsis, where lactate clearance is reduced [2]. The laboratory findings (pH 7.27, HCO3- 17, and Anion Gap 26) are classic for this condition [1]. **2. Why other options are incorrect:** * **Glyburide:** A second-generation sulfonylurea. Its primary side effect is **hypoglycemia** and weight gain; it does not cause lactic acidosis. * **Miglitol:** An alpha-glucosidase inhibitor that acts locally in the GI tract to delay carbohydrate absorption. Its side effects are primarily gastrointestinal (flatulence, diarrhea). * **Glucagon:** A hormone used to treat severe hypoglycemia. It promotes glycogenolysis and gluconeogenesis, which would typically oppose the metabolic state of lactic acidosis. **Clinical Pearls for NEET-PG:** * **MALA Risk Factor:** The most significant risk factor for MALA is **renal insufficiency**. Metformin is generally contraindicated if the eGFR is <30 mL/min/1.73m². * **Management:** The treatment of choice for severe MALA with renal failure is **Hemodialysis**, which removes both metformin and lactate. * **Contrast Media:** Metformin should be withheld for 48 hours after procedures involving IV iodinated contrast to prevent acute kidney injury-induced MALA.

Q: Which tumor follows the "rule of 10"?

Pheochromocytoma. **Explanation:** **Pheochromocytoma** is a catecholamine-secreting tumor arising from the chromaffin cells of the adrenal medulla. It is classically associated with the **"Rule of 10,"** which serves as a high-yield clinical mnemonic for its epidemiological characteristics: * **10% Extra-adrenal:** Occur in the Paraganglia (Organ of Zuckerkandl). * **10% Bilateral:** Often associated with familial syndromes. * **10% Malignant:** Most are benign; malignancy is defined by metastasis, not histology. * **10% Pediatric:** Though primarily an adult diagnosis. * **10% Familial:** (Note: Modern genetics suggests this is now closer to 30-40% involving RET, VHL, and NF1 genes). * **10% Normotensive:** While most present with paroxysmal hypertension. **Analysis of Incorrect Options:** * **B. Oncocytoma:** A benign renal tumor characterized by a "central stellate scar" on imaging. It does not follow a specific "rule of 10." * **C. Lymphoma:** A hematological malignancy of the lymphoid system. Its classification (Hodgkin vs. Non-Hodgkin) and staging (Ann Arbor) are key, but it lacks this specific numerical rule. * **D. Renal Cell Carcinoma (RCC):** Known for the "classic triad" (hematuria, flank pain, palpable mass) and its association with VHL syndrome, but it does not follow the rule of 10. **Clinical Pearls for NEET-PG:** * **Diagnosis:** Best initial screening test is **24-hour urinary fractionated metanephrines** or plasma free metanephrines. * **Management:** Always give **Alpha-blockers first** (e.g., Phenoxybenzamine) followed by Beta-blockers to avoid a hypertensive crisis (unopposed alpha stimulation). * **Histology:** Look for the **"Zellballen" pattern** (nested clusters of cells).

Question 1

What is the treatment of choice for a 52-year-old male with toxic adenoma?

Accepted Answer

Radioactive iodine

Answer

Surgical removal of the adenoma

Answer

Radiotherapy

Answer

Medical treatment

Question 2

A patient with an endocrine abnormality shows a 'hung up' reflex. Which of the following conditions causes a 'hung up' reflex?

Accepted Answer

Hypothyroidism

Answer

Myxedema

Answer

Hyperthyroidism

Answer

Pheochromocytoma

Question 3

What is the cause of Cushing's disease?

Accepted Answer

ACTH-producing pituitary tumor

Answer

Adrenal tumor

Answer

Ectopic production of ACTH

Answer

Adrenal hyperplasia

Question 4

A 45-year-old man, a known case of chronic renal failure, develops rugger jersey spine. What is the probable cause?

Accepted Answer

Secondary hyperparathyroidism

Answer

Aluminium intoxication

Answer

Osteoporosis

Answer

Osteomalacia

Question 5

Carcinoid syndrome is associated with all except?

Accepted Answer

VMA in urine

Answer

Flushing of skin

Answer

Skin lesions like pellagra

Answer

Bronchospasm

Question 6

What is the most common organ involved in Multiple Endocrine Neoplasia type 1 (MEN-1)?

Accepted Answer

Parathyroid

Answer

Thyroid

Answer

Adrenal

Answer

Testis

Question 7

Which of the following statements is FALSE about Type I Diabetes Mellitus?

Accepted Answer

Obesity is a common feature.

Answer

Patients are prone to Diabetic Ketoacidosis (DKA).

Answer

There is reduced serum insulin level.

Answer

Susceptibility genes are located on Chromosome 6.

Question 8

Which of the following tests is best for diagnosing carcinoid tumor?

Accepted Answer

24-hour urinary 5-hydroxyindoleacetic acid (HIAA)

Answer

24-hour urinary catecholamines

Answer

24-hour urinary vanillylmandelic acid (VMA)

Answer

24-hour urinary metanephrine levels

Question 9

A 62-year-old Type 2 diabetic patient presents with complaints of malaise, myalgias, respiratory distress, and increased somnolence. Laboratory examination reveals an anion gap of 26mmol/L, HCO3- of 17 mmol/L, and an arterial blood pH of 7.27. Suspecting lactic acidosis, which of the following medications is the patient most likely receiving?

Accepted Answer

Metformin

Answer

Glucagon

Answer

Glyburide

Answer

Miglitol

Question 10

Which tumor follows the "rule of 10"?

Accepted Answer

Pheochromocytoma

Answer

Oncocytoma

Answer

Lymphoma

Answer

Renal cell carcinoma

Endocrinology — MCQs

Endocrinology — MCQs

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