Endocrinology Practice Questions

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: Gynaecomastia is seen in all except?

Hypothyroidism. **Explanation:** Gynecomastia is the benign proliferation of glandular breast tissue in males, primarily caused by an imbalance between estrogen and androgen action. **Why Hypothyroidism is the Correct Answer:** **Hyperthyroidism**, not hypothyroidism, is a classic cause of gynecomastia. In hyperthyroidism, increased thyroid hormones stimulate the production of **Sex Hormone-Binding Globulin (SHBG)**. SHBG has a higher affinity for testosterone than estrogen; thus, it binds free testosterone, decreasing the testosterone-to-estrogen ratio. Conversely, hypothyroidism is generally not associated with gynecomastia. **Analysis of Other Options:** * **Spironolactone:** This is the most common drug-induced cause [1]. It acts as a competitive antagonist at the androgen receptor and inhibits testosterone synthesis. * **Klinefelter Syndrome (47, XXY):** This is the most common congenital cause. It presents with primary testicular failure (low testosterone) and elevated gonadotropins. The increased LH stimulates aromatase activity in Leydig cells, leading to increased conversion of testosterone to estradiol. * **Cirrhotic Liver Disease:** Liver failure leads to gynecomastia via two mechanisms: decreased degradation of androstenedione (which is peripherally converted to estrogen) and increased SHBG production by the liver, which lowers free testosterone levels. **High-Yield Clinical Pearls for NEET-PG:** * **Physiological Gynecomastia:** Seen in neonates, during puberty (most common), and in the elderly [1]. * **Drug Mnemonic (DISCO):** **D**igoxin, **I**soniazid, **S**pironolactone, **C**imetidine, **O**estrogens/Ketoconazole [1]. * **Refeeding Syndrome:** Can cause "refeeding gynecomastia" due to a rebound in pituitary gonadotropin production after malnutrition. * **Testicular Tumors:** Leydig cell tumors and hCG-secreting germ cell tumors are important pathological differentials [1].

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: A 24-year-old woman presents 6 months after delivery for evaluation of fatigue. She notes cold intolerance and mild constipation. She recalls having a tremor and mild palpitations for a few weeks, beginning 3 months after delivery. On examination, her BP is 126/84 and her pulse rate is 56. The thyroid gland is two times normal in size and nontender. Laboratory studies reveal a free T4 level of 0.7 ng/mL (normal 0.9-2.4) and an elevated thyroid-stimulating hormone (TSH) at 22 microU/mL (normal 0.4-4). What is the likely course of her illness?

Recovery with euthyroidism. ### Explanation The clinical presentation is classic for **Postpartum Thyroiditis (PPT)**, a variant of silent (painless) lymphocytic thyroiditis occurring within one year of delivery. **1. Why Option C is Correct:** Postpartum thyroiditis typically follows a **triphasic course**: * **Thyrotoxic phase (2–4 months postpartum):** Caused by the release of preformed thyroid hormone (destructive thyroiditis). This explains the patient's initial tremors and palpitations [1]. * **Hypothyroid phase (3–8 months postpartum):** As hormone stores are depleted, the patient develops symptoms like fatigue, cold intolerance, and constipation, with labs showing low T4 and high TSH (as seen in this patient) [1]. * **Recovery phase:** In **70–80% of cases**, thyroid function returns to **euthyroidism** spontaneously within a few months. **2. Why the Other Options are Incorrect:** * **Option A:** While 20–30% of patients may develop permanent hypothyroidism, the majority recover. Permanent replacement is not the "likely" course unless high titers of anti-TPO antibodies persist [1]. * **Option B:** Methimazole is ineffective in PPT because the hyperthyroidism is due to "leakage" of hormone, not increased synthesis [1]. * **Option D:** PPT does not cause permanent infertility, though the hypothyroid phase may cause temporary menstrual irregularities. **Clinical Pearls for NEET-PG:** * **Hallmark:** PPT is **nontender** (distinguishing it from De Quervain’s/Subacute thyroiditis). * **Diagnosis:** Low radioactive iodine uptake (RAIU) during the thyrotoxic phase [1]. * **Antibodies:** Anti-TPO antibodies are present in 60–80% of cases. * **Management:** Propanolol for the thyrotoxic phase; Levothyroxine for the hypothyroid phase (usually for 6–12 months, then tapered to check for recovery) [1].

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).

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

Hypoparathyroidism. **Explanation:** **Hypoparathyroidism** is the correct answer because it is characterized by a deficiency of Parathyroid Hormone (PTH). PTH is a major regulator of bone remodeling; it stimulates both osteoblastic and osteoclastic activity. In its absence, bone turnover is significantly reduced, leading to an **increase in bone mineral density (BMD)** rather than a decrease. Therefore, it is not associated with osteoporosis. **Analysis of Incorrect Options:** * **Immobilization:** Lack of mechanical loading leads to "disuse osteoporosis." According to Wolff’s Law, bone adapts to the loads under which it is placed. Immobilization triggers rapid bone resorption by osteoclasts. * **Thyrotoxicosis:** Excess thyroid hormone (T3/T4) shortens the bone remodeling cycle, leading to a high-turnover state where bone resorption exceeds formation, resulting in secondary osteoporosis. * **Turner’s Syndrome:** This condition is associated with primary ovarian failure (hypogonadism). Estrogen deficiency leads to increased cytokine activity (IL-1, IL-6, TNF-α), which stimulates osteoclasts, causing significant bone loss. **High-Yield Clinical Pearls for NEET-PG:** * **Hyperparathyroidism** (specifically primary) is associated with osteoporosis and the classic "Salt and Pepper" skull appearance. * **Drug-induced Osteoporosis:** Long-term use of Glucocorticoids (most common cause), Heparin, and Phenytoin are frequent NEET-PG topics. * **Gold Standard Investigation:** DEXA Scan (Dual-Energy X-ray Absorptiometry). A **T-score of ≤ -2.5** defines osteoporosis. * **Bisphosphonates** (e.g., Alendronate) are the first-line treatment; they act by inhibiting osteoclast-mediated bone resorption.

Question 1

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 2

Gynaecomastia is seen in all except?

Accepted Answer

Hypothyroidism

Answer

Spironolactone

Answer

Klinefelters syndrome

Answer

Cirrhotic liver diseases

Question 3

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 4

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 5

Which of the following endocrine disorders is a result of molecular mimicry?

Accepted Answer

Hashimoto's thyroiditis

Answer

Addison's disease

Answer

Diabetes Mellitus

Answer

Hypoparathyroidism

Question 6

A 24-year-old woman presents 6 months after delivery for evaluation of fatigue. She notes cold intolerance and mild constipation. She recalls having a tremor and mild palpitations for a few weeks, beginning 3 months after delivery. On examination, her BP is 126/84 and her pulse rate is 56. The thyroid gland is two times normal in size and nontender. Laboratory studies reveal a free T4 level of 0.7 ng/mL (normal 0.9-2.4) and an elevated thyroid-stimulating hormone (TSH) at 22 microU/mL (normal 0.4-4). What is the likely course of her illness?

Accepted Answer

Recovery with euthyroidism

Answer

Permanent hypothyroidism requiring lifelong replacement therapy

Answer

Eventual hyperthyroidism requiring methimazole therapy

Answer

Infertility

Question 7

Which tumor follows the "rule of 10"?

Accepted Answer

Pheochromocytoma

Answer

Oncocytoma

Answer

Lymphoma

Answer

Renal cell carcinoma

Question 8

A 65-year-old woman with a history of multinodular goiter complains of increasing nervousness, insomnia, and heart palpitations. She has lost 9 kg (20 lb) over the past 6 months. Physical examination reveals a diffusely enlarged thyroid. There is no evidence of exophthalmos. Laboratory studies show elevated serum levels of T3 and T4. Serologic tests for antithyroid antibodies are negative. Which of the following is an important complication of this patient's endocrinopathy?

Accepted Answer

Cardiac arrhythmia

Answer

Autoimmune hepatitis

Answer

Follicular carcinoma of the thyroid

Answer

Medullary carcinoma of the thyroid

Question 9

Which of the following conditions is not associated with osteoporosis?

Accepted Answer

Hypoparathyroidism

Answer

Immobilization

Answer

Thyrotoxicosis

Answer

Turner's syndrome

Question 10

Which of the following organs are not affected in autoimmune polyglandular syndrome type 2?

Accepted Answer

Adrenal

Answer

Parathyroid

Answer

Thyroid

Answer

Pancreas

Endocrinology — MCQs

Endocrinology — MCQs

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