Endocrinology Practice Questions

Q: Which of the following statements regarding insulin resistance in diabetic patients is FALSE?

It is more common with huminsulin.. Explanation: 1. Why Option A is the correct (False) statement: Insulin resistance due to antibody formation is significantly less common with human insulin (Huminsulin) compared to older animal-derived insulins (bovine or porcine) [2]. Human insulin is produced via recombinant DNA technology and is identical to endogenous human insulin, making it far less immunogenic. Animal insulins differ by one (porcine) or three (bovine) amino acids, which triggers the production of anti-insulin antibodies (IgG), leading to immune-mediated insulin resistance [2]. 2. Analysis of other options: * Option B (True): Infections trigger the release of counter-regulatory hormones like cortisol, glucagon, and catecholamines. These hormones induce a state of acute insulin resistance and hyperglycemia [3]. * Option C (True): High titers of circulating anti-insulin IgG antibodies can neutralize injected insulin, preventing it from binding to receptors [2]. This is the classic definition of "immune insulin resistance." * Option D (True): In severe cases of immune-mediated insulin resistance (where antibody titers are very high), glucocorticoids are used therapeutically to suppress the immune system and reduce antibody production, thereby restoring insulin sensitivity [3]. 3. NEET-PG High-Yield Pearls: * Definition: Clinical insulin resistance is defined as a daily requirement of >200 units of insulin in the absence of ketoacidosis or infection. * Most Immunogenic Insulin: Bovine insulin (highest amino acid variance). * Least Immunogenic Insulin: Human insulin and insulin analogues (Lispro, Aspart). * Acanthosis Nigricans: A key clinical marker of non-immune insulin resistance (Type 2 DM/Metabolic Syndrome) [1].

Q: What is the drug of choice in an 80-year-old patient presenting with hyperglycemia and ketoacidosis?

Short acting insulin. The clinical presentation of hyperglycemia combined with ketoacidosis indicates a diagnosis of **Diabetic Ketoacidosis (DKA)** [1]. DKA is a medical emergency characterized by an absolute or relative deficiency of insulin, leading to hyperglycemia, ketonemia, and metabolic acidosis [4]. **Why Short-Acting Insulin is Correct:** The cornerstone of DKA management, regardless of the patient's age, is **Regular (Short-acting) Insulin** administered via a continuous intravenous infusion [2]. Short-acting insulin is preferred because: 1. **Rapid Onset:** It works immediately to inhibit lipolysis and ketogenesis. 2. **Titratability:** Its short half-life allows for precise dose adjustments based on hourly blood glucose and anion gap monitoring. 3. **Safety:** In an 80-year-old patient who may have underlying renal or cardiac comorbidities, the ability to quickly stop the insulin effect if hypoglycemia occurs is vital [3]. **Why Other Options are Incorrect:** * **Oral Hypoglycemic Drugs (A & C):** These are contraindicated in DKA. They are insufficient to reverse ketosis and cannot be used in acute, life-threatening metabolic crises. * **Intermediate-Acting Insulin (B & C):** Drugs like NPH have a delayed onset and a prolonged peak. They do not allow for the rapid titration required to manage the dynamic shifts in electrolytes and glucose seen during DKA treatment. **NEET-PG High-Yield Pearls:** * **Standard Protocol:** Start with an IV bolus of 0.1 U/kg, followed by a continuous infusion of 0.1 U/kg/hr. * **The Goal:** The primary goal in DKA is to **close the anion gap** (stop ketosis), not just normalize blood glucose [2]. * **Potassium Warning:** Never start insulin if serum potassium is **<3.3 mEq/L**, as insulin will shift potassium intracellularly, potentially causing fatal arrhythmias [5]. * **Fluid of Choice:** Initial resuscitation should always begin with **0.9% Normal Saline** [1].

Q: Monogenic transmission of diabetes mellitus occurs in which of the following conditions?

Maturity Onset Diabetes of the Young (MODY). **Explanation:** The correct answer is **Maturity Onset Diabetes of the Young (MODY)**. **1. Why MODY is correct:** MODY is a classic example of **monogenic diabetes**, meaning it is caused by a mutation in a **single gene**. It follows an **autosomal dominant** inheritance pattern. Unlike Type 1 or Type 2 diabetes, which are polygenic (involving multiple genes and environmental factors), MODY results from primary defects in beta-cell function. The most common subtypes involve mutations in the *HNF1A* gene (MODY 3) and the *Glucokinase* gene (MODY 2). **2. Why other options are incorrect:** * **IDDM (Type 1 DM):** This is a **polygenic** autoimmune disorder. While there is a genetic predisposition (associated with HLA-DR3 and DR4), it requires environmental triggers and involves the destruction of beta cells by multiple antibodies. * **NIDDM (Type 2 DM):** This is also **polygenic** and multifactorial. It involves a complex interplay between numerous susceptibility genes, insulin resistance, and lifestyle factors (obesity). * **LADA:** Often called "Type 1.5 diabetes," LADA is an autoimmune form of diabetes in adults. Like Type 1 DM, it is **polygenic** and characterized by the presence of autoantibodies (e.g., anti-GAD). **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad of MODY:** (1) Early onset (usually <25 years), (2) Non-ketotic diabetes, and (3) Autosomal dominant family history (3 generations). * **MODY 2 (Glucokinase mutation):** Usually presents with mild, stable fasting hyperglycemia; often requires no treatment except during pregnancy. * **MODY 3 (HNF1A):** The most common form; these patients are highly sensitive to **Sulfonylureas**. * **Neonatal Diabetes:** Another monogenic form (presents <6 months of age), often due to *KCNJ11* mutations.

Q: Pheochromocytoma may be associated with which of the following?

Medullary carcinoma of the thyroid. ### Explanation **1. Why Medullary Carcinoma of the Thyroid (MTC) is Correct:** Pheochromocytoma is a key component of **Multiple Endocrine Neoplasia (MEN) Type 2 syndromes**, which are inherited in an autosomal dominant fashion due to mutations in the **RET proto-oncogene**. * **MEN 2A (Sipple Syndrome):** Characterized by Medullary Thyroid Carcinoma (100%), Pheochromocytoma (50%), and Parathyroid Hyperplasia (20%). * **MEN 2B:** Characterized by Medullary Thyroid Carcinoma, Pheochromocytoma, and mucosal neuromas/marfanoid habitus. In both syndromes, MTC is the most common manifestation, arising from the parafollicular C-cells that secrete calcitonin. **2. Why the Other Options are Incorrect:** * **Options B, C, and D:** Papillary, Follicular, and Anaplastic carcinomas are all derived from **thyroid follicular cells**. These are considered "sporadic" or related to radiation/iodine deficiency and are **not** associated with the RET mutations found in MEN syndromes. While Papillary carcinoma is the most common thyroid cancer overall, it has no syndromic link to Pheochromocytoma. **3. High-Yield Clinical Pearls for NEET-PG:** * **Rule of 10s for Pheochromocytoma:** 10% bilateral, 10% malignant, 10% extra-adrenal (Paraganglioma), and 10% familial (though modern genetics suggest up to 30-40% are familial). * **Surgical Sequence:** In a patient with both MTC and Pheochromocytoma, **always resect the Pheochromocytoma first** to prevent a lethal hypertensive crisis during thyroid surgery. * **Screening:** Patients with MTC should be screened for RET mutations and urinary catecholamines/metanephrines. * **Biomarker:** Calcitonin is the tumor marker for MTC.

Q: Which of the following statements about Cushing's syndrome is true?

ACTH secretion is the commonest cause.. Cushing’s syndrome refers to the clinical state of chronic glucocorticoid excess. The most common cause of **endogenous** Cushing’s syndrome is **ACTH-dependent** disease (approx. 80%), specifically a pituitary adenoma (Cushing’s Disease). [1] When considering all causes, including exogenous sources, iatrogenic administration of glucocorticoids is the overall most common cause. [1] However, among the pathological endogenous options provided, ACTH hypersecretion (primarily pituitary) is the leading etiology. [4] **2. Why the Other Options are Incorrect:** * **Option A:** In Cushing’s syndrome, the normal negative feedback loop is disrupted. Therefore, **low-dose** (1 mg or 2 mg) dexamethasone **fails to suppress** cortisol secretion. [3] Suppression with low-dose dexamethasone is the normal physiological response used to rule out the syndrome. * **Option B:** Adrenal **adenomas** are significantly more common than adrenal carcinomas. Adrenal carcinomas are rare, though they often present with more severe, rapid-onset virilization and hypercortisolism. [1] * **Option C:** In Cushing’s Disease (pituitary cause), the majority of cases (>90%) are caused by **microadenomas**, which are typically **less than 1 cm** (often 1 cm) are rare in this context. **Clinical Pearls for NEET-PG:** * **Screening Tests:** 24-hour urinary free cortisol, Late-night salivary cortisol, or Low-dose dexamethasone suppression test (LDDST). [3] * **High-dose Dexamethasone Test (HDDST):** Used to differentiate Pituitary (suppresses by >50%) from Ectopic ACTH (does not suppress). [2] * **Hyperpigmentation:** Seen only in ACTH-dependent causes (Pituitary or Ectopic) due to the co-secretion of Melanocyte-Stimulating Hormone (MSH). * **Hypokalemic Metabolic Alkalosis:** Highly suggestive of **Ectopic ACTH** secretion (e.g., Small Cell Lung Cancer).

Q: Which of the following statements regarding SIADH is FALSE?

Vaptans are new FDA-approved drugs for its treatment.. In SIADH (Syndrome of Inappropriate Antidiuretic Hormone), excessive ADH leads to water retention and dilutional hyponatremia [1]. **Explanation of the Correct Answer:** **Option C is FALSE** because Vaptans (Vasopressin receptor antagonists like Tolvaptan and Conivaptan) are indeed FDA-approved and effective for treating SIADH. In the context of this specific question (often sourced from older medical literature or specific exam patterns), it is considered the "false" statement because the standard first-line treatment remains **fluid restriction** [2]. While Vaptans are used, they are not the primary or "new" standard for all cases; however, technically, they are approved. *Note: In some versions of this question, Option B is considered the answer because urine sodium in SIADH is typically **high** (>20-40 mEq/L) due to natriuresis.* **Analysis of Other Options:** * **Option A:** True. SIADH is a classic cause of **euvolemic hyponatremia**, where serum sodium is characteristically 20 mEq/L) due to the body's attempt to excrete sodium to maintain euvolemia. * **Option D:** True. The **Water Loading Test** was historically used for diagnosis; patients with SIADH cannot excrete a water load normally [1]. However, it is rarely performed today due to the risk of worsening hyponatremia. **NEET-PG High-Yield Pearls:** 1. **Diagnostic Criteria:** Hyponatremia, low serum osmolality ( 100 mOsm/kg). 2. **Urine Sodium:** Must be >20-40 mEq/L (High) with normal salt intake. 3. **Treatment:** Fluid restriction is 1st line [2]. For severe symptoms, use **3% Hypertonic Saline**. 4. **Complication:** Rapid correction of sodium can lead to **Osmotic Demyelination Syndrome (Central Pontine Myelinolysis)** [2]. Limit correction to <8-10 mEq/L in 24 hours [2].

Question 1

Which of the following statements regarding insulin resistance in diabetic patients is FALSE?

Accepted Answer

It is more common with huminsulin.

Answer

It may occur in the presence of infections.

Answer

It may be due to antibodies to insulin.

Answer

Use of glucocorticoids may be useful in severe cases.

Question 2

A 33-year-old woman has experienced episodes of fatigue, pleural effusion, pericardial effusion, carpal tunnel syndrome, and macrocytic anemia. What is the best test for diagnosis?

Accepted Answer

Assay for thyroid hormones

Answer

Anti-beta 2 phospholipid antibodies

Answer

Anti-smith antibody

Answer

Antinuclear antibody

Question 3

What is the drug of choice in an 80-year-old patient presenting with hyperglycemia and ketoacidosis?

Accepted Answer

Short acting insulin

Answer

Oral hypoglycemic drugs

Answer

Intermediate acting insulin

Answer

Oral drug with intermediate acting insulin

Question 4

Monogenic transmission of diabetes mellitus occurs in which of the following conditions?

Accepted Answer

Maturity Onset Diabetes of the Young (MODY)

Answer

Insulin Dependent Diabetes Mellitus (IDDM)

Answer

Non-insulin Dependent Diabetes Mellitus (NIDDM)

Answer

Latent Autoimmune Diabetes in Adults (LADA)

Question 5

Thyrotoxicosis can be differentiated from anxiety neurosis clinically by?

Accepted Answer

Sleeping pulse rate

Answer

Tachycardia

Answer

Moist hands

Answer

Ankle's jerk

Question 6

Which complication of diabetes mellitus cannot be prevented by strict control of blood sugar levels?

Accepted Answer

Macular edema

Answer

Amyotrophy

Answer

Nerve conductivity

Answer

Microalbuminuria

Question 7

Pheochromocytoma may be associated with which of the following?

Accepted Answer

Medullary carcinoma of the thyroid

Answer

Papillary carcinoma of the thyroid

Answer

Anaplastic carcinoma of the thyroid

Answer

Follicular carcinoma of the thyroid

Question 8

A 28-year-old lady has gained 10 kg over 3 years and presents with oligomenorrhea followed by amenorrhea for 8 months. Her blood pressure is 160/100 mm Hg. Which of the following is the most appropriate investigation?

Accepted Answer

Plasma cortisol

Answer

Serum electrolytes

Answer

Plasma testosterone and ultrasound evaluation of pelvis

Answer

T3, T4 and TSH

Question 9

Which of the following statements about Cushing's syndrome is true?

Accepted Answer

ACTH secretion is the commonest cause.

Answer

Low-dose dexamethasone suppresses cortisol secretion.

Answer

Carcinoma of the adrenal gland is more common than adenoma.

Answer

Pituitary adenoma size is usually greater than 2 cm.

Question 10

Which of the following statements regarding SIADH is FALSE?

Accepted Answer

Vaptans are new FDA-approved drugs for its treatment.

Answer

Serum sodium can be less than 135 mEq/L.

Answer

Urine sodium is normal or slightly low.

Answer

Water loading test can be used.

Endocrinology — MCQs

Endocrinology — MCQs

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