Endocrinology Practice Questions

Q: What does the HbA1c level in blood explain?

Long-term status of blood sugar. Explanation: **HbA1c (Glycated Hemoglobin)** is the gold standard for monitoring glycemic control in patients with Diabetes Mellitus. It represents the percentage of hemoglobin that has glucose chemically linked to it through a non-enzymatic process called **glycation** [3]. 1. **Why Option B is Correct:** The binding of glucose to hemoglobin is irreversible and depends directly on the ambient glucose concentration [1]. Since the average lifespan of a Red Blood Cell (RBC) is approximately **120 days**, the HbA1c level reflects the average blood glucose levels over the preceding **2–3 months** [2]. This makes it an ideal marker for assessing the **long-term status of blood sugar** rather than daily fluctuations [1], [2]. 2. **Why Other Options are Incorrect:** * **Option A:** Acute rises in blood sugar (post-prandial spikes or stress hyperglycemia) are measured using Fasting Blood Sugar (FBS) or Post-Prandial Blood Sugar (PPBS). HbA1c remains stable despite acute daily changes. * **Option C & D:** Hepatorenal syndrome (renal failure in the setting of liver cirrhosis) and Chronic pancreatitis (inflammation of the pancreas) are distinct clinical entities. While chronic pancreatitis can lead to secondary diabetes (Type 3c), HbA1c is a marker of the resulting glucose levels, not the disease process itself. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnostic Threshold:** An HbA1c **≥ 6.5%** is diagnostic for Diabetes Mellitus. * **False Lows:** Conditions that decrease RBC lifespan (e.g., Hemolytic anemia, acute blood loss, Pregnancy, Erythropoietin therapy) will falsely lower HbA1c. * **False Highs:** Conditions that increase RBC lifespan (e.g., Iron deficiency anemia, Vitamin B12 deficiency) or Splenectomy can falsely elevate HbA1c. * **Formula:** Estimated Average Glucose (eAG) = $28.7 \times \text{HbA1c} - 46.7$.

Q: Which drug is given for painful tingling of diabetic neuropathy?

All of them. **Explanation:** Diabetic Peripheral Neuropathy (DPN) often presents with "positive" symptoms like painful tingling, burning sensations, and electric-shock-like pain [1]. The management of painful DPN involves drugs that modulate neurotransmission to increase the pain threshold. **Why "All of them" is correct:** Current clinical guidelines (ADA and AAN) recommend several classes of drugs as first-line agents for painful diabetic neuropathy. * **Gabapentin and Pregabalin (Option A & C):** These are **Calcium Channel Alpha-2-Delta ($\alpha_2\delta$) ligands**. They bind to the voltage-gated calcium channels in the CNS, reducing the release of excitatory neurotransmitters (like glutamate and substance P), thereby dampening pain signals [2]. * **Duloxetine (Option B):** This is a **Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)**. It enhances the descending inhibitory pain pathways in the spinal cord by increasing the synaptic concentration of serotonin and norepinephrine. Since all three drugs are FDA-approved and clinically effective first-line treatments for this condition, "All of them" is the correct choice. **High-Yield Clinical Pearls for NEET-PG:** * **First-line agents:** Pregabalin, Gabapentin, Duloxetine, and Tricyclic Antidepressants (TCAs like Amitriptyline). * **Pregabalin vs. Gabapentin:** Pregabalin has more predictable pharmacokinetics and quicker onset of action. * **Side Effects:** * Gabapentinoids: Sedation, dizziness, and peripheral edema. * Duloxetine: Nausea (most common), dry mouth, and insomnia. * **Avoid:** Opioids are generally not recommended as first-line therapy due to the risk of addiction and lack of long-term efficacy [2]. * **Aldose Reductase Inhibitors:** (e.g., Epalrestat) target the polyol pathway but are less commonly used than the above symptomatic treatments.

Q: A 20-year-old male presents with chronic constipation, headache, Marfanoid habitus, neuromas of the tongue, medullated corneal nerve fibers, and a 2x2 cm nodule in the left lobe of the thyroid. What is the most probable diagnosis?

Multiple Endocrine Neoplasia (MEN) 2B. ### Explanation The correct diagnosis is **Multiple Endocrine Neoplasia (MEN) 2B**. [1] **1. Why MEN 2B is correct:** MEN 2B (formerly MEN 3) is characterized by a triad of **Medullary Thyroid Carcinoma (MTC)**, **Pheochromocytoma**, and distinctive **mucocutaneous manifestations**. [1] This patient exhibits the classic "phenotype" of MEN 2B: * **Marfanoid Habitus:** Long limbs and lax joints (without the lens dislocation or aortic issues seen in true Marfan syndrome). * **Mucosal Neuromas:** Fleshy bumps on the tongue, lips, and eyelids. * **Intestinal Ganglioneuromatosis:** This leads to chronic constipation or megacolon. * **Medullated Corneal Nerve Fibers:** A high-yield ophthalmological finding specific to this syndrome. * **Thyroid Nodule:** In MEN 2B, MTC occurs early (often in childhood) and is highly aggressive. [1] **2. Why other options are incorrect:** * **MEN 2A:** While it also features MTC and Pheochromocytoma, it is associated with **Primary Hyperparathyroidism** and *Lichen Amyloidosis*, not Marfanoid habitus or mucosal neuromas. * **Sporadic/Familial MTC:** These involve MTC without the associated syndromic features like neuromas, Marfanoid habitus, or other endocrine tumors (like pheochromocytoma). **3. NEET-PG High-Yield Pearls:** * **Genetics:** All MEN 2 syndromes are caused by a germline mutation in the **RET proto-oncogene** (Chromosome 10). [1] * **Management:** Due to the extreme aggressiveness of MTC in MEN 2B, prophylactic thyroidectomy is recommended **within the first year of life**. [1] * **Screening:** Always rule out **Pheochromocytoma** (via urinary/plasma metanephrines) before performing thyroid surgery to prevent a hypertensive crisis during anesthesia. [2]

Q: Migratory necrolytic erythema is seen in which condition?

Glucagonoma syndrome. **Explanation:** **Migratory Necrolytic Erythema (MNE)** is the pathognomonic cutaneous manifestation of **Glucagonoma syndrome**, a rare neuroendocrine tumor of the pancreatic alpha cells [1]. 1. **Why Glucagonoma is correct:** MNE presents as pruritic, painful, erythematous plaques that blister and crust, typically involving the perineum, extremities, and perioral areas. The underlying mechanism involves hyperglucagonemia leading to increased gluconeogenesis and protein catabolism, resulting in hypoaminoacidemia. This nutritional deficiency, along with zinc and essential fatty acid depletion, is thought to trigger epidermal necrosis. 2. **Why other options are incorrect:** * **Peutz-Jeghers Syndrome:** Characterized by hamartomatous GI polyps and **mucocutaneous hyperpigmentation** (melanotic macules) on the lips and buccal mucosa. * **Sarcoidosis:** Classically associated with **Lupus Pernio** (violaceous plaques on the nose/cheeks) and Erythema Nodosum. * **Amyloidosis:** Skin findings typically include **waxy papules**, plaques, and "pinch purpura" (ecchymosis following minor trauma), especially in the periorbital area. **High-Yield Clinical Pearls for NEET-PG:** * **The "6Ds" of Glucagonoma:** **D**ermatitis (MNE), **D**iabetes (mild), **D**epression, **D**eclining weight, **D**eep vein thrombosis (DVT), and **D**iarrhea [1]. * **Diagnosis:** Markedly elevated fasting plasma glucagon levels (>1000 pg/mL). * **Treatment:** Surgical resection is definitive; Octreotide (somatostatin analog) is used to manage symptoms by inhibiting glucagon release.

Q: Conn's syndrome is characterized by diastolic hypertension without edema. Which of the following is a characteristic electrolyte imbalance seen in Conn's syndrome?

Hypokalemia. **Explanation:** **Conn’s Syndrome** (Primary Hyperaldosteronism) is caused by an aldosterone-secreting adenoma of the adrenal cortex. The pathophysiology revolves against the excessive action of aldosterone on the **principal cells** of the renal collecting ducts. 1. **Why Hypokalemia is correct:** Aldosterone increases the activity of the ENaC (epithelial sodium channels), leading to sodium reabsorption. To maintain electrochemical neutrality, the kidney must excrete positive ions, specifically **Potassium (K+)** and Hydrogen (H+) [1]. This results in excessive urinary potassium loss, leading to **hypokalemia** and metabolic alkalosis [3]. 2. **Analysis of Incorrect Options:** * **B. Hyperkalemia:** This is the opposite of the expected finding. Hyperkalemia is seen in Addison’s disease (adrenal insufficiency) or Hypoaldosteronism. * **C. Sodium retention:** While sodium is indeed retained, it is **not** an electrolyte imbalance typically measured as "hypernatremia." Due to the **"Aldosterone Escape"** phenomenon (where increased ANP and pressure natriuresis prevent fluid overload), sodium levels usually remain at the high end of the normal range, and clinical edema is absent [2]. * **D. Hypertension:** While hypertension is a hallmark clinical feature of Conn’s syndrome, the question specifically asks for a characteristic **electrolyte imbalance**. **High-Yield Clinical Pearls for NEET-PG:** * **Screening Test:** Plasma Aldosterone Concentration (PAC) to Plasma Renin Activity (PRA) ratio. A ratio **>20-30** is suggestive. * **Confirmatory Test:** Saline infusion test or Oral salt loading test (failure to suppress aldosterone). * **Aldosterone Escape:** Explains why patients with Conn’s syndrome do not develop overt volume overload or edema despite sodium retention [2]. * **Triad:** Hypertension + Hypokalemia + Metabolic Alkalosis.

Question 1

What does the HbA1c level in blood explain?

Accepted Answer

Long-term status of blood sugar

Answer

Acute rise of blood sugar

Answer

Hepatorenal syndrome

Answer

Chronic pancreatitis

Question 2

A patient presents with bilateral proptosis, heat intolerance, and palpitations. What is the most likely diagnosis?

Accepted Answer

Diffuse thyroid goitre

Answer

Hashimoto's thyroiditis

Answer

Thyroid adenoma

Answer

Reidel's thyroiditis

Question 3

A 25-year-old man presents with 3 months of polyuria and increased thirst. The patient suffered trauma to the base of the skull in a motorcycle accident 4 months ago. A 24-hour urine collection shows polyuria but no evidence of hematuria, glucosuria, or proteinuria. The pathogenesis of polyuria in this patient is most likely caused by a lesion in which of the following areas of the brain?

Accepted Answer

Neurohypophysis

Answer

Adenohypophysis

Answer

Brain stem

Answer

Mammillothalamic tract

Question 4

High T3, high T4, low TSH, and low radioiodine uptake is seen in which condition?

Accepted Answer

Subacute thyroiditis

Answer

Hashimoto's thyroiditis

Answer

Graves' disease

Answer

Toxic nodule

Question 5

Which of the following is NOT a risk factor for severe hypoglycemia?

Accepted Answer

Sleep

Answer

Short duration of diabetes mellitus

Answer

ACE genotype

Answer

Strict control of blood sugar level

Question 6

Which drug is given for painful tingling of diabetic neuropathy?

Accepted Answer

All of them

Answer

Gabapentin

Answer

Duloxetine

Answer

Pregabalin

Question 7

A 65-year-old woman with a history of multinodular goiter complains of increasing nervousness, insomnia, and heart palpitations. She has lost 9 kg over the past 6 months. There is no evidence of exophthalmos. Laboratory studies show elevated serum levels of free T3 and T4. Serologic tests for antithyroid antibodies are negative. Which of the following is the likely endocrinopathy in this patient?

Accepted Answer

Thyrotoxicosis

Answer

Thyroid storm

Answer

Graves disease

Answer

Hypothyroidism

Question 8

A 20-year-old male presents with chronic constipation, headache, Marfanoid habitus, neuromas of the tongue, medullated corneal nerve fibers, and a 2x2 cm nodule in the left lobe of the thyroid. What is the most probable diagnosis?

Accepted Answer

Multiple Endocrine Neoplasia (MEN) 2B

Answer

Sporadic medullary carcinoma of the thyroid

Answer

Familial medullary carcinoma of the thyroid

Answer

Multiple Endocrine Neoplasia (MEN) 2A

Question 9

Migratory necrolytic erythema is seen in which condition?

Accepted Answer

Glucagonoma syndrome

Answer

Peutz-Jeghers syndrome

Answer

Sarcoidosis

Answer

Amyloidosis

Question 10

Conn's syndrome is characterized by diastolic hypertension without edema. Which of the following is a characteristic electrolyte imbalance seen in Conn's syndrome?

Accepted Answer

Hypokalemia

Answer

Hyperkalemia

Answer

Sodium retention

Answer

Hypertension

Endocrinology — MCQs

Endocrinology — MCQs

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