Endocrinology Practice Questions

Q: The secretin stimulation test is used for the diagnosis of which of the following conditions?

Gastrinoma. The **Secretin Stimulation Test** is the most sensitive and specific provocative test for diagnosing **Gastrinoma (Zollinger-Ellison Syndrome)**, particularly when fasting gastrin levels are suggestive but not diagnostic (between 200–1000 pg/mL). **1. Why Gastrinoma is correct:** Under normal physiological conditions, secretin inhibits gastric acid secretion and gastrin release from G-cells. However, **gastrinoma cells** (neuroendocrine tumor cells) possess secretin receptors that, when stimulated, paradoxically cause a massive release of gastrin. A positive test is defined as a rise in serum gastrin levels of **>200 pg/mL** above the baseline following an intravenous bolus of secretin. **2. Why other options are incorrect:** * **Pituitary Adenoma:** Diagnosed via hormonal assays (e.g., Prolactin, GH) and MRI brain. Secretin has no physiological role in the pituitary axis. * **Incidentaloma:** This is an asymptomatic adrenal mass found accidentally on imaging. Diagnosis involves ruling out malignancy and hormonal hypersecretion (e.g., dexamethasone suppression test for Cushing’s). * **Insulinoma:** Diagnosed using the **72-hour fasting test**, which demonstrates the "Whipple’s Triad" (hypoglycemic symptoms, low plasma glucose, and relief of symptoms after glucose administration). **Clinical Pearls for NEET-PG:** * **ZES Location:** Most gastrinomas are found in the **"Gastrinoma Triangle"** (bounded by the confluence of the cystic/common bile duct, the junction of the 2nd and 3rd portions of the duodenum, and the neck/body of the pancreas). * **MEN-1 Association:** Approximately 25% of gastrinomas are associated with Multiple Endocrine Neoplasia Type 1 (3Ps: Pituitary, Parathyroid, Pancreas). * **Initial Screening:** The first step in diagnosis is measuring **Fasting Serum Gastrin (FSG)** levels while the patient is off Proton Pump Inhibitors (PPIs).

Q: A 60-year-old woman presents with symptoms of weight loss, anxiety, and palpitations. On examination, she has a thyroid goiter. Which of the following is the most likely cardiac finding?

Paroxysmal atrial fibrillation. The clinical presentation of weight loss, anxiety, palpitations, and a goiter in an elderly patient is highly suggestive of **Hyperthyroidism** (likely Toxic Multinodular Goiter or Graves' disease). **1. Why Paroxysmal Atrial Fibrillation is Correct:** Thyroid hormones have a direct stimulatory effect on the myocardium and increase the expression of beta-adrenergic receptors. This leads to increased heart rate, contractility, and cardiac irritability. **Atrial Fibrillation (AF)** is the most common rhythm disturbance in hyperthyroidism, occurring in 10–15% of patients, particularly in those over age 60 [1]. It often starts as paroxysmal episodes before becoming persistent. In older patients, tachycardia or atrial fibrillation are prominent signs [3]. **2. Why the Other Options are Incorrect:** * **Prolonged circulation time:** In hyperthyroidism, the circulation time is actually **shortened** due to increased cardiac output and rapid blood flow. Prolonged circulation time is a feature of hypothyroidism or congestive heart failure. * **Decreased cardiac output:** Hyperthyroidism causes a **high-output state**. Thyroid hormones decrease systemic vascular resistance and increase stroke volume and heart rate, leading to elevated cardiac output. * **Pericardial effusion:** This is a classic finding in **Hypothyroidism** (Myxedema), caused by increased capillary permeability and decreased lymphatic drainage. **Clinical Pearls for NEET-PG:** * **Apathetic Hyperthyroidism:** In elderly patients, typical signs like tremors or goiter may be absent; they may present only with unexplained AF or heart failure [3]. * **Treatment:** The first-line management for symptomatic tachycardia/AF in hyperthyroidism is **Beta-blockers** (e.g., Propranolol) to control adrenergic symptoms [2]. * **Reversibility:** AF in hyperthyroidism often reverts to sinus rhythm once a euthyroid state is achieved, especially in younger patients.

Q: Hyponatremia is seen in which of the following conditions?

Hypothyroidism. **Explanation:** **Hypothyroidism** is a well-recognized cause of euvolemic hyponatremia [1]. The underlying pathophysiology involves two primary mechanisms: 1. **Increased ADH Secretion:** Severe hypothyroidism leads to a decrease in cardiac output and systemic vascular resistance. This triggers the "non-osmotic" release of Antidiuretic Hormone (ADH) via carotid baroreceptors, leading to water retention and dilutional hyponatremia [1]. 2. **Reduced Free Water Clearance:** Thyroid hormones are essential for achieving maximum urinary dilution. Their deficiency reduces the glomerular filtration rate (GFR) and impairs the delivery of filtrate to the distal nephron, limiting the kidney's ability to excrete free water [1]. **Analysis of Incorrect Options:** * **Hyperthyroidism:** Generally does not cause hyponatremia; it is more commonly associated with hypercalcemia due to increased bone turnover. * **Diabetes Mellitus:** While uncontrolled DM can cause "pseudohyponatremia" (hyperglycemia shifts water from ICF to ECF), the primary electrolyte concern is osmotic diuresis leading to dehydration. * **Increased Insensible Water Loss:** (e.g., fever, sweating) results in the loss of hypotonic fluid, which typically leads to **hypernatremia** due to a relative deficit of free water. **High-Yield Clinical Pearls for NEET-PG:** * Hyponatremia in hypothyroidism is usually seen in severe cases or **Myxedema Coma**. [1] * It is classified as **Euvolemic Hyponatremia** (similar to SIADH) [1]. * **Rule of thumb:** If a patient has hyponatremia and elevated TSH, thyroid hormone replacement (Levothyroxine) will usually correct the sodium levels without requiring fluid restriction.

Q: Which of the following is NOT a disadvantage of radioactive iodine therapy?

High chances of relapse. Radioactive Iodine (RAI), specifically **I-131**, is a definitive treatment for hyperthyroidism (Graves' disease and Toxic Multinodular Goiter). [1] ### **Explanation of the Correct Answer** **Option B (High chances of relapse)** is the correct answer because it is **not** a disadvantage. In fact, RAI is highly effective with a success rate exceeding 80-90% after a single dose. Unlike Antithyroid Drugs (ATDs), which have a relapse rate of approximately 50-60% after discontinuation, RAI provides a permanent solution by destroying the overactive thyroid follicular cells. ### **Analysis of Incorrect Options** * **A. Hypothyroidism:** This is the most common long-term complication of RAI. Since the goal is to ablate the gland, most patients eventually become hypothyroid (up to 80% in the first year) and require lifelong Levothyroxine. * **C. Delayed therapeutic effect:** RAI does not work instantly. It takes **2–3 months** to achieve a euthyroid state. Patients often require "pretreatment" with beta-blockers or ATDs to control symptoms during this lag period. * **D. Development of thyroid carcinoma:** While large-scale studies show no significant increase in thyroid cancer risk in adults, the *theoretical* risk of secondary malignancy and the potential for genetic damage in young patients remain classic "textbook" concerns and contraindications for children and pregnant women. [1] ### **NEET-PG Clinical Pearls** * **Absolute Contraindications:** Pregnancy (causes fetal thyroid ablation) and Breastfeeding. [1] * **Relative Contraindication:** Severe Graves' Ophthalmopathy (RAI can worsen proptosis; prophylactic steroids are given if RAI is used). [1] * **Mechanism:** I-131 emits **Beta-particles** (responsible for tissue destruction) and Gamma-rays (used for imaging). * **Pre-procedure:** Stop Methimazole 3–5 days before RAI to ensure maximum iodine uptake.

Q: In prolactinoma, what is the most common symptom other than galactorrhea?

Amenorrhea. **Explanation:** The most common symptom of a prolactinoma in females, other than galactorrhea, is **Amenorrhea** (specifically secondary amenorrhea). **Pathophysiology:** High levels of prolactin exert a negative feedback effect on the hypothalamus, inhibiting the pulsatile release of **Gonadotropin-Releasing Hormone (GnRH)**. This leads to decreased secretion of LH and FSH from the anterior pituitary, resulting in hypogonadotropic hypogonadism. In women, this manifests as oligomenorrhea or amenorrhea and infertility; in men, it presents as decreased libido and erectile dysfunction. **Analysis of Incorrect Options:** * **A. Bitemporal hemianopia:** This occurs due to the compression of the optic chiasm by a **macroadenoma** (>10mm). While classic, it is less common than endocrine symptoms because most prolactinomas in women are microadenomas detected early due to menstrual irregularities. * **C. Thyroid dysfunction:** While pituitary tumors can sometimes be part of MEN1 syndrome or cause secondary hypothyroidism via mass effect (TSH deficiency), it is not a primary or common symptom of prolactinoma itself. * **D. Headache:** This is a non-specific symptom caused by increased intracranial pressure or dural stretching by a large tumor. It is less frequent than hormonal disturbances. **Clinical Pearls for NEET-PG:** * **Most common functioning pituitary adenoma:** Prolactinoma. * **Drug of choice:** Dopamine agonists (e.g., **Cabergoline** is preferred over Bromocriptine due to higher efficacy and fewer side effects). * **Surgery:** Indicated only if the tumor is refractory to medical therapy or causing acute visual field defects (Transsphenoidal approach). * **Hook Effect:** A laboratory artifact where extremely high prolactin levels (>100,000 ng/mL) saturate the assay, leading to a falsely low reading. Dilution is required for accurate measurement.

Q: All of the following can cause hypersecretion of prolactin, except?

Cabergoline. **Explanation:** The correct answer is **Cabergoline** because it is a **Dopamine (D2) receptor agonist**. In the body, dopamine acts as the primary "Prolactin Inhibiting Factor" (PIF). By stimulating D2 receptors on the lactotrophs of the anterior pituitary, Cabergoline suppresses the synthesis and release of prolactin. Therefore, it is used to *treat* hyperprolactinemia, not cause it. **Analysis of Incorrect Options:** * **Prolactinoma (A):** This is a benign tumor of the pituitary gland (lactotroph adenoma) that autonomously secretes high levels of prolactin. It is the most common pathological cause of hyperprolactinemia. * **Haloperidol (B):** This is a typical antipsychotic that acts as a **D2 receptor antagonist**. By blocking the inhibitory effect of dopamine on the pituitary, it leads to "disinhibition" and subsequent hyperprolactinemia. * **Hypothyroidism (C):** In primary hypothyroidism, low levels of thyroid hormones lead to a compensatory increase in **Thyrotropin-Releasing Hormone (TRH)**. TRH acts as a potent prolactin-releasing factor, thereby increasing prolactin levels. **NEET-PG High-Yield Pearls:** * **Drug of Choice:** Cabergoline is the preferred drug for prolactinomas due to its higher efficacy and better side-effect profile (longer half-life) compared to Bromocriptine. * **Physiological causes:** Pregnancy, lactation, and stress are common non-pathological causes of elevated prolactin. * **Clinical Presentation:** In females, it presents as the **Amenorrhea-Galactorrhea syndrome**; in males, it causes decreased libido, erectile dysfunction, and gynecomastia. * **Stalk Effect:** Any pituitary mass that compresses the pituitary stalk prevents dopamine from reaching the gland, leading to moderately elevated prolactin levels.

Q: A 40-year-old man presents with nausea, vomiting, diarrhea, and cramping abdominal pain. His temperature is 38°C, blood pressure is 90/60 mm Hg, and pulse rate is 90/minute. Physical examination reveals dehydration with sunken eyeballs, dry tongue, and poor skin turgor. Hyperpigmentation is noted in the palmar creases and the gingival margins. Laboratory results include fasting serum glucose of 62 mg/dL, BUN of 27 mg/dL, Na of 122 mEq/L, and K of 6.5 mEq/L. What is the most likely cause of this patient's symptoms?

Autoimmunity. **Explanation:** The clinical presentation of hypotension, dehydration, hypoglycemia, hyponatremia, and hyperkalemia, combined with hyperpigmentation, is classic for **Primary Adrenal Insufficiency (Addison’s Disease)** [2]. The patient is currently in an **Addisonian Crisis**, likely precipitated by an acute stressor [1]. 1. **Why Autoimmunity is Correct:** In developed countries and increasingly in urban India, **Autoimmune Adrenalitis** (either isolated or as part of Polyglandular Autoimmune Syndromes) is the **most common cause** of primary adrenal insufficiency (responsible for ~80% of cases) [3]. It involves the destruction of the adrenal cortex, leading to a deficiency of cortisol (causing hypoglycemia and hypotension) and aldosterone (causing hyponatremia and hyperkalemia). The hyperpigmentation occurs because low cortisol triggers a compensatory increase in ACTH; the precursor molecule (POMC) also produces Melanocyte-Stimulating Hormone (MSH). 2. **Why Incorrect Options are Wrong:** * **Amyloidosis and Sarcoidosis:** These are infiltrative diseases that can involve the adrenal glands, but they are rare causes of clinical adrenal insufficiency compared to autoimmunity. * **Metastatic Cancer:** While cancers (especially lung and breast) frequently metastasize to the adrenals, they rarely destroy >90% of the gland required to cause symptomatic insufficiency [3]. **NEET-PG High-Yield Pearls:** * **Most common cause worldwide:** Autoimmunity (formerly Tuberculosis). * **Most common cause in developing countries/India:** Tuberculosis (look for adrenal calcification on CT) [3]. * **Electrolyte Hallmark:** Hyponatremia + Hyperkalemia + Metabolic Acidosis (Non-gap). * **Diagnosis:** Best initial test is the **ACTH Stimulation Test** (Cosyntropin test) [1]. * **Management of Crisis:** Immediate IV fluids (Normal Saline) and high-dose **IV Hydrocortisone**. Do not wait for lab confirmation [1].

Q: A 59-year-old man with type 2 diabetes presents for a screening eye examination. The ophthalmologist reports the development of non-proliferative retinopathy. For this patient with a complication of diabetes, select the most likely findings.

Microaneurysms and hemorrhage (dot and blot). **Explanation:** Diabetic Retinopathy (DR) is a leading cause of blindness and is categorized into Non-Proliferative (NPDR) and Proliferative (PDR) stages. **Why Option A is Correct:** The earliest clinical sign of NPDR is the formation of **microaneurysms**, which appear as small red dots due to capillary wall outpouching [1]. As these capillaries leak or rupture within the deeper layers of the retina (inner nuclear and outer plexiform layers), they create **"dot and blot" hemorrhages**. Other features of NPDR include hard exudates (lipid leaks) and cotton wool spots (nerve fiber layer infarcts). **Analysis of Incorrect Options:** * **B. Vitreous hemorrhage:** This is a hallmark of **Proliferative Diabetic Retinopathy (PDR)** [1]. It occurs when fragile new vessels (neovascularization) bleed into the vitreous cavity [1]. * **C. Dilated veins:** While venous "beading" or loops can occur in severe NPDR, simple dilated veins are more characteristic of Central Retinal Vein Occlusion (CRVO) or early hypertensive changes rather than the primary screening finding for NPDR. * **D. Open-angle glaucoma:** While diabetics have a higher risk of glaucoma, it is a separate pathological entity and not a diagnostic feature of non-proliferative retinopathy. **High-Yield NEET-PG Pearls:** * **Earliest Sign:** Microaneurysms (seen on Fundus Fluorescein Angiography) [1]. * **NPDR vs. PDR:** The defining feature of PDR is **Neovascularization** (NVD/NVE) driven by VEGF [1]. * **Macular Edema:** Can occur at *any* stage of DR and is the most common cause of vision loss in NPDR [1]. * **Screening:** Type 2 DM patients need a fundus exam **at the time of diagnosis**, whereas Type 1 DM patients should be screened **5 years after diagnosis**.

Question 1

Adrenal aldosteronoma is best diagnosed by which of the following?

Accepted Answer

HRCT

Answer

MRI

Answer

JVP

Answer

KUB

Question 2

The secretin stimulation test is used for the diagnosis of which of the following conditions?

Accepted Answer

Gastrinoma

Answer

Pituitary adenoma

Answer

Incidentaloma

Answer

Insulinoma

Question 3

A 60-year-old woman presents with symptoms of weight loss, anxiety, and palpitations. On examination, she has a thyroid goiter. Which of the following is the most likely cardiac finding?

Accepted Answer

Paroxysmal atrial fibrillation

Answer

Prolonged circulation time

Answer

Decreased cardiac output

Answer

Pericardial effusion

Question 4

Hyponatremia is seen in which of the following conditions?

Accepted Answer

Hypothyroidism

Answer

Hyperthyroidism

Answer

Diabetes Mellitus

Answer

Increased insensible water loss

Question 5

Which of the following is NOT a disadvantage of radioactive iodine therapy?

Accepted Answer

High chances of relapse

Answer

Hypothyroidism

Answer

Delayed therapeutic effect

Answer

Development of thyroid carcinoma

Question 6

In prolactinoma, what is the most common symptom other than galactorrhea?

Accepted Answer

Amenorrhea

Answer

Bitemporal hemianopia

Answer

Thyroid dysfunction

Answer

Headache

Question 7

All of the following can cause hypersecretion of prolactin, except?

Accepted Answer

Cabergoline

Answer

Prolactinoma

Answer

Haloperidol

Answer

Hypothyroidism

Question 8

Which of the following statements regarding obesity syndromes are true or false?

Accepted Answer

Prader-Willi syndrome has normal stature with truncal obesity; Laurence-Moon-Biedl is autosomal with polydactyly; Ahlstrom's syndrome patients have moderate mental retardation; Cohen's syndrome patients have craniofacial anomalies and delayed puberty; Carpenter's syndrome have secondary hypogonadism are all true, except Prader-Willi syndrome and Ahlstrom's syndrome are false.

Answer

Prader-Willi syndrome has normal stature with truncal obesity; Laurence-Moon-Biedl is autosomal with polydactyly; Ahlstrom's syndrome patients have moderate mental retardation; Cohen's syndrome patients have craniofacial anomalies and delayed puberty; Carpenter's syndrome have secondary hypogonadism are all true, except Laurence-Moon-Biedl is false.

Answer

Prader-Willi syndrome has normal stature with truncal obesity; Laurence-Moon-Biedl is autosomal with polydactyly; Ahlstrom's syndrome patients have moderate mental retardation; Cohen's syndrome patients have craniofacial anomalies and delayed puberty; Carpenter's syndrome have secondary hypogonadism are all true, except Prader-Willi syndrome is false.

Answer

Prader-Willi syndrome has normal stature with truncal obesity; Laurence-Moon-Biedl is autosomal with polydactyly; Ahlstrom's syndrome patients have moderate mental retardation; Cohen's syndrome patients have craniofacial anomalies and delayed puberty; Carpenter's syndrome have secondary hypogonadism are all true, except Prader-Willi syndrome and Carpenter's syndrome are false.

Question 9

A 40-year-old man presents with nausea, vomiting, diarrhea, and cramping abdominal pain. His temperature is 38°C, blood pressure is 90/60 mm Hg, and pulse rate is 90/minute. Physical examination reveals dehydration with sunken eyeballs, dry tongue, and poor skin turgor. Hyperpigmentation is noted in the palmar creases and the gingival margins. Laboratory results include fasting serum glucose of 62 mg/dL, BUN of 27 mg/dL, Na of 122 mEq/L, and K of 6.5 mEq/L. What is the most likely cause of this patient's symptoms?

Accepted Answer

Autoimmunity

Answer

Amyloidosis

Answer

Metastatic cancer

Answer

Sarcoidosis

Question 10

A 59-year-old man with type 2 diabetes presents for a screening eye examination. The ophthalmologist reports the development of non-proliferative retinopathy. For this patient with a complication of diabetes, select the most likely findings.

Accepted Answer

Microaneurysms and hemorrhage (dot and blot)

Answer

Vitreous hemorrhage

Answer

Dilated veins

Answer

Open-angle glaucoma

Endocrinology — MCQs

Endocrinology — MCQs

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