Endocrinology Practice Questions

Q: A 25-year-old female presents with a 12-month history of palpitations, intermittent diarrhea, anxiety, and a 1-month history of "bulging of both eyes." What is the most likely cause of her symptoms?

Graves' disease. **Explanation:** The clinical presentation of palpitations, diarrhea, anxiety, and weight loss (implied by the systemic symptoms) points toward **Hyperthyroidism** [3]. The pathognomonic finding in this case is the **"bulging of both eyes" (Exophthalmos/Graves' Ophthalmopathy)** [2]. **1. Why Graves' Disease is Correct:** Graves' disease is an autoimmune disorder caused by **Thyroid Stimulating Immunoglobulins (TSI)** that bind to and activate the TSH receptor [1]. It is the most common cause of hyperthyroidism in young women [3]. It is characterized by a classic triad: Hyperthyroidism, Diffuse Goiter, and **Ophthalmopathy** [1]. The eye changes occur due to the activation of TSH receptors on orbital fibroblasts, leading to glycosaminoglycan accumulation and extraocular muscle edema—a feature **not** seen in other causes of hyperthyroidism [2]. **2. Why Other Options are Incorrect:** * **Hashimoto’s Thyroiditis:** Typically presents with features of *hypothyroidism* (weight gain, constipation, cold intolerance). While a transient "Hashitoxicosis" can occur, it does not cause ophthalmopathy. * **Multinodular Toxic Goiter (Plummer Disease):** Common in older age groups. While it causes hyperthyroidism, it is characterized by nodules and **lacks** the extrathyroidal manifestations like exophthalmos [2]. * **Papillary Carcinoma:** The most common thyroid malignancy; it usually presents as a painless, euthyroid cold nodule and does not typically cause hyperthyroidism or exophthalmos. **Clinical Pearls for NEET-PG:** * **Graves' Triad:** Hyperthyroidism, Exophthalmos, and Pretibial Myxedema (Dermopathy) [1]. * **Diagnosis:** Low TSH, High T3/T4, and **diffuse increased uptake** on Radioactive Iodine Uptake (RAIU) scan [3]. * **Specific Marker:** TSH Receptor Antibodies (TRAb/TSI) [1]. * **Smoking** is the most significant risk factor for the worsening of Graves' ophthalmopathy.

Q: Hypothyroidism caused by a viral infection of the thyroid gland is a pathologic condition associated with which of the following blood hormone levels?

High TSH. ### Explanation **1. Why the Correct Answer is Right:** Hypothyroidism caused by a viral infection refers to **Subacute Granulomatous Thyroiditis (De Quervain’s Thyroiditis)**. While this condition typically presents with a transient phase of hyperthyroidism (due to the release of preformed hormones), it is frequently followed by a **hypothyroid phase** as the gland's hormone stores are depleted and the follicular cells are recovering [2]. In any form of **primary hypothyroidism** (where the defect is in the thyroid gland itself), the low levels of circulating T3 and T4 remove the negative feedback on the anterior pituitary [1]. This results in a compensatory **increase in Thyroid Stimulating Hormone (TSH)** [1]. Therefore, high TSH is the hallmark biochemical marker of primary hypothyroidism. **2. Why the Incorrect Options are Wrong:** * **High Prolactin (PRL):** While severe primary hypothyroidism can cause hyperprolactinemia (because high TRH acts as a prolactin-releasing factor), it is not the primary diagnostic hormone level associated with viral-induced thyroiditis. * **High Cortisol:** Cortisol levels are typically unaffected by thyroiditis. High cortisol is associated with Cushing’s syndrome or acute stress, not hypothyroidism. * **Low Growth Hormone (GH):** While thyroid hormones are necessary for normal GH secretion in children (leading to growth retardation in cretinism), GH levels are not a standard diagnostic parameter for adult viral thyroiditis. **3. Clinical Pearls for NEET-PG:** * **De Quervain’s Thyroiditis:** Characterized by a **painful/tender thyroid gland**, often following an upper respiratory tract infection. * **ESR:** Typically very high (>50-100 mm/hr) [2]. * **Radioactive Iodine Uptake (RAIU):** Characteristically **low** during the thyrotoxic phase (due to follicular cell damage) [2]. * **Treatment:** NSAIDs for mild cases; Steroids for severe pain [2]. It is usually self-limiting.

Q: Which type of diabetes is characterized by impaired glucose-induced insulin secretion with preserved beta-cell mass?

Maturity-onset diabetes of the young (MODY). **Explanation:** The correct answer is **Maturity-onset diabetes of the young (MODY)**. **Why MODY is correct:** MODY is a group of monogenic disorders characterized by **functional defects** in beta-cell glucose sensing or insulin secretion, rather than the destruction of the cells themselves [2]. In MODY (especially MODY 2 and MODY 3), the **beta-cell mass remains preserved**, but there is a "blindness" to glucose or a defect in the stimulus-secretion coupling. For example, in MODY 2 (Glucokinase mutation), the "glucose sensor" has a higher threshold, requiring higher glucose levels to trigger insulin release. **Why other options are incorrect:** * **Type 1 Diabetes:** Characterized by autoimmune-mediated **destruction of beta-cells**, leading to an absolute deficiency of insulin and a significant loss of beta-cell mass [1]. * **LADA (Latent Autoimmune Diabetes in Adults):** Often called "Type 1.5," it involves a slow-progressing autoimmune attack. Like Type 1, it eventually leads to a **reduction in beta-cell mass**. * **Wolfram Syndrome (DIDMOAD):** A rare genetic neurodegenerative disorder (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy, and Deafness). The DM here is caused by progressive **beta-cell loss** due to endoplasmic reticulum stress (WFS1 gene mutation). **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** MODY follows an **Autosomal Dominant** pattern (look for 3 generations of early-onset DM in the history) [2]. * **Most Common Type:** **MODY 3** (HNF-1α mutation) is the most common globally; **MODY 2** (Glucokinase) is the second most common. * **Treatment:** Patients with MODY 3 are exquisitely sensitive to **Low-dose Sulfonylureas**, which bypass the glucose-sensing defect. * **Key Differentiator:** Unlike Type 1 DM, MODY is **Ketosis-negative** and **Autoantibody-negative** (GAD/ICA negative).

Q: Osteitis fibrosa cystica refers to:

Hyperparathyroidism.. **Explanation:** **Osteitis fibrosa cystica (OFC)**, also known as von Recklinghausen's disease of bone, is the classic skeletal manifestation of advanced **Hyperparathyroidism** (most commonly primary) [1]. **Why Hyperparathyroidism is correct:** In hyperparathyroidism, excess Parathyroid Hormone (PTH) overstimulates osteoclasts, leading to rapid bone resorption [2]. The bone is replaced by vascular fibrous tissue. As the process progresses, it results in thinning of the cortex, marrow fibrosis, and the formation of cystic lesions known as **"Brown tumors."** These are not true neoplasms but are collections of giant cells and hemorrhagic debris (hemosiderin) that appear brown macroscopically. **Why other options are incorrect:** * **Paget’s Disease:** Characterized by disordered bone remodeling (excessive resorption followed by disorganized formation), leading to a "mosaic pattern" and thickened but weak bones. * **Fibrous Dysplasia:** A genetic condition where normal bone is replaced by fibrous tissue and immature "woven" bone (Chinese-letter pattern), but it is not driven by PTH. * **Osteogenesis Imperfecta:** A genetic disorder of Type I collagen synthesis leading to brittle bones and blue sclera, unrelated to parathyroid activity. **High-Yield Clinical Pearls for NEET-PG:** * **Radiological Hallmark:** Subperiosteal bone resorption, most characteristically seen on the **radial aspect of the middle phalanges**. * **Skull Appearance:** "Salt and pepper" appearance due to patchy demineralization. * **Biochemical Profile:** Elevated Serum Calcium, Low Serum Phosphate, and Elevated PTH [1]. * **Brown Tumors:** These typically regress once the underlying hyperparathyroidism is surgically treated.

Q: Which of the following is not a characteristic feature of Multiple Endocrine Neoplasia type 1 (MEN1)?

Posterior pituitary tumors. **Explanation:** Multiple Endocrine Neoplasia type 1 (MEN1), 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"**: Parathyroid, Pancreas, and Pituitary. **Why Option A is correct:** While pituitary adenomas are a hallmark of MEN1, they almost exclusively involve the **Anterior Pituitary** (adenohypophysis). Prolactinomas are the most common, followed by somatotropinomas (GH-secreting). The **Posterior Pituitary** (neurohypophysis) is not involved in the MEN1 syndrome, making this the "except" or incorrect feature. **Why other options are incorrect:** * **B. Foregut Carcinoids:** These are recognized components of MEN1. They include thymic, bronchial, and gastric carcinoids. Thymic carcinoids are particularly aggressive and are a significant cause of mortality in these patients. * **C. Parathyroid Hyperplasia:** This is the **most common** (95% of patients) and usually the earliest clinical manifestation of MEN1. It typically involves multiglandular hyperplasia rather than a single adenoma. * **D. Pancreatic Neuroendocrine Tumors (pNETs):** These occur in about 60-70% of patients. Gastrinomas (leading to Zollinger-Ellison Syndrome) are the most common symptomatic pNET, followed by Insulinomas. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Autosomal Dominant; Chromosome **11q13**. * **Most common feature:** Primary Hyperparathyroidism. * **Most common pituitary tumor:** Prolactinoma. * **Cutaneous markers:** Angiofibromas, collagenomas, and lipomas are frequently seen and can aid in early clinical diagnosis. * **Screening:** Annual biochemical screening (Calcium, PTH, Gastrin, Prolactin) is recommended for carriers starting in childhood.

Q: Which statement is not true regarding hypocalcemia?

Inverse relation with magnesium levels. ### Explanation **1. Why Option D is the Correct Answer (The False Statement)** The relationship between magnesium and calcium is **direct**, not inverse. Magnesium is essential for the synthesis and release of Parathyroid Hormone (PTH) and for the responsiveness of target organs to PTH [1]. * **Hypomagnesemia** leads to functional hypoparathyroidism, causing **hypocalcemia** [1]. * Severe magnesium deficiency inhibits PTH secretion and induces PTH resistance. Therefore, to correct hypocalcemia in such patients, magnesium must be replenished first [1]. **2. Analysis of Incorrect Options (True Statements)** * **Option A (Hypoparathyroidism):** This is the most common cause of hypocalcemia. PTH is the primary hormone responsible for increasing serum calcium; its deficiency leads to decreased bone resorption and renal calcium reabsorption [1], [2]. * **Option B (Latent Tetany):** Hypocalcemia increases neuromuscular excitability. Latent tetany refers to neuromuscular irritability that is not clinically apparent but can be elicited by provocative tests like **Chvostek’s sign** (facial twitching) and **Trousseau’s sign** (carpal spasm). * **Option C (Prolonged QT Interval):** On ECG, hypocalcemia characteristically causes prolongation of the ST segment, which leads to a **prolonged QT interval** [1]. This is a high-yield diagnostic marker. **3. Clinical Pearls for NEET-PG** * **Trousseau’s Sign** is more specific for hypocalcemia than Chvostek’s sign. * **Hungry Bone Syndrome:** Severe hypocalcemia seen post-parathyroidectomy or thyroidectomy. * **Correction Formula:** For every 1 g/dL drop in serum albumin below 4 g/dL, add 0.8 mg/dL to the measured calcium level to get the **Corrected Calcium** [1]. * **Hyperphosphatemia** is typically seen in hypoparathyroidism, whereas **hypophosphatemia** is seen in Vitamin D deficiency [1].

Q: Which is the most common clinical feature of pheochromocytoma?

Headaches. Explanation: Pheochromocytoma is a catecholamine-secreting tumor arising from the chromaffin cells of the adrenal medulla. The clinical presentation is characterized by the classic triad of **Headache, Sweating (Diaphoresis), and Palpitations**, occurring in the setting of hypertension. **Why Headaches are the correct answer:** Among the classic symptoms, **headache** is the most common clinical feature, occurring in approximately 60–90% of symptomatic patients. These headaches are typically paroxysmal, severe, and bilateral. They are caused by the sudden, massive release of catecholamines leading to severe surges in blood pressure (hypertensive crisis). **Analysis of Incorrect Options:** * **A. Profuse sweating:** While a key component of the classic triad (occurring in ~60-70% of cases), it is statistically less frequent than headaches. * **B. Palpitations:** These occur in about 50-70% of patients due to the chronotropic effects of catecholamines on the heart, but they rank below headaches in prevalence. * **C. Diarrhea:** This is not a typical feature. In fact, catecholamines usually cause **constipation** due to the relaxation of gastrointestinal smooth muscle and contraction of sphincters. Diarrhea is more characteristic of Medullary Thyroid Carcinoma (as part of MEN 2 syndrome) due to calcitonin secretion. **Clinical Pearls for NEET-PG:** * **The Rule of 10s:** 10% are bilateral, 10% are extra-adrenal (Paragangliomas), 10% are malignant, and 10% are familial. * **Most Common Sign:** Sustained or paroxysmal **Hypertension** is the most common clinical *sign*. * **Diagnosis:** Best initial screening test is **24-hour urinary fractionated metanephrines** or plasma free metanephrines. * **Management:** Always start **Alpha-blockers (Phenoxybenzamine)** before Beta-blockers to prevent an unopposed alpha-adrenergic hypertensive crisis.

Q: A 50-year-old man reports experiencing transient episodes of rapid heart beat accompanied by sweating, flushing, and a sense of impending doom. Physical examination is normal, with no evidence of arrhythmia during the examination. During one of these episodes, his wife, a nurse, documented a blood pressure of 195/140 mmHg and a heart rate of 160 beats/min. The episode resolved before he could be evaluated. Which of the following urinary measurements would be most useful for diagnosis?

Vanillylmandelic acid (VMA). ### Explanation **Diagnosis: Pheochromocytoma** The clinical presentation of paroxysmal hypertension, tachycardia, diaphoresis, flushing, and a "sense of impending doom" (panic-like symptoms) is a classic triad for **Pheochromocytoma**. This is a catecholamine-secreting tumor arising from chromaffin cells of the adrenal medulla. **1. Why Vanillylmandelic acid (VMA) is the correct answer:** Catecholamines (epinephrine and norepinephrine) are metabolized into metanephrines and subsequently into **Vanillylmandelic acid (VMA)** [1]. In a patient with episodic hypertension, measuring the 24-hour urinary excretion of VMA or metanephrines is a standard biochemical screening tool [1]. VMA is the end-stage metabolite excreted in the urine, making it a highly specific marker for catecholamine excess [1]. **2. Why the other options are incorrect:** * **A. DHEA:** An androgen precursor produced by the adrenal cortex [2]. It is used to evaluate adrenal tumors causing virilization, not paroxysmal hypertension. * **B. hCG:** A hormone produced during pregnancy or by certain germ cell tumors; it has no relevance to sympathetic overactivity. * **C. 17-ketosteroids:** These are metabolites of androgens (like DHEA and androstenedione) [2]. They are used to assess adrenal cortical function, not the adrenal medulla. **3. NEET-PG High-Yield Pearls:** * **Rule of 10s:** 10% are bilateral, 10% are extra-adrenal (Paragangliomas), 10% are malignant, and 10% occur in children. * **Best Initial Test:** Plasma free metanephrines (highest sensitivity). * **Confirmatory Test:** 24-hour urinary metanephrines and VMA (highest specificity). * **Pre-operative Management:** Always give **Alpha-blockers first** (e.g., Phenoxybenzamine) followed by Beta-blockers. Giving a Beta-blocker first can lead to an unopposed alpha-adrenergic crisis. * **Associated Syndromes:** MEN 2A, MEN 2B, von Hippel-Lindau (VHL), and NF-1 [1].

Q: What is the drug of choice for acute adrenal insufficiency?

IV hydrocortisone. Explanation: Acute adrenal insufficiency (Adrenal Crisis) is a medical emergency characterized by a severe deficiency of cortisol and, often, aldosterone. The primary goal of treatment is rapid replacement of glucocorticoids and volume resuscitation. Why IV Hydrocortisone is the Correct Answer: Hydrocortisone is the drug of choice because it possesses both glucocorticoid and mineralocorticoid activity in a 1:1 ratio. In an acute crisis, the patient lacks both hormones; hydrocortisone effectively replaces cortisol while providing sufficient sodium-retaining (aldosterone-like) effects at high doses (usually 100mg IV bolus followed by 200mg/24h). Its rapid onset and balanced profile make it the gold standard. Analysis of Incorrect Options: * A. Oral Prednisone: In an acute crisis, patients are often hemodynamically unstable, vomiting, or obtunded. Oral administration is unreliable and too slow for emergency stabilization. * C. IV Betamethasone: This is a potent long-acting glucocorticoid with zero mineralocorticoid activity. It is primarily used for fetal lung maturity, not adrenal replacement. * D. IV Dexamethasone: While dexamethasone is potent, it lacks mineralocorticoid activity. It is only preferred if a Short Synacthen (ACTH) test needs to be performed immediately, as dexamethasone does not cross-react with cortisol assays, unlike hydrocortisone [1]. High-Yield Clinical Pearls for NEET-PG: * Initial Management: Start IV fluids (Normal Saline) and IV Hydrocortisone immediately; do not wait for laboratory confirmation if the clinical suspicion is high [1]. * Electrolyte Pattern: Look for Hyponatremia, Hyperkalemia, and Hypoglycemia in the question stem. * Maintenance: Once the patient is stable, mineralocorticoid replacement (Fludrocortisone) is added only when the hydrocortisone dose is tapered below 50mg/day.

Question 1

A 25-year-old female presents with a 12-month history of palpitations, intermittent diarrhea, anxiety, and a 1-month history of "bulging of both eyes." What is the most likely cause of her symptoms?

Accepted Answer

Graves' disease

Answer

Hashimoto's thyroiditis

Answer

Multinodular toxic goiter

Answer

Papillary carcinoma

Question 2

Hypothyroidism caused by a viral infection of the thyroid gland is a pathologic condition associated with which of the following blood hormone levels?

Accepted Answer

High TSH

Answer

High prolactin (PRL)

Answer

High cortisol

Answer

Low growth hormone (GH)

Question 3

Which type of diabetes is characterized by impaired glucose-induced insulin secretion with preserved beta-cell mass?

Accepted Answer

Maturity-onset diabetes of the young (MODY)

Answer

Wolfram syndrome

Answer

Type 1 diabetes

Answer

Latent autoimmune diabetes in adults (LADA)

Question 4

Osteitis fibrosa cystica refers to:

Accepted Answer

Hyperparathyroidism.

Answer

Paget's disease.

Answer

Fibrous dysplasia.

Answer

Osteogenesis imperfecta.

Question 5

Which of the following is not a characteristic feature of Multiple Endocrine Neoplasia type 1 (MEN1)?

Accepted Answer

Posterior pituitary tumors

Answer

Foregut carcinoids

Answer

Parathyroid hyperplasia

Answer

Pancreatic neuroendocrine tumors

Question 6

A 53-year-old man with gout, experiencing 4-5 attacks per year and treated with NSAIDs without prophylaxis, presents with tophaceous deposits on his left hand. Screening for renal complications of chronic gout is performed. Which of the following findings is most likely compatible with chronic gouty nephropathy?

Accepted Answer

Decreased urinary concentrating ability and proteinuria

Answer

Nephrotic syndrome

Answer

Acute kidney injury

Answer

Acute tubular necrosis (ATN)

Question 7

Which statement is not true regarding hypocalcemia?

Accepted Answer

Inverse relation with magnesium levels

Answer

Can occur in hypoparathyroidism

Answer

Latent tetany is seen

Answer

Prolonged QT interval is seen

Question 8

Which is the most common clinical feature of pheochromocytoma?

Accepted Answer

Headaches

Answer

Profuse sweating

Answer

Palpitations

Answer

Diarrhea

Question 9

A 50-year-old man reports experiencing transient episodes of rapid heart beat accompanied by sweating, flushing, and a sense of impending doom. Physical examination is normal, with no evidence of arrhythmia during the examination. During one of these episodes, his wife, a nurse, documented a blood pressure of 195/140 mmHg and a heart rate of 160 beats/min. The episode resolved before he could be evaluated. Which of the following urinary measurements would be most useful for diagnosis?

Accepted Answer

Vanillylmandelic acid (VMA)

Answer

Dehydroepiandrosterone (DHEA)

Answer

Human chorionic gonadotropin (hCG)

Answer

17-ketosteroids

Question 10

What is the drug of choice for acute adrenal insufficiency?

Accepted Answer

IV hydrocortisone

Answer

Oral prednisone

Answer

IV betamethasone

Answer

IV dexamethasone

Endocrinology — MCQs

Endocrinology — MCQs

On this page

Practice by Chapter

Want unlimited practice?