Endocrinology Practice Questions

Q: Which of the following is NOT associated with thymoma?

Hypergammaglobulinemia. **Explanation:** Thymomas are epithelial tumors of the thymus gland, frequently associated with various paraneoplastic syndromes due to the thymus's role in immune self-tolerance. **Why Option C is the correct answer:** Thymoma is characteristically associated with **Hypogammaglobulinemia** (specifically **Good Syndrome**), not hypergammaglobulinemia. Good Syndrome is a rare immunodeficiency characterized by thymoma, low B-cell counts, and low serum immunoglobulin levels, leading to increased susceptibility to infections. **Analysis of Incorrect Options:** * **Option A (Red cell aplasia):** Pure Red Cell Aplasia (PRCA) is a well-known paraneoplastic manifestation of thymoma. Approximately 5-15% of patients with PRCA have a thymoma, and surgical removal of the tumor can sometimes lead to hematologic remission. * **Option B (Myasthenia gravis):** This is the most common association [1]. About 30-45% of patients with thymoma have Myasthenia Gravis (MG), and conversely, 10-15% of patients with MG are found to have a thymoma [1]. * **Option D (Compression of the mediastinum):** As thymomas are anterior mediastinal masses, they can grow large enough to cause local "mass effect" symptoms, including superior vena cava (SVC) syndrome, cough, dyspnea, and chest pain. **High-Yield Clinical Pearls for NEET-PG:** * **Good Syndrome:** Thymoma + Hypogammaglobulinemia + Low B-cells. * **Most common anterior mediastinal mass:** Thymoma (in adults). * **The "4 Ts" of Anterior Mediastinal Masses:** Thymoma, Teratoma (Germ cell tumors), Thyroid (Retrosternal goiter), and "Terrible" Lymphoma. * **Diagnosis:** Contrast-enhanced CT (CECT) is the imaging modality of choice [1].

Q: In phaeochromocytoma, what substance will be present in elevated amounts in the urine?

Vanillylmandelic acid (VMA). PHAEOCROMOCYTOMA EXPLANATION: **1. Why Vanillylmandelic acid (VMA) is correct:** Pheochromocytoma is a catecholamine-secreting tumor arising from the chromaffin cells of the adrenal medulla [1]. These tumors overproduce epinephrine and norepinephrine. These catecholamines are metabolized by enzymes (COMT and MAO) into intermediate metabolites called **metanephrines** and finally into the end-product, **Vanillylmandelic acid (VMA)**. Because these substances are excreted by the kidneys, elevated levels of urinary VMA (measured via a 24-hour urine collection) serve as a classic biochemical marker for diagnosing pheochromocytoma. **2. Why the other options are incorrect:** * **5-hydroxyindoleacetic acid (5-HIAA):** This is the primary metabolite of **serotonin**. It is the gold-standard urinary marker for **Carcinoid Syndrome**, not pheochromocytoma. * **Option C & D:** Since VMA is specific to catecholamine metabolism and 5-HIAA is specific to serotonin metabolism, they represent two distinct clinical entities. **3. NEET-PG High-Yield Clinical Pearls:** * **Best Initial Screening Test:** Plasma free metanephrines (highest sensitivity). * **Confirmatory Test:** 24-hour urinary metanephrines and VMA (high specificity). * **Rule of 10s:** 10% are bilateral, 10% are malignant, 10% are extra-adrenal (Paragangliomas), and 10% occur in children [1]. * **Clinical Triad:** Episodic headache, sweating (diaphoresis), and tachycardia/palpitations in a hypertensive patient. * **Pre-operative Management:** Always give **Alpha-blockers first** (e.g., Phenoxybenzamine) followed by Beta-blockers to prevent a hypertensive crisis.

Q: Which one of the following is not a feature of Klinefelter's syndrome?

Short 4th metacarpal. **Explanation:** **Klinefelter’s Syndrome (47, XXY)** is the most common cause of primary hypogonadism in males. [1] The correct answer is **Short 4th metacarpal**, as this is a classic clinical feature of **Turner’s Syndrome (45, XO)** and Pseudohypoparathyroidism, not Klinefelter’s. [2] **Analysis of Options:** * **Short 4th metacarpal (Correct Answer):** Also known as **Archibald’s sign**, this is a skeletal deformity associated with Turner’s syndrome. [2] In Klinefelter’s, skeletal findings typically involve increased limb length rather than shortening of metacarpals. [1] * **Gynecomastia:** Present in approximately 40-50% of cases due to an increased estrogen-to-androgen ratio. It also carries a significantly higher risk of male breast cancer. [3] * **Eunuchoid habitus:** Characterized by tall stature, long legs (lower segment > upper segment), and a decreased arm span-to-height ratio. [1] This occurs because testosterone deficiency leads to delayed epiphyseal closure. * **Hypogonadism:** Patients exhibit primary testicular failure characterized by small, firm testes (usually <2 cm), azoospermia (infertility), and low testosterone levels with compensatory elevations in LH and FSH. [1] **High-Yield Clinical Pearls for NEET-PG:** * **Karyotype:** Most commonly 47, XXY due to meiotic non-disjunction. * **Histology:** Testicular biopsy shows **hyalinization and fibrosis of seminiferous tubules** and Leydig cell hyperplasia. [1] * **Lab Findings:** ↓ Testosterone, ↑ FSH, ↑ LH, ↑ Estradiol. [1] * **Associated Risks:** Increased risk of Germ Cell Tumors (especially mediastinal), Breast Cancer, and autoimmune diseases (SLE). [3] * **Psychosocial:** Often associated with mild intellectual disability or learning delays. [1]

Q: The classic triad of pheochromocytoma includes episodes of all of the following except:

Hypertension. The correct answer is **Hypertension**. ### **Explanation** While **hypertension** is the most common clinical sign of pheochromocytoma (present in >90% of cases), it is **not** part of the "classic symptomatic triad." The triad refers specifically to the paroxysmal symptoms experienced by the patient during a catecholamine surge. The classic clinical triad consists of: 1. **Headache** (most common symptom) 2. **Sweating** (diaphoresis) 3. **Palpitations** (tachycardia) The presence of all three symptoms plus hypertension has a specificity of over 90% for pheochromocytoma. However, because hypertension is a physical finding (sign) rather than a symptom in the triad, it is the "except" in this question. ### **Analysis of Options** * **A, B, and C (Palpitations, Headache, Sweating):** These constitute the classic triad. They occur in paroxysms ("spells") due to the episodic release of epinephrine and norepinephrine from the adrenal medulla tumor. * **D (Hypertension):** Although it is the most common feature, it is categorized as a **clinical sign**. Hypertension in pheochromocytoma can be sustained (60%) or paroxysmal (40%). ### **NEET-PG High-Yield Pearls** * **Rule of 10s:** 10% bilateral, 10% malignant, 10% pediatric, 10% extra-adrenal (Paraganglioma), and 10% familial. * **Best Screening Test:** Plasma free metanephrines (high sensitivity). * **Best Confirmatory Test:** 24-hour urinary fractionated metanephrines and catecholamines (high specificity). * **Pre-operative Management:** Always give **Alpha-blockers first** (e.g., Phenoxybenzamine) followed by Beta-blockers to avoid a hypertensive crisis (unopposed alpha-stimulation). * **Genetic Associations:** MEN 2A, MEN 2B, VHL syndrome, and NF-1.

Q: Which of the following statements regarding the lipid abnormalities seen in patients with type 2 diabetes mellitus is incorrect?

Elevated levels of plasma LDL cholesterol. The characteristic pattern of dyslipidemia in Type 2 Diabetes Mellitus (T2DM) is known as "Diabetic Dyslipidemia." It is primarily driven by insulin resistance rather than a simple elevation of total cholesterol. In T2DM, the absolute level of LDL cholesterol is typically not significantly elevated compared to the general population. Instead, the abnormality lies in the quality of the LDL particles. Due to high triglyceride levels, LDL particles undergo remodeling to become small, dense LDL (sdLDL) [1]. These particles are more atherogenic because they easily penetrate the arterial wall and are more susceptible to oxidation [1]. Insulin resistance leads to increased lipolysis in adipose tissue, flooding the liver with free fatty acids [3]. This stimulates the overproduction of VLDL (rich in triglycerides), leading to hypertriglyceridemia [1]. High VLDL levels trigger an exchange where HDL loses cholesterol and gains triglycerides via CETP [1]. These triglyceride-rich HDL particles are rapidly cleared by hepatic lipase, resulting in low plasma HDL levels [1]. Reduced activity of Lipoprotein Lipase (LPL) in insulin-deficient states contributes to decreased clearance of VLDL and chylomicrons [2].

Q: Which condition can cause profound hyperlipidemia?

Hypothyroidism. **Explanation:** **Hypothyroidism** is a classic cause of secondary hyperlipidemia. Thyroid hormones play a critical role in lipid metabolism by upregulating the expression of **LDL receptors** on hepatocytes [1]. In a hypothyroid state, the decrease in thyroid hormones leads to a reduced number of LDL receptors, resulting in decreased clearance of LDL-cholesterol from the plasma. Additionally, hypothyroidism decreases the activity of **lipoprotein lipase (LPL)** and slows the oxidative metabolism of cholesterol into bile acids, leading to profound elevations in total cholesterol and LDL levels. **Analysis of Incorrect Options:** * **Hyperinsulinemia (Option A):** While insulin resistance is associated with metabolic syndrome and dyslipidemia (high triglycerides, low HDL), acute hyperinsulinemia typically promotes lipid storage and inhibits lipolysis [2]. * **Hyperparathyroidism (Option B):** This condition primarily affects calcium and phosphate homeostasis. It does not have a direct, significant impact on lipid profiles. * **Hyperthyroidism (Option D):** Excess thyroid hormone increases the expression of LDL receptors and accelerates cholesterol metabolism [1]. Consequently, hyperthyroidism typically causes **hypocholesterolemia**. **NEET-PG High-Yield Pearls:** * **Type IIb Hyperlipidemia:** Hypothyroidism most commonly presents as an elevation in LDL (Type IIa), but can also cause a mixed picture (Type IIb) with elevated VLDL. * **Statin Warning:** Always check TSH levels before starting a patient on statins. Hypothyroidism predisposes patients to **statin-induced myopathy** and rhabdomyolysis [2]. * **Other Secondary Causes:** Nephrotic syndrome (causes profound hypercholesterolemia), Obstructive jaundice, and Diabetes Mellitus.

Q: Doughy skin and woody induration of the tongue are seen in which of the following conditions?

Hypernatremia. **Explanation:** **Hypernatremia** (Option B) represents a state of hyperosmolality, typically due to a deficit in total body water relative to sodium. When serum sodium levels rise, water is drawn out of the intracellular and interstitial compartments into the intravascular space to maintain osmotic balance [1]. This profound cellular dehydration leads to characteristic physical findings: * **Doughy Skin:** Unlike the "tenting" seen in simple dehydration, the skin in hypernatremia feels thick and "doughy" due to the loss of intracellular water while maintaining some interstitial volume. * **Woody Induration of the Tongue:** The tongue becomes dry, shriveled, and firm (woody) due to extreme mucosal dehydration. **Incorrect Options:** * **Hyponatremia (A):** Typically presents with signs of cerebral edema (headache, seizures, coma) due to water moving *into* cells [1]. Skin turgor may be decreased if it is hypovolemic hyponatremia, but it does not produce the "doughy" texture. * **Hypokalemia (C) & Hyperkalemia (D):** Potassium imbalances primarily affect neuromuscular and cardiac conduction [2]. Clinical features include muscle weakness, ileus, or arrhythmias, but they do not significantly alter skin or tongue consistency. **Clinical Pearls for NEET-PG:** * **Adipsic Hypernatremia:** Often seen in elderly patients with a diminished thirst mechanism or hypothalamic lesions [2]. * **Correction Rate:** In chronic hypernatremia, the brain produces **idiogenic osmoles** to prevent shrinkage. Rapid correction can lead to **Cerebral Edema**. The goal is to lower sodium by no more than 10–12 mEq/L in 24 hours [1]. * **Key Association:** Always look for "doughy skin" in pediatric cases of severe dehydration or patients with Diabetes Insipidus.

Question 1

Which of the following is NOT associated with thymoma?

Accepted Answer

Hypergammaglobulinemia

Answer

Red cell aplasia

Answer

Myasthenia gravis

Answer

Compression of the mediastinum

Question 2

In phaeochromocytoma, what substance will be present in elevated amounts in the urine?

Accepted Answer

Vanillylmandelic acid (VMA)

Answer

5-hydroxyindoleacetic acid (HIAA)

Answer

Both VMA and HIAA

Answer

Neither VMA nor HIAA

Question 3

Which one of the following is not a feature of Klinefelter's syndrome?

Accepted Answer

Short 4th metacarpal

Answer

Gynecomastia

Answer

Eunuchoid habitus

Answer

Hypogonadism

Question 4

The classic triad of pheochromocytoma includes episodes of all of the following except:

Accepted Answer

Hypertension

Answer

Palpitations

Answer

Headache

Answer

Sweating

Question 5

Which of the following statements regarding the lipid abnormalities seen in patients with type 2 diabetes mellitus is incorrect?

Accepted Answer

Elevated levels of plasma LDL cholesterol

Answer

Increase in hepatic VLDL production

Answer

Decrease in plasma levels of HDL cholesterol

Answer

Elevated plasma triglycerides

Question 6

Bronze diabetes is seen in which of the following conditions?

Accepted Answer

Hemochromatosis

Answer

Wilson's disease

Answer

Sarcoidosis

Answer

Lead intoxication

Question 7

All of the following can commonly occur in a patient who suffered a decelerating injury with damaged pituitary stalk, except one?

Accepted Answer

Diabetes mellitus

Answer

Thyroid insufficiency

Answer

Adrenocortical insufficiency

Answer

Diabetes insipidus

Question 8

An 18-year-old girl presents with hypertension, a masculine body, and clitoromegaly. Which of the following conditions causes hyperandrogenism and hypertension?

Accepted Answer

11-hydroxylase deficiency

Answer

17 beta hydroxylase deficiency

Answer

Turner syndrome

Answer

Rett syndrome

Question 9

Which condition can cause profound hyperlipidemia?

Accepted Answer

Hypothyroidism

Answer

Hyperinsulinemia

Answer

Hyperparathyroidism

Answer

Hyperthyroidism

Question 10

Doughy skin and woody induration of the tongue are seen in which of the following conditions?

Accepted Answer

Hypernatremia

Answer

Hyponatremia

Answer

Hypokalemia

Answer

Hyperkalemia

Endocrinology — MCQs

Endocrinology — MCQs

On this page

Practice by Chapter

Want unlimited practice?