Endocrinology Practice Questions

Q: Casal's necklace is a feature of which condition?

Pellagra. **Explanation:** **Casal’s necklace** is a pathognomonic dermatological sign of **Pellagra**, a systemic disease caused by a deficiency of **Niacin (Vitamin B3)** or its precursor, the amino acid **Tryptophan** [1]. The condition is classically characterized by the "4 Ds": Dermatitis, Diarrhea, Dementia, and, if untreated, Death [1], [2]. The dermatitis in Pellagra is typically photosensitive [3]. Casal’s necklace refers to a well-demarcated, erythematous, scaly rash that forms a ring-like distribution around the lower neck and upper chest (the C3-C4 dermatome area exposed to sunlight) [2]. **Analysis of Incorrect Options:** * **Addison Disease:** Characterized by hyperpigmentation due to increased ACTH levels, but it typically involves skin creases, pressure points, and mucous membranes (buccal mucosa) rather than a specific necklace-like photosensitive rash. * **Dermatomyositis:** Features a **"V-sign"** (rash on the chest) and **"Shawl sign"** (rash on the back/shoulders), along with Gottron papules and Heliotrope rash, but these are distinct from the specific hyperkeratotic, pigmented necklace of Pellagra. * **Systemic Lupus Erythematosus (SLE):** Classically presents with a **Malar (butterfly) rash** sparing the nasolabial folds [3]. While photosensitive, it does not present as Casal’s necklace. **High-Yield Clinical Pearls for NEET-PG:** * **Hartnup Disease:** A genetic disorder of tryptophan transport that can present with Pellagra-like symptoms. * **Carcinoid Syndrome:** Can lead to Pellagra because dietary tryptophan is diverted to produce massive amounts of Serotonin instead of Niacin. * **Dietary Link:** Pellagra is common in populations where **maize (corn)** is the staple food, as the niacin in maize is bound (niacytin) and unavailable for absorption unless treated with alkali.

Q: Which of the following malignancies most frequently causes hypercalcemia, except?

Head and Neck. **Explanation:** Hypercalcemia of malignancy (HCM) is the most common cause of hypercalcemia in hospitalized patients [1]. It occurs via three main mechanisms: secretion of **PTH-related peptide (PTHrP)** [2], local osteolytic bone destruction, or 1,25-dihydroxyvitamin D production. The correct answer is **Head and Neck** because, while squamous cell carcinomas of the head and neck frequently cause hypercalcemia via PTHrP, they are statistically less common causes compared to the other options listed. In clinical practice and standard textbooks (like Harrison’s), the most frequent malignancies associated with hypercalcemia are **Lung (specifically Squamous Cell), Breast, and Multiple Myeloma.** [1] **Analysis of Options:** * **Lung (Option C):** Squamous cell carcinoma of the lung is the most common cause of Humoral Hypercalcemia of Malignancy (HHM) due to PTHrP secretion [2]. * **Breast (Option A):** Breast cancer is a very frequent cause, often through a combination of local osteolytic bone metastases and PTHrP production [1], [2]. * **Kidney (Option B):** Renal cell carcinoma is a classic producer of PTHrP and is a frequent cause of HHM [1], [2]. * **Head and Neck (Option D):** While these cancers do cause hypercalcemia, they are ranked lower in overall frequency compared to the high prevalence of Lung and Breast cancers. **NEET-PG High-Yield Pearls:** 1. **Most common cause of hypercalcemia overall:** Primary Hyperparathyroidism (outpatient) [1]. 2. **Most common cause of hypercalcemia in hospitalized patients:** Malignancy [1]. 3. **Most common mechanism of HCM:** PTHrP secretion (80% of cases) [2]. 4. **Multiple Myeloma:** Causes hypercalcemia via local osteolysis (RANKL-mediated) rather than PTHrP [1]. 5. **Treatment of choice for acute severe HCM:** Aggressive IV hydration with normal saline, followed by IV Bisphosphonates (Zoledronic acid).

Q: Obesity is not a feature of which of the following conditions?

Adrenal insufficiency. ### Explanation The correct answer is **Adrenal insufficiency**. **1. Why Adrenal Insufficiency is the correct answer:** Adrenal insufficiency (Addison’s disease) is characterized by a deficiency of cortisol and, in primary cases, aldosterone [1]. Cortisol is a glucocorticoid essential for metabolic homeostasis. Its absence leads to decreased gluconeogenesis and increased insulin sensitivity, often resulting in **weight loss** and anorexia rather than obesity. Weight loss is a hallmark clinical feature of chronic adrenal insufficiency, often accompanied by hyperpigmentation (in primary cases) and hypotension. **2. Why the other options are incorrect:** * **Hypothyroidism:** Low levels of thyroid hormones (T3/T4) lead to a decreased Basal Metabolic Rate (BMR) and accumulation of glycosaminoglycans (myxedema), which causes fluid retention and weight gain. * **Hypogonadism:** Testosterone and estrogen play roles in body fat distribution and muscle mass. Deficiency in these hormones (especially testosterone in males) leads to increased adiposity and decreased lean body mass. * **Cushing’s Syndrome:** This is characterized by chronic glucocorticoid excess [3]. It causes "centripetal obesity" (trunk, buffalo hump, and moon facies) due to the redistribution of fat and stimulation of adipogenesis [3]. **3. NEET-PG High-Yield Pearls:** * **Weight Loss Triad in Endocrinology:** Adrenal insufficiency, Hyperthyroidism, and Type 1 Diabetes Mellitus. * **Secondary Adrenal Insufficiency:** Unlike primary Addison’s, there is **no hyperpigmentation** (due to low ACTH) and **no mineralocorticoid deficiency** (regulated by the RAAS, not ACTH) [2]. * **Cushing’s vs. Simple Obesity:** In Cushing’s, the obesity is typically "central" with thin extremities (due to muscle wasting), whereas simple obesity is usually generalized [3].

Q: Which of the following is NOT true of de Quervain's thyroiditis?

Increased radioactive iodine uptake. De Quervain’s thyroiditis (also known as **Subacute Granulomatous Thyroiditis**) is a self-limiting inflammatory condition of the thyroid, typically following a viral upper respiratory tract infection. **Why Option C is the correct answer:** In de Quervain's thyroiditis, the inflammation causes the **destruction of thyroid follicles**, leading to the leakage of preformed thyroid hormones into the bloodstream (thyrotoxic phase). Because the follicular cells are damaged and inflamed, they are unable to actively trap iodine [1]. Therefore, the **Radioactive Iodine Uptake (RAIU) is characteristically low (<5%)**, despite the patient appearing clinically hyperthyroid [1][2]. This "diagnostic dissociation" (high T3/T4 with low RAIU) is a hallmark of the disease. **Why the other options are incorrect:** * **A. Pain:** This is the most characteristic clinical feature. Patients present with severe pain in the anterior neck that may radiate to the jaw or ears [1]. * **B. Increased ESR:** As an inflammatory condition, the Erythrocyte Sedimentation Rate (ESR) is typically markedly elevated (often >50–100 mm/hr), serving as a key diagnostic marker [1]. * **D. Fever:** Systemic symptoms including fever, malaise, and myalgia are common during the acute phase of the illness [1]. **NEET-PG High-Yield Pearls:** * **Etiology:** Post-viral (Coxsackie, Mumps, Adenovirus). * **Pathology:** Giant cells and granulomatous inflammation on biopsy. * **Treatment:** NSAIDs for mild cases; Glucocorticoids (Prednisone) for severe pain [1]. * **Key Distinction:** Unlike Graves' disease (High RAIU), de Quervain's has **Low RAIU**. Unlike painless thyroiditis, de Quervain's is **exquisitely tender**.

Q: A 64-year-old man presents with severe polyuria and polydipsia, consuming 3 to 4 glasses of water and producing over 0.5 liters of urine each hour. After overnight water restriction, the following test results were obtained: Plasma sodium concentration: 155 mEq/L; Urine osmolarity: 90 mOsmol/L; Urine glucose concentration: 0 mg/dL. Which of the following is the most likely diagnosis?

Diabetes insipidus. ### Explanation **1. Why Diabetes Insipidus (DI) is the Correct Answer:** The clinical hallmark of DI is the inability to concentrate urine despite rising plasma osmolality. This patient presents with the classic triad: **polyuria** (>3L/day), **polydipsia**, and **hypernatremia** (155 mEq/L). [4] * **Water Restriction Test:** In a normal individual, water restriction triggers ADH release, leading to concentrated urine. Here, the urine remains significantly dilute (**90 mOsmol/L**), which is far below the normal response (>600 mOsmol/L) and even below the plasma osmolality. [1] * The absence of glycosuria rules out osmotic diuresis from glucose, confirming that the polyuria is due to a lack of ADH effect (either Central or Nephrogenic DI). **2. Why the Other Options are Incorrect:** * **Addison’s Disease:** Typically presents with **hyponatremia** (due to aldosterone deficiency) and hyperkalemia, not hypernatremia and dilute polyuria. [3] * **Fanconi Syndrome:** While it can cause polyuria due to proximal tubule dysfunction, it is characterized by **glycosuria** (at normal blood glucose levels), phosphaturia, and aminoaciduria. This patient has 0 mg/dL urine glucose. * **Diabetes Mellitus:** Causes osmotic diuresis due to hyperglycemia. The urine would show a **high glucose concentration** and a higher osmolarity than 90 mOsmol/L. **3. NEET-PG High-Yield Clinical Pearls:** * **Diagnostic Cut-off:** DI is suspected when urine osmolarity is ** 295 mOsmol/L). [2] * **Differentiation:** To distinguish Central from Nephrogenic DI, administer **Desmopressin (dDAVP)**. A >50% increase in urine osmolarity indicates Central DI; little to no response indicates Nephrogenic DI. [2] * **Common Causes:** Central DI is often post-neurosurgery or idiopathic; Nephrogenic DI is commonly caused by **Lithium** or hypercalcemia. [2]

Q: Which of the following conditions is a common cause of hypercalcemia?

Hyperthyroidism. **Explanation:** Hypercalcemia is a common clinical finding in endocrinology, primarily driven by increased bone resorption or decreased renal excretion [1]. **Why Hyperthyroidism is Correct:** Thyroid hormones (T3 and T4) have a direct stimulatory effect on osteoclasts, leading to increased bone turnover and resorption. In approximately 15-20% of patients with thyrotoxicosis, this accelerated bone breakdown exceeds the rate of bone formation, resulting in mild hypercalcemia [1]. Additionally, the increased calcium load suppresses Parathyroid Hormone (PTH), leading to hypercalciuria. **Analysis of Incorrect Options:** * **A. Adrenocortical insufficiency:** While Addison’s disease can cause hypercalcemia (due to decreased renal calcium clearance and increased bone resorption), it is considered an **uncommon** cause compared to the metabolic impact of hyperthyroidism [1]. * **B. Amyloidosis:** This is a restrictive/infiltrative disease. While it can lead to renal failure (which causes *hypocalcemia* due to phosphate retention and low Vitamin D) [2], it is not a recognized cause of hypercalcemia. * **D. Vitamin C intoxication:** Vitamin C (Ascorbic acid) is not involved in calcium metabolism. It is **Vitamin D** intoxication (increased intestinal absorption) [1] or **Vitamin A** intoxication (increased bone resorption) that causes hypercalcemia. **High-Yield NEET-PG Pearls:** * **Most common cause overall:** Primary Hyperparathyroidism (outpatient) and Malignancy (inpatient) [1]. * **Mnemonic for Hypercalcemia (CHIMPANZEES):** **C**alcium supplements, **H**yperparathyroidism, **I**atrogenic/Immobilization, **M**ilk-alkali syndrome, **P**aget’s disease, **A**ddison’s/Acromegaly, **N**eoplasia, **Z**ollinger-Ellison (MEN1), **E**xcess Vitamin D, **E**xcess Vitamin A, **S**arcoidosis [1]. * **ECG Finding:** Shortened QT interval is the classic sign of hypercalcemia.

Q: All of the following are true about Hypercalcemia, except:

Pamidronate is not effective. ### Explanation **Hypercalcemia** is a common clinical emergency in endocrinology, most frequently caused by primary hyperparathyroidism or malignancy [1]. **Why Option D is the Correct Answer (The False Statement):** **Pamidronate** is a potent intravenous **bisphosphonate** and is highly effective in treating hypercalcemia, especially when associated with malignancy. It works by inhibiting osteoclast-mediated bone resorption [2]. While it takes 48–72 hours to reach its peak effect, it is a cornerstone of long-term calcium stabilization. Therefore, stating it is "not effective" is medically incorrect. **Analysis of Other Options:** * **Options A & B (Management of primary cause):** These are true. Definitive treatment of hypercalcemia always requires addressing the underlying etiology (e.g., parathyroidectomy for adenoma or treating the underlying cancer) [1]. * **Option C (IV fluid with furosemide):** This is a standard initial treatment. **Aggressive hydration with Normal Saline (0.9% NaCl)** is the first step to restore volume and promote urinary calcium excretion [1]. **Furosemide** (a loop diuretic) is added *after* volume resuscitation to further enhance calciuresis and prevent fluid overload. **Clinical Pearls for NEET-PG:** 1. **First-line treatment:** Isotonic saline (Normal Saline) is the most important initial step. 2. **Bisphosphonates:** Zoledronic acid is generally preferred over Pamidronate due to higher potency and shorter infusion time. 3. **Calcitonin:** Used for rapid, short-term reduction of calcium (works within hours) but is limited by **tachyphylaxis** (effect wears off after 48 hours). 4. **Avoid Thiazides:** Thiazide diuretics are contraindicated in hypercalcemia as they increase renal calcium reabsorption. 5. **ECG Finding:** Look for a **shortened QT interval**, a classic sign of hypercalcemia.

Q: Which of the following is seen in Addison's disease?

Hypercalcemia. Addison’s disease (Primary Adrenocortical Insufficiency) results from the destruction of the adrenal cortex, leading to a deficiency of cortisol, aldosterone, and adrenal androgens [1]. **Why Hypercalcemia is correct:** Hypercalcemia is seen in approximately 10–20% of patients with Addison’s disease. The underlying mechanisms include: 1. **Decreased Renal Excretion:** Cortisol normally inhibits renal tubular reabsorption of calcium; its absence leads to increased calcium retention. 2. **Increased Bone Resorption:** Glucocorticoids normally antagonize the effects of Vitamin D; their deficiency leads to increased calcium mobilization from bones. 3. **Hemoconcentration:** Dehydration (due to mineralocorticoid deficiency) leads to a relative increase in serum calcium levels [3]. **Analysis of Incorrect Options:** * **A. Hypernatremia:** Incorrect. Aldosterone deficiency leads to "salt wasting" (loss of sodium in urine), resulting in **Hyponatremia** [1]. * **B. Hypokalemia:** Incorrect. Aldosterone normally promotes potassium excretion. Its absence leads to potassium retention, resulting in **Hyperkalemia** [1]. * **C. Hyperglycemia:** Incorrect. Cortisol is a counter-regulatory hormone that promotes gluconeogenesis. Its deficiency leads to **Hypoglycemia**. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Electrolyte Triad:** Hyponatremia, Hyperkalemia, and Metabolic Acidosis (Non-gap). * **Hyperpigmentation:** Seen only in *Primary* Adrenal Insufficiency due to increased ACTH (which shares a precursor with Melanocyte Stimulating Hormone - POMC) [2]. * **Diagnosis:** The screening test of choice is the **ACTH Stimulation Test** (Cosyntropin test) [2]. * **Hematology:** Patients often show eosinophilia and lymphocytosis.

Question 1

All of the following are true about acromegaly except:

Accepted Answer

Excessive growth occurs before fusion of the epiphyses of the long bones

Answer

Increased IGF-1 levels

Answer

Somatostatin analogues can be used

Answer

Growth hormone levels are increased

Question 2

Casal's necklace is a feature of which condition?

Accepted Answer

Pellagra

Answer

Addison disease

Answer

Dermatomyositis

Answer

Systemic lupus erythematosus (SLE)

Question 3

Which of the following malignancies most frequently causes hypercalcemia, except?

Accepted Answer

Head and Neck

Answer

Breast

Answer

Kidney

Answer

Lung

Question 4

Obesity is not a feature of which of the following conditions?

Accepted Answer

Adrenal insufficiency

Answer

Hypothyroidism

Answer

Hypogonadism

Answer

Cushing's syndrome

Question 5

Which of the following is NOT true of de Quervain's thyroiditis?

Accepted Answer

Increased radioactive iodine uptake

Answer

Pain

Answer

Increased ESR

Answer

Fever

Question 6

A 64-year-old man presents with severe polyuria and polydipsia, consuming 3 to 4 glasses of water and producing over 0.5 liters of urine each hour. After overnight water restriction, the following test results were obtained: Plasma sodium concentration: 155 mEq/L; Urine osmolarity: 90 mOsmol/L; Urine glucose concentration: 0 mg/dL. Which of the following is the most likely diagnosis?

Accepted Answer

Diabetes insipidus

Answer

Addison's disease

Answer

Fanconi syndrome

Answer

Diabetes mellitus

Question 7

Which of the following conditions is a common cause of hypercalcemia?

Accepted Answer

Hyperthyroidism

Answer

Adrenocortical insufficiency

Answer

Amyloidosis

Answer

Vitamin C intoxication

Question 8

All of the following are true about Hypercalcemia, except:

Accepted Answer

Pamidronate is not effective

Answer

Management of primary cause

Answer

Management of primary cause

Answer

IV fluid with furosemide is given

Question 9

Which of the following is seen in Addison's disease?

Accepted Answer

Hypercalcemia

Answer

Hypernatremia

Answer

Hypokalemia

Answer

Hyperglycemia

Question 10

All of the following are true about Diabetes mellitus EXCEPT:

Accepted Answer

Diabetic ketoacidosis is commoner in type I diabetes mellitus.

Answer

Hyperosmolar hyperglycemic state is primarily seen in individuals with type II diabetes mellitus.

Answer

Serum sodium in diabetic ketoacidosis is typically in the range of 125-135 mEq/L.

Answer

Serum bicarbonate in diabetic ketoacidosis is less than 15 mEq/L.

Endocrinology — MCQs

Endocrinology — MCQs

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