Endocrinology Practice Questions

Q: What is a subtle presentation of hyperparathyroidism?

Asymptomatic hypercalcemia. **Explanation:** Primary Hyperparathyroidism (PHPT) is most commonly caused by a solitary parathyroid adenoma. In the modern era of routine biochemical screening, the clinical profile of the disease has shifted significantly. **Why D is the correct answer:** **Asymptomatic hypercalcemia** is now the most common presentation of PHPT (found in >80% of cases). Most patients are identified incidentally during routine blood tests (e.g., a comprehensive metabolic panel) showing elevated serum calcium and inappropriately high or normal PTH levels. These patients lack the classic "bones, stones, abdominal groans, and psychic moans" and are clinically "subtle" or asymptomatic. **Why other options are incorrect:** * **B (Nephrocalcinosis) & C (Abdominal pain):** These represent the "Stones" and "Groans" of the classic tetrad. Nephrocalcinosis and peptic ulcer disease/pancreatitis are late-stage, overt complications of chronic, severe hypercalcemia, rather than subtle presentations. * **A (Psychiatric manifestation):** Known as "Psychic moans" (depression, fatigue, or confusion), these occur in symptomatic disease. While they can be vague, they are considered part of the established clinical syndrome rather than the most common subtle finding. **NEET-PG High-Yield Pearls:** * **Most common cause:** Solitary Adenoma (85-90%). * **Classic X-ray finding:** Subperiosteal bone resorption (most common in the radial aspect of middle phalanges) and "Salt and pepper" skull. * **Brown Tumors:** Also known as Osteitis Fibrosa Cystica; these are non-neoplastic lesions due to increased osteoclast activity. * **Biochemical Hallmark:** ↑ Serum Calcium, ↓ Serum Phosphate, ↑ PTH, and ↑ Urinary cAMP. * **Hungry Bone Syndrome:** A common post-operative complication after parathyroidectomy characterized by severe hypocalcemia.

Q: Which of the following tests is best for differentiating an ACTH-secreting pituitary tumor from ectopic ACTH production?

High-dose dexamethasone suppression test. ### Explanation The diagnostic approach to Cushing’s syndrome follows a stepwise protocol: first, confirming hypercortisolism, and second, determining the etiology (ACTH-dependent vs. independent) [1]. **Why Option D is Correct:** The **High-Dose Dexamethasone Suppression Test (HDDST)** is used to differentiate between ACTH-dependent causes [3]. Pituitary adenomas (Cushing’s Disease) retain some degree of negative feedback sensitivity. Therefore, a high dose of dexamethasone (8 mg) is sufficient to suppress cortisol levels (usually by >50%). In contrast, **Ectopic ACTH production** (e.g., small cell lung cancer) is autonomous and does not respond to negative feedback, resulting in no cortisol suppression. **Why Other Options are Incorrect:** * **Options A, B, and C:** These are **screening tests** used to establish the diagnosis of Cushing’s syndrome (hypercortisolism) [1]. They cannot differentiate the source of ACTH [2]. * **24-hour Urinary Free Cortisol (UFC):** Measures integrated cortisol excretion [1]. * **Overnight/Low-Dose DST (LDDST):** Demonstrates the loss of normal negative feedback; failure to suppress cortisol confirms Cushing’s syndrome but not the cause [1]. **NEET-PG High-Yield Pearls:** * **Gold Standard:** The most accurate test to differentiate pituitary vs. ectopic ACTH is **Inferior Petrosal Sinus Sampling (IPSS)** with CRH stimulation. * **CRH Stimulation Test:** Pituitary tumors respond with a rise in ACTH/cortisol; ectopic sources do not. * **Imaging:** Once HDDST suggests a pituitary source, an MRI brain is the next step [3]. If it suggests ectopic, CT Chest/Abdomen is indicated. * **Classic Association:** Ectopic ACTH is frequently associated with profound hypokalemia and very high hyperpigmentation compared to Cushing’s disease.

Q: A 31-year-old woman presents with new-onset headaches and elevated blood pressure. She also reports episodic symptoms including palpitations, anxiety, and marked blood pressure elevation. Workup for secondary causes of hypertension reveals elevated urinary free catecholamines. What is the typical cardiovascular involvement in a patient with this systemic disease?

Focal myocardial necrosis. The clinical presentation of episodic hypertension, palpitations, anxiety, and elevated urinary catecholamines is classic for **Pheochromocytoma**. This catecholamine-secreting tumor (usually of the adrenal medulla) leads to significant cardiovascular morbidity. **1. Why Focal Myocardial Necrosis is correct:** Chronic or paroxysmal exposure to high levels of circulating catecholamines (epinephrine and norepinephrine) causes direct toxic effects on the myocardium. This leads to **"Catecholamine Myocarditis,"** characterized by focal myocardial necrosis, mononuclear cell infiltration, and interstitial fibrosis. This damage can manifest as Takotsubo-like cardiomyopathy, arrhythmias, or congestive heart failure. **2. Why the other options are incorrect:** * **Proximal aortitis:** This is typically associated with large-vessel vasculitides like Takayasu arteritis or Syphilis, not catecholamine excess. * **Endothelial plaques:** While hypertension accelerates atherosclerosis (plaque formation), it is a chronic, non-specific process [2]. Focal necrosis is the specific, "typical" pathological hallmark of pheochromocytoma-induced heart disease. * **Systolic scratchy sound:** This refers to a pericardial friction rub (pericarditis) or the Hamman sign (pneumomediastinum). Pheochromocytoma does not typically cause pericardial inflammation. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of 10s:** 10% bilateral, 10% malignant, 10% extra-adrenal (Paraganglioma), 10% pediatric, and 10% familial. * **Diagnosis:** Best initial screening test is **Plasma free metanephrines**; most specific is **24-hour urinary metanephrines** [1]. * **Management:** Always start **Alpha-blockers first** (e.g., Phenoxybenzamine) for 10-14 days before Beta-blockers to avoid a hypertensive crisis (unopposed alpha-stimulation) [1]. * **Associated Syndromes:** MEN 2A, MEN 2B, von Hippel-Lindau (VHL), and NF-1.

Q: Which of the following is seen in Vitamin D deficiency?

Increased alkaline phosphatase. Vitamin D deficiency leads to decreased intestinal absorption of calcium and phosphate [1]. This triggers a physiological cascade essential for NEET-PG preparation: 1. **Why Option A is Correct:** Low serum calcium stimulates the parathyroid glands to secrete **Parathyroid Hormone (PTH)** (Secondary Hyperparathyroidism) [2]. PTH increases bone remodeling and osteoblastic activity to mobilize calcium. **Alkaline Phosphatase (ALP)** is a byproduct of osteoblastic activity; therefore, its levels rise significantly as the bone attempts to compensate for the mineral deficit. This is often the earliest biochemical marker of osteomalacia/rickets. 2. **Why Options B and C are Incorrect:** * **Hypophosphatemia (Not Hyperphosphatemia):** While Vitamin D deficiency reduces phosphate absorption, the secondary hyperparathyroidism further worsens this by causing **phosphaturia** (increased phosphate excretion in urine) by inhibiting the sodium-phosphate cotransporter in the proximal tubule [3, 4]. * **Increased Urine Phosphate (Not Decreased):** Due to the action of PTH on the kidneys, phosphate clearance increases, leading to low serum phosphate levels [2]. 3. **Why Option D is Incorrect:** Decreased ALP is rare and seen in conditions like hypophosphatasia or profound malnutrition, whereas Vitamin D deficiency characteristically shows elevated ALP [4]. **High-Yield Clinical Pearls for NEET-PG:** * **Biochemical Profile of Vitamin D Deficiency:** ↓ Serum Calcium (or normal in early stages) [1], ↓ Serum Phosphate, ↑ PTH, and **↑ Alkaline Phosphatase** [4]. * **Urinary Findings:** Increased phosphate and increased cAMP in urine. * **Radiological Sign:** Look for **Looser’s zones** (pseudofractures) in osteomalacia [4] and **cupping/fraying** of metaphyses in rickets [1]. * **Golden Rule:** In any metabolic bone disease involving high bone turnover (except Multiple Myeloma), ALP is typically elevated.

Q: A patient presents with persistent diarrhea and hypotension. What is the most likely diagnosis?

VIPoma. **Explanation:** The clinical presentation of persistent watery diarrhea and hypotension is classic for a **VIPoma**, a rare neuroendocrine tumor (usually pancreatic) that secretes excessive **Vasoactive Intestinal Peptide (VIP)** [1]. **1. Why VIPoma is correct:** VIP stimulates intestinal secretion of water and electrolytes and inhibits gastric acid secretion [1]. This leads to the **WDHA Syndrome**: * **W**atery **D**iarrhea (secretory, persists even during fasting) * **H**ypokalemia (due to fecal potassium loss) * **A**chlorhydria (suppression of gastric acid) The profound loss of fluids and the potent vasodilatory effect of VIP lead to **hypotension** and dehydration [1]. **2. Why the other options are incorrect:** * **ACTHoma:** Secretes ACTH, leading to Cushing’s syndrome [1]. Typical features include hypertension (not hypotension), central obesity, and hyperglycemia. * **GRFoma:** Secretes Growth Hormone-Releasing Factor, leading to Acromegaly. It does not typically cause acute diarrhea or hypotension. * **Glucagonoma:** Characterized by the "4 Ds": Diabetes, Dermatitis (Necrolytic Migratory Erythema), DVT, and Depression. Diarrhea is less common, and it does not cause hypotension. **3. NEET-PG High-Yield Pearls:** * **Alternative Name:** VIPoma is also known as **Verner-Morrison Syndrome** or **Pancreatic Cholera**. * **Diagnosis:** Elevated fasting serum VIP levels (>200 pg/mL). * **Localization:** Most are found in the tail of the pancreas; 50-70% are metastatic at diagnosis [1]. * **Management:** Initial stabilization requires aggressive fluid resuscitation and **Octreotide** (somatostatin analog) to inhibit VIP release.

Question 1

A 55-year-old diabetic man presents to the emergency room in an unresponsive state. His laboratory values show PCO2 19 mm Hg, HCO3 11 mEq/L, and pH 6.9. What is the most appropriate immediate treatment for this patient?

Accepted Answer

Administration of insulin

Answer

Administration of an oral hypoglycemic agent

Answer

Administration of bicarbonate

Answer

Close observation only

Question 2

What is a subtle presentation of hyperparathyroidism?

Accepted Answer

Asymptomatic hypercalcemia

Answer

Psychiatric manifestation

Answer

Nephrocalcinosis

Answer

Abdominal pain

Question 3

Which of the following tests is best for differentiating an ACTH-secreting pituitary tumor from ectopic ACTH production?

Accepted Answer

High-dose dexamethasone suppression test

Answer

24-hour urinary free cortisol

Answer

Overnight dexamethasone suppression test

Answer

Low-dose dexamethasone suppression test

Question 4

What is true about diabetic nephropathy?

Accepted Answer

Pancreatic transplantation can improve proteinuria in the early stage.

Answer

Microalbuminuria is not an indicator of long-term cardiovascular morbidity.

Answer

Strict glycemic control cannot prevent microalbuminuria.

Answer

Angiotensin receptor blockers have no additive advantage over other drugs except for blood pressure control.

Question 5

A 31-year-old woman presents with new-onset headaches and elevated blood pressure. She also reports episodic symptoms including palpitations, anxiety, and marked blood pressure elevation. Workup for secondary causes of hypertension reveals elevated urinary free catecholamines. What is the typical cardiovascular involvement in a patient with this systemic disease?

Accepted Answer

Focal myocardial necrosis

Answer

Proximal aortitis

Answer

Endothelial plaques

Answer

Systolic scratchy sound

Question 6

If a normal individual receives an insulin injection that lowers plasma glucose to 30 mg/dl, which of the following hormones will NOT be released?

Accepted Answer

Aldosterone

Answer

ACTH

Answer

Epinephrine

Answer

Growth hormone

Question 7

Which of the following is seen in Vitamin D deficiency?

Accepted Answer

Increased alkaline phosphatase

Answer

Decreased phosphate in urine

Answer

Hyperphosphatemia

Answer

Decreased alkaline phosphatase

Question 8

Which condition is characterized by hypocalcemia with hyperphosphatemia?

Accepted Answer

Chronic renal failure (CRF)

Answer

Pseudohypoparathyroidism

Answer

Vitamin D deficiency

Answer

Vitamin D deficiency

Question 9

A patient presents with persistent diarrhea and hypotension. What is the most likely diagnosis?

Accepted Answer

VIPoma

Answer

ACTHoma

Answer

GRFoma

Answer

Glucagonoma

Question 10

A 38-year-old male presents with paroxysmal hypertension. He is subsequently found to have medullary carcinoma of the thyroid, pheochromocytoma, and mucosal neuromas. Parathyroid involvement is not noted. What is the most likely diagnosis?

Accepted Answer

Multiple Endocrine Neoplasia type IIB (MEN IIB)

Answer

Multiple Endocrine Neoplasia type I (MEN I)

Answer

Multiple Endocrine Neoplasia type IIA (MEN IIA)

Answer

Sipple's syndrome

Endocrinology — MCQs

Endocrinology — MCQs

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