Endocrinology Practice Questions

Q: A 50-year-old patient presents with a history of jaw expansion and enlargement of the maxilla. What is the most likely diagnosis?

Paget's disease. **Explanation:** The clinical presentation of jaw expansion and maxillary enlargement in a 50-year-old is a classic hallmark of **Paget’s Disease of Bone (Osteitis Deformans)**. 1. **Why Paget's Disease is Correct:** This condition involves disordered bone remodeling characterized by excessive bone resorption followed by disorganized, exuberant bone formation [1]. While the skull and pelvis are commonly involved, when it affects the facial bones, the **maxilla** is involved much more frequently than the mandible. This leads to widening of the alveolar ridges, spreading of teeth, and a characteristic "lion-like" facies (leontiasis ossea). In older patients, a classic board-style clue is a patient complaining that their "hat no longer fits" or their "dentures have become too tight." 2. **Why the Other Options are Incorrect:** * **Acromegaly:** While it causes bone overgrowth, it characteristically affects the **mandible** (prognathism) rather than the maxilla, leading to an underbite. * **Fibrous Dysplasia:** This typically presents in younger patients (children/adolescents). While it can cause facial asymmetry (especially the monostotic form), the age of 50 makes Paget’s more likely. * **Hyperparathyroidism:** This leads to generalized bone resorption (osteitis fibrosa cystica) and "brown tumors," but it does not typically cause the massive, diffuse expansion of the maxilla seen in Paget’s. **High-Yield Clinical Pearls for NEET-PG:** * **Biochemical Marker:** Isolated elevation of **Alkaline Phosphatase (ALP)** with normal Calcium, Phosphate, and PTH. * **Radiology:** "Cotton wool" appearance of the skull [1]. * **Complications:** High-output heart failure (due to increased vascularity) [1] and Osteosarcoma (rare but serious) [2]. * **Treatment of Choice:** Bisphosphonates (Zoledronic acid).

Q: In a patient, there are elevated plasma cortisol levels. Dexamethasone fails to suppress cortisol secretion. What is the next step in management?

Serum ACTH. This question tests the diagnostic algorithm for **Cushing’s Syndrome**. Once hypercortisolism is confirmed (via 24-hour urinary free cortisol, late-night salivary cortisol, or a low-dose dexamethasone suppression test), the next priority is to determine the **etiology** [1]. ### Why Serum ACTH is the Correct Answer The fundamental step in differentiating the causes of Cushing’s syndrome is determining if the condition is **ACTH-dependent** or **ACTH-independent** [1]. * **Low ACTH ( 15-20 pg/mL):** Suggests an ACTH-dependent cause, such as a pituitary adenoma (Cushing’s Disease) or ectopic ACTH production (e.g., Small Cell Lung Cancer) [1]. Since the patient has failed dexamethasone suppression (confirming hypercortisolism), measuring **Serum ACTH** is the mandatory next step to localize the pathology. ### Why Other Options are Incorrect * **Options B & C (Urinary Metanephrines/VMA):** These are screening tests for **Pheochromocytoma**, not Cushing’s syndrome. While both involve the adrenal gland, they assess the medulla (catecholamines), not the cortex (cortisol). * **Option D (Serum DHEAS):** While DHEAS may be elevated in adrenal carcinomas, it is not a primary step in the diagnostic algorithm for hypercortisolism. ### Clinical Pearls for NEET-PG * **Screening Test:** Overnight Low-Dose Dexamethasone Suppression Test (LDDST). * **Confirmatory Test:** 24-hour Urinary Free Cortisol (UFC). * **Localization Step 1:** Plasma ACTH levels [1]. * **Localization Step 2 (if ACTH is high):** High-Dose Dexamethasone Suppression Test (HDDST) or IPSS (Inferior Petrosal Sinus Sampling) to differentiate Pituitary vs. Ectopic sources. * **Most common cause of Cushing’s Syndrome:** Exogenous steroid use. * **Most common endogenous cause:** Cushing’s Disease (Pituitary adenoma).

Q: Which of the following is NOT a feature of primary thyrotoxicosis?

Intolerance to cold. Explanation: Thyrotoxicosis is a clinical state resulting from inappropriate high levels of circulating thyroid hormones ($T_3$ and $T_4$). Thyroid hormones act as a "metabolic accelerator," increasing the basal metabolic rate (BMR) and upregulating beta-adrenergic receptors [1]. Why "Intolerance to Cold" is the correct answer: Primary thyrotoxicosis leads to increased thermogenesis (heat production). Consequently, patients develop heat intolerance and prefer cold environments [1]. Cold intolerance is a hallmark feature of hypothyroidism, where the BMR is low and the body cannot generate sufficient heat. Analysis of incorrect options: * Tremors: Excess thyroid hormone increases sensitivity to catecholamines and affects the neurological system. This typically manifests as a fine, high-frequency kinetic tremor, best seen in outstretched hands [1]. * Warm extremities: Increased metabolism and the need to dissipate excess heat lead to peripheral vasodilation. This results in skin that is characteristically warm, moist, and velvety [1]. * Diarrhea: Thyroid hormones stimulate gut motility [1]. While frank diarrhea occurs in severe cases, most patients report an increased frequency of bowel movements or malabsorption. Clinical Pearls for NEET-PG: * Apathetic Hyperthyroidism: Seen in the elderly; typical hypermetabolic features (like tremors/tachycardia) may be absent, presenting instead with depression or atrial fibrillation [2]. * Cardiovascular Sign: Look for "bounding pulses" and a wide pulse pressure due to increased stroke volume and decreased peripheral resistance [1]. * Eye Signs: Lid lag and lid retraction are due to sympathetic overactivity (seen in all thyrotoxicosis), whereas Exophthalmos is specific to Graves' Disease (due to TSH-receptor antibodies) [1].

Q: A 67-year-old woman presents to the clinic for evaluation of numbness in her feet, with symptoms that started gradually and are more noticeable now. There is no weakness in her feet or difficulty walking. Her past medical history is significant for Type 2 diabetes for the past 10 years, for which she currently takes metformin and glyburide. Physical examination confirms sensory loss in the feet to touch and vibration. Which of the following is most characteristic of diabetic neuropathy?

It is usually bilateral.. **Explanation:** The patient presents with classic symptoms of **Distal Symmetric Polyneuropathy (DSPN)**, the most common form of diabetic neuropathy [1]. **1. Why Option A is correct:** Diabetic neuropathy is a length-dependent process caused by metabolic and microvascular damage to the nerves [1]. It typically presents in a **"stocking-and-glove" distribution**, meaning it is **bilateral, symmetrical**, and starts in the longest nerves (the feet) [1]. The symmetry is a hallmark feature that helps distinguish it from other conditions like mononeuritis multiplex. **2. Why the other options are incorrect:** * **Option B:** Pain is a very common feature. Up to 50% of patients experience "positive" symptoms such as burning, tingling, or lancinating pain, which is often worse at night. * **Option C:** Diabetic neuropathy primarily affects the **Peripheral Nervous System (PNS)** and the Autonomic Nervous System [1]. It does not typically affect the brain (Central Nervous System). * **Option D:** Diabetes frequently involves the **Autonomic Nervous System**, leading to complications such as resting tachycardia, orthostatic hypotension, gastroparesis, and erectile dysfunction [3]. **Clinical Pearls for NEET-PG:** * **First sign:** Loss of vibratory sensation (tested with a 128-Hz tuning fork) and loss of ankle jerks [1], [2]. * **Screening:** Annual screening using the **10-g Semmes-Weinstein monofilament** is essential to identify feet at risk for ulceration [2]. * **Management:** Strict glycemic control is the only way to prevent progression. For symptomatic pain, first-line agents include **Pregabalin, Duloxetine, or Gabapentin**. * **Metformin Link:** Long-term metformin use (as seen in this patient) can cause **Vitamin B12 deficiency**, which can mimic or exacerbate diabetic neuropathy. Always check B12 levels in these patients.

Q: Which of the following is the most common functioning pancreatic islet cell tumor?

Insulinoma. **Explanation:** **Insulinoma** is the most common functioning pancreatic neuroendocrine tumor (pNET). These tumors arise from the beta cells of the pancreatic islets and are characterized by the autonomous secretion of insulin, leading to fasting hypoglycemia [1]. **Why Insulinoma is correct:** Statistically, insulinomas represent the most frequent functioning pNET [2]. Clinically, they present with the **Whipple Triad**: symptoms of hypoglycemia, low blood glucose levels (<50 mg/dL), and immediate relief of symptoms upon glucose administration [1]. Unlike many other pNETs, approximately 90% of insulinomas are benign, solitary, and small (<2 cm). **Why other options are incorrect:** * **Gastrinoma:** This is the second most common functioning pNET. It causes **Zollinger-Ellison Syndrome**, characterized by refractory peptic ulcers and diarrhea. While common, its incidence is lower than that of insulinoma. * **Glucagonoma:** A rare tumor of alpha cells [3]. It presents with the "4 Ds": Diabetes, Dermatitis (**Necrolytic Migratory Erythema**), Deep vein thrombosis, and Depression. * **Vipoma:** Also known as Verner-Morrison syndrome or **WDHA syndrome** (Watery Diarrhea, Hypokalemia, Achlorhydria). It is significantly rarer than insulinoma. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of 90s for Insulinoma:** 90% are benign, 90% are solitary, 90% are intrapancreatic, and 90% are <2 cm. * **Localization:** Most insulinomas are distributed equally across the head, body, and tail of the pancreas. * **MEN1 Association:** While most insulinomas are sporadic, they can be associated with Multiple Endocrine Neoplasia Type 1 (3Ps: Parathyroid, Pancreas, Pituitary). * **Diagnosis:** The gold standard is the **72-hour supervised fast** showing elevated insulin and C-peptide levels during hypoglycemia [1].

Q: Which is NOT a clinical feature of Addison's disease?

Hypopigmentation. **Explanation** Addison’s disease (Primary Adrenocortical Insufficiency) is characterized by the destruction of the adrenal cortex, leading to a deficiency of cortisol, aldosterone, and adrenal androgens [1]. **Why Hypopigmentation is the Correct Answer:** In primary adrenal insufficiency, low cortisol levels trigger a compensatory increase in **ACTH** (Adrenotropic Hormone) secretion from the pituitary. ACTH is derived from a precursor molecule called **POMC** (Proopiomelanocortin). POMC also produces **MSH** (Melanocyte-Stimulating Hormone). High levels of ACTH/MSH stimulate melanocytes, leading to **hyperpigmentation** (especially in skin creases, scars, and buccal mucosa), not hypopigmentation. **Analysis of Incorrect Options:** * **Hypoglycemia:** Cortisol is a counter-regulatory hormone that promotes gluconeogenesis. Its absence leads to impaired glucose production and increased insulin sensitivity. * **Hyponatremia:** Aldosterone deficiency leads to renal wasting of sodium [2]. Additionally, cortisol deficiency increases ADH secretion (dilutional hyponatremia). * **Hyperkalemia:** Aldosterone normally promotes potassium excretion in the distal tubule. Its absence results in potassium retention and metabolic acidosis [2]. **NEET-PG High-Yield Pearls:** * **Most common cause:** Autoimmune adrenalitis (Western world); Tuberculosis (Developing countries/India) [1], [2]. * **Cosyntropin Stimulation Test:** The gold standard for diagnosis (failure of cortisol to rise >18 µg/dL) [2]. * **Secondary Adrenal Insufficiency:** Caused by pituitary failure. Key difference: **No hyperpigmentation** (low ACTH) and **no hyperkalemia** (mineralocorticoid production is preserved via the RAAS system). * **Classic Triad:** Hyponatremia, Hyperkalemia, and Azotemia.

Q: What is the most common cause of primary hyperparathyroidism?

Solitary adenoma. **Explanation:** Primary hyperparathyroidism (PHPT) is characterized by the autonomous overproduction of parathyroid hormone (PTH), leading to hypercalcemia. **1. Why Solitary Adenoma is Correct:** A **solitary parathyroid adenoma** is the most common cause, accounting for approximately **85–90%** of all cases of PHPT. It typically involves a single enlarged gland (usually the inferior parathyroid) while the remaining glands remain suppressed due to high serum calcium levels. **2. Why the Other Options are Incorrect:** * **Hyperplasia (Option A):** This involves the enlargement of all four parathyroid glands and accounts for about **10–15%** of cases. It is frequently associated with hereditary syndromes like MEN 1 and MEN 2A. * **Multiple Adenomas (Option D):** These occur in approximately **4–5%** of cases. Distinguishing multiple adenomas from hyperplasia can be surgically challenging. * **Carcinoma (Option C):** Parathyroid carcinoma is extremely rare, occurring in ** 14 mg/dL) and a palpable neck mass. **Clinical Pearls for NEET-PG:** * **Most common symptom:** Most patients are currently **asymptomatic** (detected on routine biochemical screening). * **Classic presentation:** "Bones, stones, abdominal groans, and psychic moans" (Osteitis fibrosa cystica, nephrolithiasis, peptic ulcers/pancreatitis, and depression). * **Localization:** Sestamibi (Technetium-99m) scan is the gold standard for preoperative localization of an adenoma. * **Definitive Treatment:** Surgical excision (Parathyroidectomy). A drop in intraoperative PTH by >50% (Miami criteria) indicates successful removal.

Question 1

A 22-year-old student is scheduled to undergo parathyroidectomy for hyperparathyroidism associated with familial multiglandular syndrome. His sister developed peptic ulcer disease secondary to a Zollinger-Ellison tumor of the pancreas. On examination, a swelling was noted over the posterior aspect of the patient's fifth rib. What is the most likely finding?

Accepted Answer

Osteitis fibrosa cystica (brown tumor) and subperiosteal resorption of the phalanges

Answer

Metastasis from a parathyroid carcinoma

Answer

Dermoid cyst

Answer

Eosinophilic granuloma

Question 2

A 50-year-old patient presents with a history of jaw expansion and enlargement of the maxilla. What is the most likely diagnosis?

Accepted Answer

Paget's disease

Answer

Acromegaly

Answer

Fibrous dysplasia

Answer

Hyperparathyroidism

Question 3

In a patient, there are elevated plasma cortisol levels. Dexamethasone fails to suppress cortisol secretion. What is the next step in management?

Accepted Answer

Serum ACTH

Answer

24-hour urinary metanephrines

Answer

24-hour urinary VMA

Answer

Serum DHEAS

Question 4

Which of the following is NOT a feature of primary thyrotoxicosis?

Accepted Answer

Intolerance to cold

Answer

Tremors

Answer

Warm extremities

Answer

Diarrhea

Question 5

A 67-year-old woman presents to the clinic for evaluation of numbness in her feet, with symptoms that started gradually and are more noticeable now. There is no weakness in her feet or difficulty walking. Her past medical history is significant for Type 2 diabetes for the past 10 years, for which she currently takes metformin and glyburide. Physical examination confirms sensory loss in the feet to touch and vibration. Which of the following is most characteristic of diabetic neuropathy?

Accepted Answer

It is usually bilateral.

Answer

Pain is not a feature.

Answer

It most commonly affects the brain.

Answer

It spares the autonomic system.

Question 6

Which of the following is the most common functioning pancreatic islet cell tumor?

Accepted Answer

Insulinoma

Answer

Gastrinoma

Answer

Glucagonoma

Answer

Vipoma

Question 7

Which is NOT a clinical feature of Addison's disease?

Accepted Answer

Hypopigmentation

Answer

Hypoglycemia

Answer

Hyponatremia

Answer

Hyperkalemia

Question 8

Alcoholic ketoacidosis is best managed with?

Accepted Answer

Isotonic saline infusion

Answer

Thiamine with 10% dextrose infusion

Answer

Sodium bicarbonate infusion

Answer

Fomepizole infusion

Question 9

In which of the following conditions radioactive iodine can be used in Graves' disease?

Accepted Answer

Age less than 40 years

Answer

Recurrence

Answer

Elderly

Answer

Pregnant

Question 10

What is the most common cause of primary hyperparathyroidism?

Accepted Answer

Solitary adenoma

Answer

Hyperplasia

Answer

Carcinoma

Answer

Multiple adenomas

Endocrinology — MCQs

Endocrinology — MCQs

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