Endocrinology Practice Questions

Q: What is the most common neuropathy in Diabetes Mellitus?

Distal symmetric neuropathy. **Explanation:** **Distal Symmetric Polyneuropathy (DSPN)** is the most common form of diabetic neuropathy, affecting approximately 50% of all patients with diabetes during their lifetime. It typically presents in a "stocking-and-glove" distribution because the longest nerve fibers are the most vulnerable to metabolic and microvascular injury [1]. The underlying pathophysiology involves chronic hyperglycemia leading to polyol pathway activation, oxidative stress, and advanced glycation end-products (AGEs), which cause progressive axonal degeneration [1]. **Analysis of Incorrect Options:** * **Autonomic Neuropathy:** While common and clinically significant (causing resting tachycardia, gastroparesis, or orthostatic hypotension), it usually occurs alongside or after the development of DSPN [1]. * **Mononeuropathy:** This involves isolated damage to a single nerve (e.g., Cranial Nerve III or Median nerve). While diabetes is a leading cause of mononeuropathies, they are far less frequent than the symmetric variety. * **Amyotrophy (Diabetic Lumbosacral Radiculoplexus Neuropathy):** This is a rare manifestation characterized by severe pain followed by muscle weakness and atrophy, usually in the proximal thigh muscles. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest Sign:** Loss of vibration sense (tested with a 128 Hz tuning fork) and loss of ankle reflex are often the earliest clinical findings [1]. * **Screening:** The **10g Semmes-Weinstein monofilament test** is the gold standard for identifying a "foot at risk" for ulceration [1]. * **Cranial Nerve Involvement:** CN III is the most common cranial nerve affected; it typically presents with **pupillary sparing** (due to the peripheral location of parasympathetic fibers). * **First-line Treatment:** Pregabalin, Duloxetine, or Gabapentin are preferred for symptomatic pain management.

Q: Which of the following findings is indicative of diabetes mellitus?

Random blood sugar of 205 mg/dL with polyuria. The diagnosis of Diabetes Mellitus (DM) is based on specific glycemic thresholds established by the ADA and WHO [1]. **Explanation of the Correct Option:** **Option B** is correct because a **Random Blood Sugar (RBS) ≥ 200 mg/dL** in the presence of **classic symptoms** of hyperglycemia (polyuria, polydipsia, or unexplained weight loss) is a definitive diagnostic criterion for DM [1]. A single random value without symptoms is generally insufficient and requires a repeat test. **Analysis of Incorrect Options:** * **Option A:** An **HbA1C ≥ 6.5%** is indeed diagnostic. However, in the context of standardized exams, if two options are technically correct, the one including clinical symptoms (Option B) is often prioritized as the "most" indicative clinical presentation. *Note: In some versions of this question, Option A might be considered correct, but Option B is the classic clinical definition.* * **Option C:** Impaired Fasting Glucose (IFG) is defined as a fasting plasma glucose (FPG) of 100–125 mg/dL. A value of **≥ 126 mg/dL** after an **8-hour fast** is required for a DM diagnosis [1]. 6 hours is insufficient for a true "fasting" state. * **Option D:** The 2-hour post-prandial (2-hr PP) or Oral Glucose Tolerance Test (OGTT) threshold for DM is **≥ 200 mg/dL**. Furthermore, this test must be performed using a **75g anhydrous glucose load**, not a protein-heavy meal like red meat, which does not standardize the glycemic response. **High-Yield NEET-PG Pearls:** * **Diagnostic Criteria for DM:** 1. FPG ≥ 126 mg/dL (8-hr fast) [1]. 2. 2-hr OGTT ≥ 200 mg/dL. 3. HbA1C ≥ 6.5%. 4. RBS ≥ 200 mg/dL + Symptoms [1]. * **Prediabetes:** HbA1C 5.7–6.4%; FPG 100–125 mg/dL; 2-hr OGTT 140–199 mg/dL [1]. * **Gold Standard for Gestational DM:** OGTT (Carpenter-Coustan criteria or DIPSI).

Q: Which of the following conditions might cause endocrine shock?

All of the above. **Explanation:** Endocrine shock refers to circulatory collapse caused by severe hormonal imbalances. The correct answer is **All of the above** because critical dysfunction in the thyroid or adrenal glands can lead to profound hemodynamic instability. 1. **Adrenal Insufficiency (Addisonian Crisis):** This is the most common cause of endocrine shock. A deficiency in cortisol and aldosterone leads to severe peripheral vasodilation, decreased cardiac contractility, and hypovolemia (due to sodium and water loss) [1]. This results in distributive and hypovolemic shock that is often refractory to vasopressors until corticosteroids are administered. 2. **Hypothyroidism (Myxedema Coma):** Severe hypothyroidism causes shock through multiple mechanisms: bradycardia, decreased myocardial contractility (reduced cardiac output), and increased systemic vascular resistance [1]. It can also lead to pericardial effusion and associated adrenal insufficiency [1]. 3. **Hyperthyroidism (Thyroid Storm):** While hyperthyroidism typically causes a high-output state, a "Thyroid Storm" can lead to high-output heart failure, tachyarrhythmias, and profound dehydration, eventually resulting in cardiovascular collapse and shock [1]. **Clinical Pearls for NEET-PG:** * **Waterhouse-Friderichsen Syndrome:** Adrenal shock caused by hemorrhagic necrosis of the adrenal glands, typically secondary to *Neisseria meningitidis* sepsis. * **Refractory Shock:** Always suspect adrenal insufficiency in a patient with shock that does not respond to fluids or inotropes [1]. * **Treatment Priority:** In suspected adrenal crisis, do not wait for laboratory confirmation; administer IV Hydrocortisone (100mg stat) immediately. * **Myxedema Coma Triad:** Hypothermia, Bradycardia, and Altered Mental Status.

Q: Which of the following is NOT a feature of hypocalcemia?

Depressed tendon reflexes. The correct answer is **C. Depressed tendon reflexes**. **1. Underlying Medical Concept:** Hypocalcemia increases neuromuscular excitability. Calcium ions normally stabilize the neuronal membrane by blocking sodium channels. When extracellular calcium levels are low, the threshold for depolarization decreases, making neurons **hyperexcitable**. This leads to spontaneous firing of motor and sensory nerves. Consequently, hypocalcemia is characterized by **hyperreflexia** (brisk tendon reflexes), tetany, and muscle spasms. Depressed or absent reflexes are typically seen in **hypercalcemia** or hypermagnesemia, where the membrane is over-stabilized. **2. Analysis of Incorrect Options:** * **A & B (Numbness, tingling, and circumoral paresthesia):** These are the earliest sensory manifestations of hypocalcemia. The hyperexcitability of sensory nerve fibers manifests as "pins and needles" sensations, particularly around the mouth (circumoral) and in the fingertips. * **D (Skin irritability and sensitivity):** Chronic hypocalcemia affects ectodermal tissues, leading to dry, scaly skin, brittle nails, and dermatological sensitivity. Neuromuscular irritability also manifests as "irritability" in the clinical sense (agitation or seizures). **3. High-Yield Clinical Pearls for NEET-PG:** * **Chvostek’s Sign:** Tapping the facial nerve leads to twitching of facial muscles. * **Trousseau’s Sign:** Carpopedal spasm induced by inflating a BP cuff above systolic pressure for 3 minutes (more specific than Chvostek’s). * **ECG Finding:** The classic hallmark is **prolonged QT interval** (due to lengthening of the ST segment) [1]. * **Etiology:** Most common cause is post-thyroidectomy (accidental parathyroid removal) [1] or Vitamin D deficiency [1].

Q: What is the effect of calcitonin on bone resorption?

Inhibits resorption. Calcitonin is a 32-amino acid peptide hormone secreted by the **parafollicular cells (C-cells) of the thyroid gland**. Its primary physiological role is to lower plasma calcium levels, acting as a functional antagonist to Parathyroid Hormone (PTH). [1] **Why Option A is correct:** Calcitonin directly **inhibits bone resorption** by acting on specific receptors located on **osteoclasts**. [1] Upon binding, it causes the osteoclasts to lose their "ruffled borders" and shrink, effectively decreasing their resorptive activity. This leads to a reduction in the release of calcium and phosphate from the bone matrix into the blood. [1] **Why the other options are incorrect:** * **Option B:** Promoting resorption is the primary function of **PTH** and **Vitamin D** (in high doses), which increase blood calcium. * **Option C:** Calcitonin has a unidirectional effect on bone; it is purely anti-resorptive and does not stimulate resorption under any physiological condition. * **Option D:** While calcitonin prevents the breakdown of bone, it does not directly "enhance" the complex process of mineralization (which requires adequate calcium, phosphate, and alkaline phosphatase activity). Its effect is passive preservation rather than active formation. **High-Yield Clinical Pearls for NEET-PG:** * **Marker:** Serum calcitonin is a sensitive tumor marker for **Medullary Thyroid Carcinoma (MTC)**. * **Therapeutic Use:** Exogenous calcitonin (often Salmon calcitonin due to higher potency) is used in the acute management of **Hypercalcemic crisis**, **Paget’s disease of bone**, and to provide analgesic effects in **osteoporotic vertebral fractures**. * **Escape Phenomenon:** The hypocalcemic effect of calcitonin is short-lived because osteoclasts eventually "downregulate" their receptors, a process known as tachyphylaxis or the "escape phenomenon." [1]

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

Increased renin level. ### Explanation **Primary Hyperaldosteronism (Conn’s Syndrome)** is characterized by the autonomous overproduction of aldosterone from the adrenal cortex (most commonly due to an adrenal adenoma or bilateral adrenal hyperplasia). **Why "Increased renin level" is the correct answer:** In primary hyperaldosteronism, the excess aldosterone leads to sodium and water retention, which increases effective circulating volume and blood pressure. This physiological state triggers a **negative feedback mechanism** on the juxtaglomerular apparatus, resulting in the **suppression of renin**. Therefore, a **low plasma renin level** is a hallmark of the disease. An increased renin level would instead point toward *secondary* hyperaldosteronism (e.g., renal artery stenosis). **Analysis of Incorrect Options:** * **A. Hypokalemia:** Aldosterone acts on the principal cells of the collecting duct to secrete potassium into the urine. Chronic excess leads to significant depletion of serum potassium. * **B. Hypertension:** Increased sodium reabsorption in the distal nephron leads to volume expansion, making hypertension a cardinal clinical feature. * **C. Hypernatremia:** While sodium is retained, it is often "mild" due to the **Aldosterone Escape Phenomenon** (where ANP release prevents massive edema); however, serum sodium levels typically remain at the high end of normal or slightly elevated. **NEET-PG High-Yield Pearls:** * **Screening Test of Choice:** Plasma Aldosterone Concentration (PAC) to Plasma Renin Activity (PRA) ratio. A **PAC:PRA ratio > 20-30** is highly suggestive. * **Confirmatory Test:** Saline infusion test (failure to suppress aldosterone) or Oral Salt Loading test. * **Metabolic State:** Patients typically exhibit **Metabolic Alkalosis** (due to H+ secretion in the intercalated cells). * **Clinical Clue:** Suspect this in a young patient with resistant hypertension and unexplained hypokalemia.

Q: An 83-year-old man with poor nutrition presents with easy bruising and bleeding gums. On examination, he has inflamed bleeding gums, multiple areas of ecchymoses, and perifollicular hemorrhages. His coagulation profile and liver function tests are normal. What is the most likely diagnosis for this patient's vitamin deficiency or excess?

vitamin C. The clinical presentation of **perifollicular hemorrhages**, **bleeding gums**, and **easy bruising** in an elderly patient with poor nutrition is pathognomonic for **Scurvy (Vitamin C deficiency)** [1]. **1. Why Vitamin C is correct:** Vitamin C (ascorbic acid) is a vital cofactor for the enzymes **prolyl and lysyl hydroxylase**, which are responsible for the hydroxylation of proline and lysine residues during **collagen synthesis** [4]. This process is essential for the cross-linking of collagen fibers. Deficiency leads to defective collagen formation, resulting in weakened capillary walls and connective tissue [1]. This manifests as: * **Hemorrhagic signs:** Perifollicular hemorrhages (corkscrew hairs), ecchymoses, and petechiae. * **Oral signs:** Swollen, friable, and bleeding gums (gingivitis) [1]. * **Impaired wound healing:** Due to the inability to form stable collagen [1]. **2. Why other options are incorrect:** * **Niacin (B3):** Deficiency causes **Pellagra**, characterized by the "3 Ds": Dermatitis (photosensitive Casal’s necklace [3]), Diarrhea, and Dementia. It does not typically cause bleeding manifestations. * **Thiamine (B1):** Deficiency leads to **Beriberi** (Dry: peripheral neuropathy; Wet: high-output heart failure) or **Wernicke-Korsakoff syndrome** [2]. * **Pyridoxine (B6):** Deficiency causes sideroblastic anemia, peripheral neuropathy, and seborrheic dermatitis, but not perifollicular hemorrhages. **3. NEET-PG High-Yield Pearls:** * **Classic Triad of Scurvy:** Anemia, Myalgia, and Dermatological signs (perifollicular hemorrhage). * **Bone findings (Pediatric Scurvy/Barlow’s Disease):** Subperiosteal hemorrhage, "Trümmerfeld zone" (fragmented bone), and "Wimberger ring sign" on X-ray. * **Lab Clue:** Coagulation studies (PT/aPTT) and platelet counts are **normal** in Scurvy; the bleeding is due to structural vessel wall weakness, not a clotting defect.

Q: A 60-year-old woman presents with concerns about osteoporosis due to her mother's recent hip fracture. She has a 50-pack-year smoking history, started hormone replacement therapy for 6 years after menopause at age 49, and has a BMI of 26.7 kg/m². She takes a multivitamin and levothyroxine 50 mg/d. Her exercise includes lawn mowing and gardening. What is the most appropriate recommendation for osteoporosis screening for this patient?

Dual-x-ray absorptiometry (DXA) scan. **Explanation:** The gold standard for screening and diagnosing osteoporosis is **Dual-energy X-ray Absorptiometry (DXA)**. According to international guidelines (USPSTF and ISCD), screening is recommended for all women aged **≥65 years** and younger postmenopausal women (like this 60-year-old patient) who have an increased risk of fractures [1]. This patient has multiple risk factors: a positive family history (maternal hip fracture) and a significant smoking history [2]. * **Why DXA is the Correct Choice:** DXA measures Bone Mineral Density (BMD) at the hip and lumbar spine. It is the preferred method because of its high precision, short scan time, low radiation exposure, and its ability to predict fracture risk and monitor response to therapy [2]. **Analysis of Incorrect Options:** * **A. Nuclear medicine bone scan:** This uses technetium-99m to detect increased bone turnover (e.g., metastases, osteomyelitis, or occult fractures). It cannot measure bone density or diagnose osteoporosis. * **C. Quantitative CT (QCT):** While it provides a 3D measurement of bone density, it involves significantly higher radiation doses and is more expensive than DXA. It is not used for routine screening. * **D. Peripheral bone densitometry:** This measures density at the wrist or heel. While useful for mass screening in resource-limited settings, it is less predictive of hip fracture risk and cannot be used for monitoring treatment. **NEET-PG Clinical Pearls:** * **T-score:** Compares patient BMD to a young-adult reference population. * Normal: ≥ -1.0 * – Osteopenia: -1.0 to -2.5 * **Osteoporosis: ≤ -2.5** * **Z-score:** Compares patient BMD to an age-matched population (used for premenopausal women and men <50). * **FRAX Tool:** Used to calculate the 10-year probability of a major osteoporotic fracture [2].

Question 1

What is the most common neuropathy in Diabetes Mellitus?

Accepted Answer

Distal symmetric neuropathy

Answer

Autonomic neuropathy

Answer

Mononeuropathy

Answer

Amyotrophy

Question 2

Which of the following findings is indicative of diabetes mellitus?

Accepted Answer

Random blood sugar of 205 mg/dL with polyuria

Answer

HbA1C of 6.5%

Answer

Blood sugar of 140 mg/dL after 6 hours of fasting

Answer

Glucose of 190 mg/dL after 2 hours of eating red meat

Question 3

A 16-year-old girl presents with a one-month history of visual disturbances, including difficulty seeing people unless they are directly in front of her and walking into doors. Her menstrual cycles have become irregular and have ceased in the past few months. Physical examination reveals bilateral temporal visual field deficits with normal nasal visual fields. A mass is identified inferior to the hypothalamus on cranial imaging. Which hormone do the cells within this mass most likely produce?

Accepted Answer

Thyroid-stimulating hormone

Answer

Oxytocin

Answer

Somatostatin

Answer

Thyrotropin-releasing hormone

Question 4

Which of the following conditions might cause endocrine shock?

Accepted Answer

All of the above

Answer

Hypothyroidism

Answer

Hyperthyroidism

Answer

Adrenal insufficiency

Question 5

Which of the following is NOT a feature of hypocalcemia?

Accepted Answer

Depressed tendon reflexes

Answer

Numbness and tingling

Answer

Circumoral paresthesia

Answer

Skin irritability and sensitivity

Question 6

What is the most common differential diagnosis of hyperthyroidism in a young female?

Accepted Answer

Anxiety neurosis

Answer

Hysteria

Answer

Essential tremor

Answer

Parkinsonism

Question 7

What is the effect of calcitonin on bone resorption?

Accepted Answer

Inhibits resorption

Answer

Promotes resorption

Answer

Has both properties

Answer

Enhances mineralization

Question 8

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

Accepted Answer

Increased renin level

Answer

Hypokalemia

Answer

Hypertension

Answer

Hypernatremia

Question 9

An 83-year-old man with poor nutrition presents with easy bruising and bleeding gums. On examination, he has inflamed bleeding gums, multiple areas of ecchymoses, and perifollicular hemorrhages. His coagulation profile and liver function tests are normal. What is the most likely diagnosis for this patient's vitamin deficiency or excess?

Accepted Answer

vitamin C

Answer

niacin

Answer

thiamine

Answer

pyridoxine

Question 10

A 60-year-old woman presents with concerns about osteoporosis due to her mother's recent hip fracture. She has a 50-pack-year smoking history, started hormone replacement therapy for 6 years after menopause at age 49, and has a BMI of 26.7 kg/m². She takes a multivitamin and levothyroxine 50 mg/d. Her exercise includes lawn mowing and gardening. What is the most appropriate recommendation for osteoporosis screening for this patient?

Accepted Answer

Dual-x-ray absorptiometry (DXA) scan

Answer

Nuclear medicine bone scan

Answer

Quantitative CT bone densitometry

Answer

Peripheral bone densitometry

Endocrinology — MCQs

Endocrinology — MCQs

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