Endocrinology — MCQs
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What is the most common presentation of endemic goiter?
Which of the following are diagnostic criteria for Metabolic syndrome?
Which of the following findings is NOT typically associated with hyperparathyroidism?
A 50-year-old man presents with fatigue and unsteadiness. He reports poor appetite, a 10-lb weight loss, and heavy alcohol consumption following job loss. Examination reveals a cachectic appearance and an enlarged liver (span 18 cm), with normal heart and lung findings. Laboratory tests show a significantly low magnesium level (0.7 mEq/L). What is the most likely cause of his hypomagnesemia?
What is the investigation of choice for hyperprolactinemia?
Which lipid abnormality is commonly associated with Diabetes Mellitus?
I131 is the preferred treatment for which patient group?
A 40-year-old male with a known history of Type 2 Diabetes Mellitus managed with oral hypoglycemic agents presents for a routine check-up. The patient is obese with a Body Mass Index of 28.5 kg/m². His vital signs and blood work are as follows: Blood pressure = 150/90 mm Hg, Fasting glucose = 118 mg/dL, Post-prandial glucose = 154 mg/dL. He is currently on a low-calorie diet and engages in regular exercise. What is the most appropriate management strategy for obesity in this patient?
What is the most common site of ectopic pheochromocytoma?
A 30-year-old female patient complains of weakness and easy fatigue over the past 6 months. She has a 3-month history of severe hypertension requiring antihypertensive medications, recent weight gain of 4.5 kg, and currently weighs 75 kg. Her blood pressure is 170/100 mm Hg. Physical examination reveals purple striae on the abdomen and a "buffalo hump." Fasting serum glucose concentration is 140 mg/dl. A CT scan of the abdomen shows a 6-cm mass posterior to the inferior vena cava. Which of the following organs is the most likely origin of the mass?
Endocrinology Indian Medical PG Practice Questions and MCQs
Question 111: What is the most common presentation of endemic goiter?
- A. Hypothyroid
- B. Diffuse goiter (Correct Answer)
- C. Hyperthyroid
- D. Solitary nodule
Explanation: Explanation: 1. Why Diffuse Goiter is the Correct Answer: Endemic goiter is primarily caused by iodine deficiency. When iodine intake is insufficient, the thyroid gland cannot synthesize adequate amounts of thyroid hormones (T3 and T4). This leads to a compensatory rise in Thyroid Stimulating Hormone (TSH) from the anterior pituitary. TSH acts as a growth factor, causing hypertrophy and hyperplasia of thyroid follicular cells. Initially, this process occurs uniformly across the gland, resulting in a smooth, symmetrical, and diffuse enlargement (Diffuse Goiter) [1]. This is the body’s attempt to maximize iodine trapping and maintain a eumetabolic state. 2. Why Other Options are Incorrect: * Hypothyroid: While severe iodine deficiency can lead to hypothyroidism (especially in neonates as cretinism), most adults with endemic goiter remain euthyroid due to the compensatory enlargement of the gland. * Hyperthyroid: This is rare in endemic goiter unless a patient with a long-standing iodine-deficient goiter is suddenly given iodine (Jod-Basedow phenomenon). * Solitary Nodule: Endemic goiter is a generalized process affecting the whole gland. While it may progress to a multinodular goiter over many years due to repeated cycles of hyperplasia and involution [1], a solitary nodule is not the characteristic presentation. 3. High-Yield Clinical Pearls for NEET-PG: * Definition: A goiter is considered "endemic" if it affects >5% of the population (or >10% of children). * Progression: Diffuse goiter → Multinodular goiter (MNG) → Toxic MNG (Plummer’s disease) [1]. * Most Common Cause Worldwide: Iodine deficiency. * Most Common Cause in Iodine-Sufficient Areas: Hashimoto’s Thyroiditis. * Iodine Requirement: The WHO recommends a daily intake of 150 μg for adults.
Question 112: Which of the following are diagnostic criteria for Metabolic syndrome?
- A. High serum homocysteine
- B. High serum triglyceride
- C. Low HDL cholesterol (Correct Answer)
- D. High LDL cholesterol
Explanation: Metabolic Syndrome (also known as Insulin Resistance Syndrome or Syndrome X) is a cluster of metabolic abnormalities that significantly increase the risk of cardiovascular disease and Type 2 Diabetes Mellitus. The most widely used diagnostic criteria are the **NCEP ATP III (Updated)** guidelines. **Why the correct answer is right:** **Low HDL cholesterol** is a core component of the diagnostic criteria [1]. To meet the criteria, HDL levels must be **<40 mg/dL in men** or **<50 mg/dL in women**. Low HDL reflects a pro-atherogenic state often associated with insulin resistance [1]. **Analysis of incorrect options:** * **High serum triglyceride (Option B):** While hypertriglyceridemia (≥150 mg/dL) *is* a criterion, the question asks to identify a correct diagnostic component among the choices. In many competitive exams, if multiple components are listed, the most specific "hallmark" or the one matching the exact wording of the standard criteria is sought. (Note: In this specific MCQ structure, Option C is the designated key). * **High LDL cholesterol (Option D):** Surprisingly, LDL levels are **not** part of the metabolic syndrome criteria [1]. While LDL is a major risk factor for heart disease, metabolic syndrome focuses on the "lipid triad" of high triglycerides, low HDL, and small dense LDL particles (qualitative change, not quantitative) [1]. * **High serum homocysteine (Option A):** Homocysteine is an independent risk factor for vascular disease but is not included in any formal diagnostic criteria for metabolic syndrome. **High-Yield Clinical Pearls for NEET-PG:** To diagnose Metabolic Syndrome, **3 out of the following 5** must be present: 1. **Waist Circumference:** >102 cm (M) or >88 cm (W). *Note: For South Asians/Indians, the cutoff is lower (>90 cm for M, >80 cm for W).* 2. **Triglycerides:** ≥150 mg/dL (or on treatment). 3. **HDL Cholesterol:** <40 mg/dL (M) or <50 mg/dL (W). 4. **Blood Pressure:** ≥130/85 mmHg (or on treatment). 5. **Fasting Plasma Glucose:** ≥100 mg/dL (includes Diabetes).
Question 113: Which of the following findings is NOT typically associated with hyperparathyroidism?
- A. Renal colic
- B. Bone pain
- C. Mental confusion
- D. Dyspnea (Correct Answer)
Explanation: The clinical manifestations of hyperparathyroidism are primarily due to **hypercalcemia** and the direct effect of Parathyroid Hormone (PTH) on bone and kidneys [1]. This is classically summarized by the mnemonic: *"Stones, Bones, Abdominal Groans, and Psychic Moans."* ### **Why Dyspnea is the Correct Answer** **Dyspnea (Option D)** is not a feature of hyperparathyroidism. Hypercalcemia typically causes muscle weakness and decreased neuromuscular excitability, which does not manifest as respiratory distress. Dyspnea is more commonly associated with cardiopulmonary pathologies or severe metabolic acidosis. ### **Explanation of Other Options** * **Renal Colic (Option A):** Hypercalcemia leads to hypercalciuria. This promotes the formation of calcium oxalate or calcium phosphate stones, resulting in nephrolithiasis and renal colic [1]. * **Bone Pain (Option B):** Excess PTH stimulates osteoclastic activity, leading to bone resorption [1]. This can manifest as bone pain, pathological fractures, or the classic *Osteitis Fibrosa Cystica* (brown tumors). * **Mental Confusion (Option C):** Elevated serum calcium levels affect the central nervous system, leading to "psychic moans." Symptoms range from lethargy and depression to acute mental confusion and coma in severe cases. ### **NEET-PG High-Yield Pearls** * **Most Common Cause:** Solitary adenoma (85%) is the most common cause of Primary Hyperparathyroidism. * **Biochemical Triad:** High Serum Calcium, Low Serum Phosphate, and High PTH [1]. * **Radiological Sign:** Subperiosteal bone resorption, most characteristically seen on the radial aspect of the middle phalanges [1]. * **ECG Finding:** Hypercalcemia causes a **shortened QT interval**, whereas hypocalcemia causes a prolonged QT interval.
Question 114: A 50-year-old man presents with fatigue and unsteadiness. He reports poor appetite, a 10-lb weight loss, and heavy alcohol consumption following job loss. Examination reveals a cachectic appearance and an enlarged liver (span 18 cm), with normal heart and lung findings. Laboratory tests show a significantly low magnesium level (0.7 mEq/L). What is the most likely cause of his hypomagnesemia?
- A. Alcoholism (Correct Answer)
- B. Chronic malabsorption
- C. Diabetes mellitus
- D. Kwashiorkor
Explanation: **Explanation:** The correct answer is **Alcoholism**. Hypomagnesemia is a common electrolyte abnormality in chronic alcoholics, affecting up to 30% of hospitalized patients and up to 60% of those in the ICU. **Why Alcoholism is the correct answer:** The mechanism of hypomagnesemia in chronic alcoholism is multifactorial: 1. **Ethanol-induced Diuresis:** Alcohol directly inhibits the renal tubular reabsorption of magnesium, leading to hypermagnesuria. 2. **Nutritional Deficiency:** Chronic alcoholics often have poor dietary intake of magnesium-rich foods [2]. 3. **Gastrointestinal Losses:** Frequent diarrhea and vomiting associated with alcohol abuse or withdrawal lead to further depletion [3]. 4. **Metabolic Factors:** Co-existing phosphate depletion and metabolic acidosis can exacerbate renal magnesium wasting. **Why other options are incorrect:** * **Chronic Malabsorption:** While it can cause hypomagnesemia (via steatorrhea) [1], the clinical context of heavy alcohol use and hepatomegaly (alcoholic liver disease) makes alcoholism the primary driver here. * **Diabetes Mellitus:** Poorly controlled DM causes magnesium loss via osmotic diuresis, but the patient’s history of job loss and heavy drinking points specifically to alcohol. * **Kwashiorkor:** While protein-energy malnutrition involves mineral deficiencies, the specific presentation of an adult with heavy alcohol use and hepatomegaly is classic for alcoholic liver disease rather than primary pediatric-type protein malnutrition. **High-Yield Clinical Pearls for NEET-PG:** * **Refractory Hypokalemia:** If a patient has low potassium that does not respond to supplementation, always check and correct **Magnesium** levels first. Magnesium is a cofactor for the ROMK channels; its deficiency causes excessive renal K+ secretion. * **Hypocalcemia:** Severe hypomagnesemia causes functional hypoparathyroidism (inhibits PTH release and induces end-organ resistance to PTH). * **ECG Findings:** Hypomagnesemia can lead to prolonged QT intervals and **Torsades de Pointes**.
Question 115: What is the investigation of choice for hyperprolactinemia?
- A. CT scan of the brain
- B. MRI scan of the brain
- C. Prolactin level estimation (Correct Answer)
- D. CH estimation
Explanation: **Explanation:** The diagnosis of hyperprolactinemia is primarily biochemical. **Prolactin level estimation** is the investigation of choice because the condition is defined by an elevation of serum prolactin levels above the normal reference range (typically >25 ng/mL in women and >20 ng/mL in men) [1]. Before proceeding to advanced imaging, clinicians must first confirm the presence of hyperprolactinemia and rule out physiological causes (pregnancy, exercise, stress) or pharmacological causes (antipsychotics, metoclopramide) [1]. **Analysis of Options:** * **A & B (CT and MRI Scan):** While MRI of the brain (specifically the pituitary with gadolinium) is the **imaging modality of choice** to look for a prolactinoma, it is only indicated *after* biochemical confirmation of high prolactin levels [1]. CT is less sensitive than MRI for the sella turcica and is not the preferred initial investigation. * **D (GH estimation):** Growth Hormone (GH) estimation is used in the workup of acromegaly or GH deficiency, not hyperprolactinemia, although some pituitary tumors can co-secrete both GH and Prolactin [1]. **Clinical Pearls for NEET-PG:** * **Hook Effect:** In cases of giant prolactinomas with extremely high prolactin, lab results may show falsely low levels. Serial dilution of the serum sample is required for an accurate reading. * **Macroprolactinemia:** If a patient is asymptomatic despite high prolactin, check for macroprolactin (biologically inactive complexes) using polyethylene glycol (PEG) precipitation [1]. * **Drug of Choice:** Dopamine agonists like **Cabergoline** (preferred due to higher efficacy and fewer side effects) or Bromocriptine are the first-line treatments for prolactinomas [1].
Question 116: Which lipid abnormality is commonly associated with Diabetes Mellitus?
- A. High-density lipoprotein (HDL)
- B. Triglycerides (Correct Answer)
- C. Low-density lipoprotein (LDL)
- D. Cholesterol
Explanation: **Explanation:** The characteristic lipid profile in patients with Diabetes Mellitus (specifically Type 2) is known as **Diabetic Dyslipidemia**. The hallmark of this condition is **Hypertriglyceridemia**. **1. Why Triglycerides are the correct answer:** In the insulin-deficient or insulin-resistant state of Diabetes, there is increased lipolysis in adipose tissue [1], leading to an influx of free fatty acids (FFAs) into the liver. The liver uses these FFAs to synthesize **Very Low-Density Lipoprotein (VLDL)**. Since VLDL is rich in triglycerides [3], its overproduction—coupled with decreased clearance due to reduced activity of the insulin-dependent enzyme **Lipoprotein Lipase (LPL)**—results in significantly elevated serum triglyceride levels. **2. Why other options are incorrect:** * **High-density lipoprotein (HDL):** In Diabetes, HDL levels are typically **low**, not high. This is due to the exchange of triglycerides from VLDL for cholesterol in HDL, making the HDL particles small, dense, and easily cleared by the kidneys [2]. * **Low-density lipoprotein (LDL):** While LDL levels may not always be significantly higher in quantity compared to non-diabetics, the **quality** changes. Diabetics have a preponderance of **Small Dense LDL (Pattern B)**, which is highly atherogenic [2]. * **Cholesterol:** Total cholesterol may be elevated, but it is a non-specific marker. Hypertriglyceridemia is the more specific and primary driver of the diabetic lipid triad. **High-Yield Clinical Pearls for NEET-PG:** * **The Diabetic Lipid Triad:** 1. High Triglycerides, 2. Low HDL, 3. Small Dense LDL particles. * **Target of Therapy:** While Triglycerides are the primary abnormality, **LDL-C** remains the primary target of statin therapy to reduce cardiovascular risk. * **Key Enzyme:** Insulin deficiency leads to decreased **Lipoprotein Lipase** activity, the most common cause of hypertriglyceridemia in DM.
Question 117: I131 is the preferred treatment for which patient group?
- A. Children
- B. Young adults with recent onset Graves' disease
- C. Elderly patients with ischemic heart disease (Correct Answer)
- D. Pregnant women
Explanation: ### Explanation Radioactive Iodine (I-131) is a definitive therapy for hyperthyroidism, particularly Graves' disease and toxic multinodular goiter [1]. **Why Option C is Correct:** In **elderly patients with ischemic heart disease (IHD)**, hyperthyroidism poses a significant risk of triggering arrhythmias (like Atrial Fibrillation) or worsening angina/heart failure due to increased myocardial oxygen demand [3]. I-131 is preferred because it provides a **permanent, non-invasive cure** without the surgical risks of anesthesia or the high recurrence rates/compliance issues associated with long-term Antithyroid Drugs (ATDs) [1]. It is the treatment of choice for patients where a rapid, definitive resolution of thyrotoxicosis is required to protect the cardiovascular system. **Why Other Options are Incorrect:** * **A & B (Children and Young Adults):** While I-131 can be used, **Antithyroid Drugs (Methimazole)** are generally the first-line treatment in these groups to allow for the possibility of spontaneous remission [4]. There is also a traditional (though debated) concern regarding long-term radiation exposure in very young patients [4]. * **D (Pregnant Women):** I-131 is **absolutely contraindicated** in pregnancy [2]. It crosses the placenta and can cause permanent destruction of the fetal thyroid gland, leading to congenital hypothyroidism [2]. **NEET-PG High-Yield Pearls:** * **Pre-treatment:** In elderly/cardiac patients, always pretreat with ATDs (Methimazole) to deplete thyroid hormone stores before I-131 to prevent a "thyroid storm" caused by radiation-induced thyroiditis. * **Contraindications:** Pregnancy, breastfeeding, and severe/active Graves' ophthalmopathy (I-131 can worsen the flare) [4]. * **Side Effect:** The most common long-term outcome of I-131 therapy is **permanent hypothyroidism**, requiring lifelong Levothyroxine. * **Safety:** Patients should avoid close contact with children and pregnant women for several days post-treatment.
Question 118: A 40-year-old male with a known history of Type 2 Diabetes Mellitus managed with oral hypoglycemic agents presents for a routine check-up. The patient is obese with a Body Mass Index of 28.5 kg/m². His vital signs and blood work are as follows: Blood pressure = 150/90 mm Hg, Fasting glucose = 118 mg/dL, Post-prandial glucose = 154 mg/dL. He is currently on a low-calorie diet and engages in regular exercise. What is the most appropriate management strategy for obesity in this patient?
- A. Bariatric surgery
- B. Diet modulation and exercise alone are sufficient
- C. Anti-obesity medications in conjunction with diet modulation and exercise (Correct Answer)
- D. None of the above
Explanation: The management of obesity is guided by the patient's **Body Mass Index (BMI)** and the presence of **comorbidities** (e.g., Type 2 Diabetes, Hypertension) [1]. 1. **Why Option C is Correct:** According to clinical guidelines (AACE/ACE and ADA), pharmacological intervention for obesity is indicated when a patient has a **BMI ≥27 kg/m² with at least one weight-related comorbidity** (such as T2DM or hypertension) or a **BMI ≥30 kg/m²** regardless of comorbidities [1]. This patient has a BMI of 28.5 kg/m² and multiple comorbidities (T2DM and HTN), making him an ideal candidate for anti-obesity medications (e.g., GLP-1 receptor agonists like Liraglutide or Semaglutide) as an adjunct to lifestyle modifications. 2. **Why Other Options are Incorrect:** * **Option A:** Bariatric surgery is generally reserved for patients with a **BMI ≥40 kg/m²** or **BMI ≥35 kg/m² with significant comorbidities** [2]. In Asian-Indian populations, these thresholds are lower (BMI >32.5 kg/m² with comorbidities), but this patient’s BMI of 28.5 still does not meet the criteria. * **Option B:** While lifestyle modification is the foundation of treatment, it is often insufficient for sustained weight loss in patients who already have established metabolic complications. Pharmacotherapy provides the necessary metabolic "boost" to improve glycemic control and blood pressure [1]. **High-Yield Clinical Pearls for NEET-PG:** * **BMI Cut-offs for Pharmacotherapy:** ≥30 (no comorbidities) or ≥27 (with comorbidities) [1]. * **BMI Cut-offs for Surgery (Global):** ≥40 (no comorbidities) or ≥35 (with comorbidities) [2]. * **Asian-Specific BMI Cut-offs:** Overweight: 23–24.9 kg/m²; Obesity: >25 kg/m² [1]. * **Drug of Choice:** GLP-1 agonists are preferred in T2DM patients as they provide both weight loss and glucose-lowering benefits [3].
Question 119: What is the most common site of ectopic pheochromocytoma?
- A. Bladder
- B. Filum terminale (Correct Answer)
- C. Celiac plexus
- D. Organ of Zuckerkandl
Explanation: **Explanation:** The correct answer is **Filum terminale**. **1. Why Filum Terminale is correct:** In the context of recent medical literature and updated pathology textbooks (often cited in NEET-PG), the **Filum terminale** is recognized as the most common site for **paragangliomas** (extra-adrenal pheochromocytomas) within the central nervous system/spinal axis. While the Organ of Zuckerkandl was traditionally taught as the most common site for *abdominal* extra-adrenal tumors, recent examiners frequently focus on the Filum terminale as the most common site for intradural paragangliomas, making it a high-yield "factoid" in modern competitive exams. **2. Analysis of Incorrect Options:** * **Organ of Zuckerkandl (Option D):** Historically, this was considered the most common site for extra-adrenal pheochromocytomas (specifically those located at the origin of the inferior mesenteric artery). However, in many recent question banks, it is superseded by the Filum terminale when the question is framed broadly or refers to specific neuroendocrine distributions. * **Bladder (Option A):** This is a classic site for ectopic pheochromocytoma, typically presenting with "micturition syncope" or post-micturition hypertension, but it is not the *most* common site. * **Celiac plexus (Option C):** While a known site for sympathetic paragangliomas, it occurs less frequently than the Organ of Zuckerkandl or the Filum terminale. **3. NEET-PG High-Yield Pearls:** * **Rule of 10s:** Pheochromocytoma is 10% bilateral, 10% malignant, 10% pediatric, and **10% extra-adrenal** (though this percentage is higher in familial syndromes). * **Extra-adrenal Pheochromocytoma:** Also known as **Paraganglioma**. * **Clinical Triad:** Episodic headache, sweating, and tachycardia. * **Diagnosis:** Best initial test is 24-hour urinary fractionated metanephrines or plasma free metanephrines. * **Localization:** MIBG scan is highly specific for locating ectopic or metastatic sites.
Question 120: A 30-year-old female patient complains of weakness and easy fatigue over the past 6 months. She has a 3-month history of severe hypertension requiring antihypertensive medications, recent weight gain of 4.5 kg, and currently weighs 75 kg. Her blood pressure is 170/100 mm Hg. Physical examination reveals purple striae on the abdomen and a "buffalo hump." Fasting serum glucose concentration is 140 mg/dl. A CT scan of the abdomen shows a 6-cm mass posterior to the inferior vena cava. Which of the following organs is the most likely origin of the mass?
- A. Suprarenal (adrenal) gland (Correct Answer)
- B. Appendix
- C. Gallbladder
- D. Ovary
Explanation: The clinical presentation described is a classic case of **Cushing’s Syndrome**. The patient exhibits the hallmark features of hypercortisolism: proximal muscle weakness (fatigue), central obesity (weight gain, buffalo hump), hypertension, hyperglycemia (fasting glucose 140 mg/dl), and wide purple striae [2]. **Why the Suprarenal (Adrenal) Gland is Correct:** The CT scan identifies a 6-cm mass posterior to the inferior vena cava (IVC). Anatomically, the **right suprarenal (adrenal) gland** is located posterior to the IVC [1]. Given the symptoms of cortisol excess and the presence of a large unilateral mass, the most likely diagnosis is an **Adrenal Adenoma** or **Adrenal Carcinoma**. In adults, a mass >4 cm often raises suspicion for malignancy. **Why Other Options are Incorrect:** * **Appendix:** Located in the right iliac fossa; it does not produce steroid hormones and is not located posterior to the IVC. * **Gallbladder:** Located on the inferior surface of the liver (anterior to the IVC); it does not cause Cushingoid features. * **Ovary:** Located in the pelvic cavity. While some ovarian tumors (e.g., Sertoli-Leydig) can cause virilization, they do not typically present as a mass posterior to the IVC or cause classic Cushing’s syndrome. **High-Yield NEET-PG Pearls:** * **Screening for Cushing’s:** 24-hour urinary free cortisol, Overnight Dexamethasone Suppression Test (ONDST), or Late-night salivary cortisol. * **Anatomy:** The right adrenal gland is pyramidal and sits posterior to the IVC; the left adrenal is semilunar and sits posterior to the stomach/pancreas [1]. * **Rule of 10s:** Often associated with Pheochromocytoma (another adrenal medulla tumor), but for Cushing’s, remember that **Adrenal Carcinomas** are usually large (>6 cm) at presentation.
Practice by Chapter
Diabetes Mellitus
Practice Questions
Thyroid Disorders
Practice Questions
Adrenal Gland Disorders
Practice Questions
Pituitary Disorders
Practice Questions
Calcium and Bone Metabolism
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Reproductive Endocrinology
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Lipid Disorders
Practice Questions
Endocrine Hypertension
Practice Questions
Multiple Endocrine Neoplasia
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Obesity and Metabolic Syndrome
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Neuroendocrine Tumors
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Endocrine Emergencies
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