Endocrinology Practice Questions

Q: MODY 1 is caused by mutations in which of the following genes?

HNF-4 alpha. Maturity-Onset Diabetes of the Young (MODY) is a group of monogenic disorders characterized by non-insulin-dependent diabetes occurring typically before age 25, inherited in an autosomal dominant pattern [1]. **Correct Option: A (HNF-4 alpha)** MODY 1 is caused by a mutation in the **Hepatocyte Nuclear Factor-4 alpha (HNF-4α)** gene. This transcription factor is essential for the expression of genes involved in glucose transport and metabolism in pancreatic beta cells. Mutations lead to progressive beta-cell dysfunction and impaired insulin secretion. **Incorrect Options:** * **B. HNF-1 alpha:** This mutation causes **MODY 3**, which is the most common form of MODY worldwide. It is characterized by a low renal threshold for glucose (glycosuria). * **C. HNF-1 beta:** This mutation causes **MODY 5**, which is uniquely associated with renal cysts and genitourinary abnormalities (Renal Cysts and Diabetes Syndrome). * **D. Glucokinase (GCK):** This mutation causes **MODY 2**. It results in a "resetting" of the glucose sensor, leading to mild, stable fasting hyperglycemia that often does not require pharmacological treatment [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Most Common MODY:** MODY 3 (HNF-1α). * **Most Common in Pregnancy:** MODY 2 (GCK). * **Treatment Sensitivity:** Patients with MODY 1 and MODY 3 are exquisitely sensitive to **Sulfonylureas**, which are the first-line treatment, often allowing patients to discontinue insulin. * **Key Diagnostic Clue:** Absence of beta-cell antibodies (GAD, IA-2) and low/normal insulin levels in a young, non-obese patient with a strong family history of diabetes.

Q: Which of the following is a risk factor for developing Type 1 Diabetes mellitus?

HLA DR3. **Explanation:** Type 1 Diabetes Mellitus (T1DM) is an autoimmune disorder characterized by the destruction of pancreatic beta cells, leading to absolute insulin deficiency [1]. The primary risk factors are genetic susceptibility and environmental triggers [2]. **Why HLA DR3 is correct:** The strongest genetic association for T1DM lies within the **Major Histocompatibility Complex (MHC) Class II** genes on chromosome 6 [3]. Specifically, **HLA-DR3** and **HLA-DR4** are the most significant risk alleles. Approximately 90% of children with T1DM carry one or both of these alleles. Inheriting both (DR3/DR4 heterozygosity) confers the highest risk. These HLA molecules are involved in presenting antigens to T-cells; specific polymorphisms lead to the failure of self-tolerance and the subsequent autoimmune attack on islet cells. **Why other options are incorrect:** * **Male Gender:** T1DM does not show a strong gender predilection; it affects males and females almost equally (unlike many other autoimmune diseases which are female-dominant). * **Old Age:** T1DM typically presents in childhood or adolescence (peak incidence at puberty) [3]. While "Latent Autoimmune Diabetes in Adults" (LADA) exists, old age is a primary risk factor for **Type 2 DM**, not Type 1. * **Gestational Diabetes:** This is a risk factor for the future development of **Type 2 DM** in the mother, not Type 1. **High-Yield Clinical Pearls for NEET-PG:** * **HLA Associations:** DR3 and DR4 (Increased risk); **HLA-DQB1*0602** (Protective against T1DM). * **Autoantibodies:** Anti-GAD65 (most persistent), IA-2, and Zinc Transporter 8 (ZnT8) antibodies. * **Concordance:** The monozygotic twin concordance rate for T1DM is ~30-50% (much lower than T2DM, which is >90%) [1], [3]. * **Associated Conditions:** Always screen for other autoimmune diseases like Celiac disease and Hashimoto’s thyroiditis (Polyglandular Autoimmune Syndromes) [1].

Q: What is the pathognomic feature of hyperparathyroidism?

Subperiosteal resorption of phalanges. Primary Hyperparathyroidism (PHPT) is characterized by excessive secretion of Parathyroid Hormone (PTH), which stimulates osteoclast activity, leading to generalized bone resorption (Osteitis Fibrosa Cystica) [1]. **Why Subperiosteal Resorption is the Correct Answer:** Subperiosteal bone resorption is considered the **most specific and pathognomonic** radiographic sign of hyperparathyroidism. It occurs due to PTH-induced activation of osteoclasts in the subperiosteal region. It is most classically seen on the **radial aspect of the middle phalanges** of the 2nd and 3rd fingers. When seen on an X-ray, it is virtually diagnostic of hyperparathyroidism. **Analysis of Incorrect Options:** * **Loss of Lamina Dura (Option B):** This refers to the disappearance of the cortical bone lining the tooth socket. While it is a classic early sign of hyperparathyroidism, it is **not pathognomonic** because it can also be seen in other conditions like Paget’s disease, osteomalacia, and severe osteoporosis. * **Brown’s Tumor (Option C):** These are lytic bone lesions (osteoclastomas) filled with fibrous tissue and vascularized hemorrhage. While highly characteristic of advanced PHPT, they are a late manifestation and can mimic other giant cell tumors, making them less specific than subperiosteal resorption. * **Option A:** This is a repetition of the question stem and not a clinical feature. **NEET-PG High-Yield Pearls:** * **Salt and Pepper Skull:** A classic radiographic finding in PHPT due to multiple tiny lucencies in the calvarium. * **Rugger-Jersey Spine:** Characteristic of **Secondary Hyperparathyroidism** (seen in Chronic Kidney Disease) [2]. * **Most common cause of PHPT:** Solitary Parathyroid Adenoma (~85%) [3]. * **Biochemical Triad:** Hypercalcemia, Hypophosphatemia, and elevated PTH [2].

Q: A 35-year-old male, a known case of MEN 1, presents to the OPD with urinary stones and increased serum calcium. What is the next investigation to be done?

Secretin study. **Explanation:** The patient is a known case of **MEN 1 (Wermer Syndrome)**, which is characterized by the "3 Ps": **P**arathyroid (95% frequency), **P**ancreatic islet cell tumors, and **P**ituitary tumors. The presentation of urinary stones and hypercalcemia confirms **Primary Hyperparathyroidism** [1], the most common initial manifestation of MEN 1. Once a component of MEN 1 is identified, the clinician must screen for the other components. Among pancreatic neuroendocrine tumors (NETs) in MEN 1, **Gastrinoma (Zollinger-Ellison Syndrome)** is the most common symptomatic tumor. The **Secretin Stimulation Test** is the most sensitive and specific provocative test for diagnosing Gastrinoma. A positive result is a rise in serum gastrin >200 pg/mL above baseline. **Analysis of Incorrect Options:** * **A. Urinary metanephrine:** This is the screening test for Pheochromocytoma, which is a component of **MEN 2A and 2B**, not MEN 1. * **C. Serum calcitonin:** This is a marker for Medullary Thyroid Carcinoma (MTC), which is the hallmark of **MEN 2A and 2B**. * **D. 72-hour prolonged fasting:** This is the gold standard for diagnosing **Insulinoma**. While insulinomas occur in MEN 1, Gastrinomas are more frequent, and the Secretin study is the prioritized investigation for the most common MEN 1-associated pancreatic NET. **Clinical Pearls for NEET-PG:** * **MEN 1 Gene:** Mutation on Chromosome 11q13 (Menin protein). * **Order of appearance:** Hyperparathyroidism is usually the first clinical sign [1]. * **Gastrinoma Location:** In MEN 1, gastrinomas are often multiple and frequently located in the duodenum (Gastrinoma triangle) rather than the pancreas. * **MEN 2A:** Medullary Thyroid CA + Pheochromocytoma + Hyperparathyroidism. * **MEN 2B:** Medullary Thyroid CA + Pheochromocytoma + Mucosal Neuromas/Marfanoid habitus.

Q: Which of the following is NOT associated with hypothyroidism?

Low cholesterol. In hypothyroidism, the metabolic rate slows down, leading to characteristic biochemical changes. [1] **Explanation of the Correct Answer:** **D. Low cholesterol** is the correct answer because hypothyroidism is actually associated with **Hypercholesterolemia** (High cholesterol). Thyroid hormones normally upregulate the expression of LDL receptors on hepatocytes. [1] In a hypothyroid state, there is a decrease in the number and activity of these receptors, leading to reduced clearance of LDL from the plasma. Consequently, total cholesterol and LDL levels rise, making hypothyroidism a secondary cause of dyslipidemia. [1] **Explanation of Incorrect Options:** * **A. Low T3:** In overt hypothyroidism, both T4 and T3 levels are typically low as the thyroid gland fails to produce sufficient hormones. (Note: T4 is the more reliable diagnostic marker as T3 may remain normal in early stages). [2] * **B. High TSH:** This is the most sensitive screening test for primary hypothyroidism. Due to the lack of negative feedback from low T4/T3, the anterior pituitary increases TSH production. [2] * **C. High Triglycerides:** Hypothyroidism leads to decreased activity of **Lipoprotein Lipase (LPL)**, the enzyme responsible for clearing triglyceride-rich lipoproteins (VLDL and chylomicrons), resulting in hypertriglyceridemia. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** Hashimoto’s Thyroiditis (look for anti-TPO antibodies). * **Lipid Profile:** Expect High LDL, High Total Cholesterol, and High Triglycerides. * **Hyponatremia:** Hypothyroidism can cause dilutional hyponatremia due to impaired free water excretion (increased ADH). * **Creatine Kinase (CK):** Often elevated in hypothyroidism due to increased muscle membrane permeability (hypothyroid myopathy). * **Anemia:** Most commonly Normocytic Normochromic, but can be Macrocytic (associated Pernicious Anemia).

Q: Which of the following conditions are associated with osteoporosis?

All the above. **Explanation:** Osteoporosis is a systemic skeletal disorder characterized by low bone mass and micro-architectural deterioration. It can be primary or secondary to various endocrine and systemic conditions. **Why "All the above" is correct:** * **Cushing’s Syndrome:** Glucocorticoid excess is a leading cause of secondary osteoporosis. It acts through multiple mechanisms: decreasing osteoblast activity (bone formation), increasing osteoclast activity (bone resorption), and inhibiting intestinal calcium absorption. * **Anorexia Nervosa:** This condition leads to osteoporosis via a "triple hit": severe malnutrition (low Vitamin D and Calcium), excessive physical activity, and most importantly, **functional hypothalamic amenorrhea**. The resulting estrogen deficiency leads to rapid bone loss, similar to menopause. * **Acromegaly:** While Growth Hormone (GH) stimulates bone turnover, chronic excess leads to an imbalance where bone resorption often exceeds formation. Additionally, associated complications like hypogonadism (due to pituitary stalk compression) and hypercalciuria contribute significantly to decreased bone mineral density. **Clinical Pearls for NEET-PG:** 1. **Most common endocrine cause:** Hyperthyroidism and Hyperparathyroidism are also major triggers for secondary osteoporosis. 2. **Drug-induced:** Aside from steroids, long-term use of Heparin, Phenytoin (Anticonvulsants), and Proton Pump Inhibitors (PPIs) are high-yield causes of bone loss. 3. **Gold Standard Diagnosis:** Dual-energy X-ray absorptiometry (DEXA) scan. A **T-score of ≤ -2.5** defines osteoporosis. 4. **First-line Treatment:** Bisphosphonates (e.g., Alendronate) are generally the first-line pharmacological choice, provided there are no contraindications like achalasia or CKD.

Q: Which of the following conditions does NOT cause granulomatous hypercalcemia?

Systemic lupus erythematosus. The underlying mechanism of **granulomatous hypercalcemia** is the autonomous, extra-renal production of **1,25-dihydroxyvitamin D (Calcitriol)**. In granulomatous diseases, activated macrophages within the granuloma express the enzyme **1-alpha-hydroxylase**. Unlike the renal enzyme, this macrophage-derived enzyme is not inhibited by high levels of calcitriol or low PTH, leading to unregulated intestinal calcium absorption and hypercalcemia. * **Systemic Lupus Erythematosus (SLE) (Correct Answer):** SLE is a systemic autoimmune connective tissue disorder characterized by immune complex deposition and autoantibody production [2]. It is **not** a granulomatous disease. While SLE can rarely be associated with hypercalcemia (usually due to co-existing hyperparathyroidism or malignancy), it does not cause hypercalcemia via the 1-alpha-hydroxylase mechanism [2], [3]. * **Sarcoidosis:** The classic prototype of granulomatous hypercalcemia. Up to 10% of patients develop hypercalcemia due to high calcitriol levels produced by sarcoid granulomas [1]. * **Tuberculosis:** A common infectious cause of granulomatous hypercalcemia. Chronic inflammation and macrophage activation in TB lead to increased 1-alpha-hydroxylase activity. * **Berylliosis:** A chronic occupational lung disease caused by beryllium exposure, which histologically presents with non-caseating granulomas identical to sarcoidosis, leading to similar vitamin D-mediated hypercalcemia. **High-Yield Clinical Pearls for NEET-PG:** * **PTH Levels:** In granulomatous hypercalcemia, PTH is typically **suppressed** (low), while 1,25(OH)₂D is **elevated**. * **Treatment:** Glucocorticoids are the first-line treatment as they inhibit the 1-alpha-hydroxylase enzyme in macrophages. * **Other Causes:** Other granulomatous causes include Leprosy, Histoplasmosis, Coccidioidomycosis, and Cat-scratch disease. Certain lymphomas (Hodgkin’s) can also utilize this mechanism.

Q: Diagnostic criteria for diabetes include all EXCEPT?

A glycated hemoglobin (HbA1C) level >= 5.5%. The diagnostic criteria for Diabetes Mellitus are standardized by the American Diabetes Association (ADA) and are frequently tested in NEET-PG. [1] **Explanation of the Correct Answer:** **Option D** is the correct answer because an **HbA1C level ≥ 6.5%** is the established threshold for diagnosing diabetes, not 5.5%. A level of 5.7% to 6.4% is categorized as **Prediabetes**, while a level below 5.7% is considered normal. HbA1C reflects the average blood glucose over the preceding 2–3 months (the lifespan of an RBC). **Analysis of Incorrect Options:** * **Option A:** A **Fasting Plasma Glucose (FPG) ≥ 126 mg/dL** (7.0 mmol/L) is a standard diagnostic criterion [1]. "Fasting" is defined as no caloric intake for at least 8 hours. * **Option B:** A **Random Plasma Glucose ≥ 200 mg/dL** (11.1 mmol/L) is diagnostic *only* if the patient presents with classic symptoms of hyperglycemia (polyuria, polydipsia, unexplained weight loss) or a hyperglycemic crisis [1]. * **Option C:** A **2-hour Plasma Glucose ≥ 200 mg/dL** during a 75g Oral Glucose Tolerance Test (OGTT) is a definitive diagnostic criterion. **High-Yield Clinical Pearls for NEET-PG:** 1. **Repeat Testing:** Unless there is clear clinical diagnosis (symptomatic hyperglycemia), a second abnormal test result (either from the same sample or a different sample) is required for confirmation. 2. **Prediabetes Ranges:** FPG (100–125 mg/dL), 2-hr OGTT (140–199 mg/dL), and HbA1C (5.7–6.4%). 3. **HbA1C Limitations:** It may be inaccurate in conditions with high RBC turnover (e.g., pregnancy, hemolytic anemia, recent blood loss, or certain hemoglobinopathies). In these cases, plasma glucose criteria must be used.

Question 1

MODY 1 is caused by mutations in which of the following genes?

Accepted Answer

HNF-4 alpha

Answer

HNF-1 alpha

Answer

HNF-1 beta

Answer

Glucokinase

Question 2

Which of the following is a risk factor for developing Type 1 Diabetes mellitus?

Accepted Answer

HLA DR3

Answer

Male Gender

Answer

Old age

Answer

Gestational diabetes

Question 3

What is the pathognomic feature of hyperparathyroidism?

Accepted Answer

Subperiosteal resorption of phalanges

Answer

Pathognomic feature of hyperparathyroidism

Answer

Loss of lamina dura

Answer

Brown's tumor

Question 4

A 35-year-old male, a known case of MEN 1, presents to the OPD with urinary stones and increased serum calcium. What is the next investigation to be done?

Accepted Answer

Secretin study

Answer

Urinary metanephrine

Answer

Serum calcitonin levels

Answer

72-hour prolonged fasting

Question 5

Which of the following is NOT associated with hypothyroidism?

Accepted Answer

Low cholesterol

Answer

Low T3

Answer

High TSH

Answer

High Triglycerides

Question 6

A 42-year-old woman presents with complaints of dry skin, fatigue, and weight gain over the past 3 months. She has no significant past medical history and is not on any medications. Physical examination reveals a blood pressure of 110/70 mm Hg, pulse of 52/min, and normal heart and lung sounds. Her skin feels rough and dry. Her biochemistry is normal, but the thyroid-stimulating hormone (TSH) level is 39 mU/L (normal range: 0.5-5 mU/L). What is the most likely cause for her elevated TSH?

Accepted Answer

Autoimmune hypothyroidism

Answer

Trauma

Answer

Radioactive iodine ingestion

Answer

Parathyroid surgery

Question 7

Which of the following conditions are associated with osteoporosis?

Accepted Answer

All the above

Answer

Cushing's syndrome

Answer

Anorexia nervosa

Answer

Acromegaly

Question 8

Which of the following conditions does NOT cause granulomatous hypercalcemia?

Accepted Answer

Systemic lupus erythematosus

Answer

Tuberculosis

Answer

Sarcoidosis

Answer

Berylliosis

Question 9

Following hypophysectomy, why is vasopressin administered intramuscularly?

Accepted Answer

To replace antidiuretic hormone (ADH) that is normally secreted by the pituitary

Answer

To manage growth failure

Answer

To prevent syndrome of inappropriate antidiuretic hormone (SIADH)

Answer

To decrease cerebral edema and lower intracranial pressure

Question 10

Diagnostic criteria for diabetes include all EXCEPT?

Accepted Answer

A glycated hemoglobin (HbA1C) level >= 5.5%

Answer

A fasting plasma glucose >= 126 mg/dL

Answer

A random plasma glucose >= 200 mg/dL (in a patient with classic hyperglycemic signs)

Answer

2-hour plasma glucose >= 200 mg/dL during an oral glucose tolerance test (OGTT) with a loading dose of 75 gm

Endocrinology — MCQs

Endocrinology — MCQs

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