Endocrinology — MCQs

A 20-year-old male patient presents with a chief complaint of abdominal pain. General examination reveals xanthomas present in clusters on the back, buttocks, arms, and legs. On percussion, hepatomegaly and splenomegaly can be appreciated. Blood investigations show decreased LDL levels and normal HDL levels. What is the most probable diagnosis?

Q209Medium

An obese NIDDM patient presents with a Fasting Blood Sugar (FBS) of 180 mg% and Postprandial Blood Sugar (PPBS) of 260 mg%. What is the appropriate management?

Q210Medium

Which of the following trace elements is associated with hypothyroidism in the sub-Himalayan region?

Endocrinology Indian Medical PG Practice Questions and MCQs

Question 201: A 52-year-old woman presents with complaints of fatigue, flank pain, headache, hematuria, and abdominal pain. A sestamibi scan demonstrates persistent uptake in the right superior parathyroid gland at 2 hours. Which of the following laboratory values is most suggestive of her diagnosis?

A. Serum acid phosphatase above 120 IU/L
B. Serum alkaline phosphatase above 120 IU/L
C. Urinary calcium below 100 mg/day
D. Serum calcium above 11 mg/dL (Correct Answer)

Explanation: ### Explanation **Diagnosis: Primary Hyperparathyroidism (PHPT)** The clinical presentation of fatigue, flank pain (renal stones), abdominal pain (peptic ulcers/pancreatitis), and hematuria, combined with a **Sestamibi scan** showing persistent uptake in a parathyroid gland, is classic for **Primary Hyperparathyroidism** [2]. #### 1. Why Option D is Correct The hallmark of PHPT is **hypercalcemia** (Serum Calcium >10.5 mg/dL) associated with inappropriately elevated or high-normal Parathyroid Hormone (PTH) levels [2]. A serum calcium level above 11 mg/dL is the most characteristic laboratory finding in a symptomatic patient [2]. PTH increases bone resorption, renal calcium reabsorption, and intestinal calcium absorption (via Vitamin D activation), leading to elevated systemic calcium levels [1]. #### 2. Why Other Options are Incorrect * **Option A:** Serum acid phosphatase is a marker for prostatic pathology or certain bone resorptive states but is not a diagnostic marker for PHPT. * **Option B:** While Alkaline Phosphatase (ALP) can be elevated in severe PHPT with significant bone involvement (**Osteitis Fibrosa Cystica**), it is not as sensitive or specific as hypercalcemia. * **Option C:** PHPT typically causes **Hypercalciuria** (Urinary calcium >250–300 mg/day) because the high filtered load of calcium exceeds the kidneys' reabsorptive capacity. Low urinary calcium (<100 mg/day) suggests **Familial Hypocalciuric Hypercalcemia (FHH)**, a key differential [3]. #### 3. NEET-PG High-Yield Pearls * **Most common cause of PHPT:** Solitary Adenoma (85%). * **Classic Mnemonic:** "Stones (renal), Bones (aches), Groans (abdominal pain), and Psychic Overtones (depression/fatigue)." * **Imaging:** Sestamibi scan is the investigation of choice for **localization** before surgery, not for diagnosis [2]. * **Biochemical Profile:** ↑ Calcium, ↓ Phosphate, ↑ PTH, ↑ Urinary cAMP, and 1,25-(OH)₂ Vitamin D [1]. * **Chloride/Phosphate Ratio:** A ratio >33 is highly suggestive of PHPT.

Question 202: What is the role of insulin in type 2 diabetes mellitus?

A. Acute illness (Correct Answer)
B. Polyuria
C. Secondary failure of oral hypoglycemic agents
D. Obese patient

Explanation: ### Explanation In Type 2 Diabetes Mellitus (T2DM), insulin is not typically the first-line treatment but becomes mandatory under specific clinical circumstances. **Why "Acute Illness" is correct:** During acute illnesses (such as myocardial infarction, severe infections/sepsis, or major surgery), the body enters a state of high metabolic stress [1]. This triggers the release of counter-regulatory hormones (cortisol, catecholamines, glucagon), which induce significant insulin resistance and hyperglycemia. In these "stress states," oral hypoglycemic agents (OHAs) are often insufficient, contraindicated (e.g., Metformin in sepsis due to lactic acidosis risk), or unable to provide the rapid, titratable glycemic control required [2]. Insulin is the preferred agent to maintain euglycemia and promote recovery [2]. **Analysis of Incorrect Options:** * **Polyuria:** This is a symptom of osmotic diuresis due to hyperglycemia [3]. It is initially managed with lifestyle modifications and OHAs. Insulin is only required if OHAs fail to control the underlying glucose levels [4]. * **Secondary failure of OHAs:** While insulin is used when OHAs fail, the question asks for a specific "role" or indication. In the hierarchy of urgent clinical needs, an acute illness is a definitive, immediate indication for insulin transition, whereas OHA failure is a gradual progression [4]. * **Obese patient:** Obesity is characterized by insulin resistance. The primary treatment involves weight loss and insulin-sensitizing agents like Metformin or GLP-1 agonists. Insulin is often avoided initially in obese patients as it can promote further weight gain. **Clinical Pearls for NEET-PG:** * **HHS vs. DKA:** While DKA is classic for Type 1, **Hyperosmolar Hyperglycemic State (HHS)** is the life-threatening emergency in Type 2, often precipitated by acute illness, requiring aggressive IV insulin and fluids. * **Metformin Holiday:** Always withhold Metformin 48 hours before and after major surgery or radiocontrast administration to prevent lactic acidosis [2]. * **HbA1c Threshold:** According to ADA guidelines, consider starting insulin immediately if the patient is symptomatic or if HbA1c is **>10%** or blood glucose is **≥300 mg/dL** [3].

Question 203: Which of the following conditions is characterized by the clinical feature described?

A. Pheochromocytoma
B. Adrenal incidentaloma
C. Neuroblastoma (Correct Answer)
D. Medullary thyroid cancer

Explanation: ***Neuroblastoma*** - **Raccoon eyes** (bilateral periorbital ecchymosis) is a pathognomonic sign of neuroblastoma with **orbital metastases**, commonly seen in pediatric patients. - Elevated **urinary VMA/HVA** (vanillylmandelic acid/homovanillic acid) levels and **catecholamine secretion** are characteristic biochemical findings. *Pheochromocytoma* - Primarily presents with **hypertensive crises**, **sweating**, and **headaches** due to excessive catecholamine release. - Does not typically cause **orbital metastases** or raccoon eyes, even though it also secretes catecholamines. *Adrenal incidentaloma* - Usually **asymptomatic** and discovered incidentally on imaging studies. - Lacks the characteristic **periorbital ecchymosis** and catecholamine-related symptoms seen in this case. *Medullary thyroid cancer* - Commonly presents with **diarrhea**, **flushing**, and elevated **calcitonin** levels due to excessive calcitonin secretion. - Does not cause **orbital metastases** or raccoon eyes, and primarily affects the thyroid gland rather than adrenal tissue.

Question 204: Which joint is commonly involved in diabetic arthropathy?

A. Ankle
B. Knee
C. Shoulder
D. Foot (Correct Answer)

Explanation: **Explanation:** The correct answer is **Foot**. Diabetic arthropathy primarily manifests as **Charcot Neuroarthropathy (Charcot Joint)**, which most frequently involves the small joints of the foot and the ankle complex [1]. **Why the Foot is the Correct Answer:** The underlying pathophysiology involves a combination of **peripheral neuropathy** (loss of pain and proprioception) and **autonomic neuropathy** (increased blood flow leading to bone resorption). Repetitive microtrauma to a desensitized foot leads to progressive joint destruction, subluxation, and characteristic deformities like the "rocker-bottom foot." The **tarsometatarsal (Lisfranc) and metatarsophalangeal joints** are the most common sites of involvement [1]. **Analysis of Incorrect Options:** * **Ankle:** While the ankle can be involved in Charcot joint, it is statistically less common than the midfoot and forefoot joints [1]. * **Knee:** Charcot joint of the knee is more classically associated with **Tabes Dorsalis (Syphilis)** rather than Diabetes Mellitus. * **Shoulder:** Shoulder involvement in diabetes is typically associated with **Adhesive Capsulitis (Frozen Shoulder)** or calcific tendonitis, which are soft tissue disorders rather than the destructive arthropathy (Charcot) implied by the term "diabetic arthropathy." **High-Yield Clinical Pearls for NEET-PG:** * **Rocker-bottom foot:** A classic deformity caused by the collapse of the midfoot arch in Charcot joint [1]. * **Differential Diagnosis:** An acute Charcot foot often presents as red, hot, and swollen, frequently misdiagnosed as **cellulitis or osteomyelitis**. * **Key Distinguishing Factor:** In Charcot, the redness usually subsides when the foot is elevated for 5–10 minutes (unlike cellulitis). * **Treatment:** The gold standard for acute Charcot neuroarthropathy is **Total Contact Casting (TCC)** to offload the joint.

Question 205: A 53-year-old man presents for a physical. His father had diabetes and died of congestive heart failure, reportedly due to "bronze diabetes." The patient complains of vague fatigue and arthralgias. Which test would you order to confirm the suspicion of hereditary hemochromatosis?

A. Antimitochondrial antibodies
B. Ceruloplasmin
C. Heterophil antibodies
D. Transferrin saturation (Correct Answer)

Explanation: **Explanation:** The clinical presentation of fatigue, arthralgias, and a family history of "bronze diabetes" (the triad of cirrhosis, hyperpigmentation, and diabetes) strongly suggests **Hereditary Hemochromatosis (HH)** [2]. This is an autosomal recessive disorder, most commonly due to a mutation in the **HFE gene**, leading to excessive intestinal iron absorption and organ deposition [1]. **Why Transferrin Saturation is Correct:** The initial screening test of choice for HH is **Transferrin Saturation (TSAT)**. A value **>45%** is highly sensitive and indicates iron overload. If TSAT is elevated, serum ferritin is measured [1]. Confirmation is typically achieved through **HFE gene mutation analysis** (C282Y/H63D) [1], [2]. While liver biopsy was previously the gold standard, it is now reserved for assessing fibrosis or when genetic testing is inconclusive [1]. **Why Incorrect Options are Wrong:** * **Antimitochondrial antibodies (AMA):** The hallmark of Primary Biliary Cholangitis (PBC), which presents with pruritus and jaundice, not iron overload. * **Ceruloplasmin:** Low levels are seen in Wilson’s Disease (copper overload), which typically presents in younger patients with neurological symptoms and Kayser-Fleischer rings. * **Heterophil antibodies:** Used for the Monospot test to diagnose Infectious Mononucleosis (EBV). **NEET-PG High-Yield Pearls:** * **Most common mutation:** C282Y (substitution of tyrosine for cysteine) [1], [2]. * **Classic Triad:** Cirrhosis, Diabetes ("Bronze Diabetes"), and Skin Hyperpigmentation [2]. * **Arthropathy:** Characterized by "hook-like" osteophytes on X-ray, commonly involving the 2nd and 3rd MCP joints. * **Cardiac involvement:** Most commonly presents as Restrictive Cardiomyopathy (early) or Dilated Cardiomyopathy (late). * **Treatment:** Therapeutic phlebotomy is the mainstay of management [1].

Question 206: A patient presents with hands that are developmentally delayed and a short, stocky build. Which of the following is the most likely diagnosis?

A. Achondroplastic dwarf
B. Down syndrome
C. Klinefelter's syndrome
D. Pseudohypoparathyroidism (Correct Answer)

Explanation: The clinical presentation described—short, stocky build and developmental skeletal abnormalities—is characteristic of **Albright’s Hereditary Osteodystrophy (AHO)**, the phenotypic manifestation of **Pseudohypoparathyroidism (PHP) Type 1a**. **1. Why Pseudohypoparathyroidism is correct:** PHP is caused by end-organ resistance to Parathyroid Hormone (PTH). Patients typically present with hypocalcemia and hyperphosphatemia despite elevated PTH levels. The AHO phenotype includes a short, stocky habitus, round facies, developmental delay, and **brachydactyly** (specifically shortening of the 4th and 5th metacarpals/metatarsals). This explains the "developmentally delayed hands" and "short, stocky build" mentioned in the question. **2. Why the other options are incorrect:** * **Achondroplastic dwarf:** While these patients have a short build, it is characterized by disproportionate dwarfism (rhizomelic shortening) and a large head with frontal bossing. They do not typically have the biochemical or intellectual delays associated with PHP. * **Down syndrome:** Although associated with short stature and intellectual disability, the classic hand finding is a **simian crease** and clinodactyly, not the specific brachydactyly/stocky build seen in AHO. * **Klinefelter's syndrome:** These patients are typically **tall** with long extremities (eunuchoid habitus), which is the opposite of the "short, stocky" description [1]. **Clinical Pearls for NEET-PG:** * **Archibald’s Sign:** Dimpling over the knuckles of the 4th and 5th metacarpals when making a fist (due to brachydactyly), a classic sign of PHP. * **Pseudopseudohypoparathyroidism (PPHP):** Patients have the AHO phenotype but **normal** biochemical levels (calcium/PTH) because the defect is inherited paternally. * **Genetics:** PHP Type 1a involves a mutation in the **GNAS1 gene**, which encodes the alpha subunit of the Gs protein.

Question 207: Which of the following is structurally related to insulin-like growth factors I and II?

A. Preproinsulin
B. Proinsulin (Correct Answer)
C. Insulin
D. C peptide

Explanation: **Explanation:** The correct answer is **Proinsulin**. **Why Proinsulin is correct:** Insulin-like growth factors (IGF-I and IGF-II) are polypeptide hormones that share significant structural homology with **proinsulin** [1]. Proinsulin consists of three chains: the A-chain, the B-chain, and a connecting C-peptide. Similarly, IGFs are single-chain polypeptides that contain domains analogous to the A and B chains of insulin, linked by a connecting peptide (C-domain) [1]. Unlike proinsulin, however, the C-domain in IGFs is not cleaved during processing, meaning IGFs remain as single-chain molecules that structurally resemble the precursor form of insulin [1]. **Why the other options are incorrect:** * **Preproinsulin (A):** This is the initial translation product that includes a signal peptide. The signal peptide is cleaved in the endoplasmic reticulum to form proinsulin; therefore, the mature IGF structure specifically mirrors the proinsulin stage. * **Insulin (C):** Mature insulin consists of two separate polypeptide chains (A and B) held together by disulfide bonds after the C-peptide has been removed [2]. Because IGFs retain their connecting peptide, they are more closely related to the precursor (proinsulin) than the mature hormone [1]. * **C-peptide (D):** While IGFs have a "C-domain," it shows very little sequence homology with the actual human C-peptide found in proinsulin. **High-Yield NEET-PG Pearls:** * **IGF-I (Somatomedin C):** Primarily produced in the liver under the influence of Growth Hormone (GH) [2]. It mediates most of the growth-promoting effects of GH. * **Receptor Homology:** The IGF-I receptor is a tyrosine kinase receptor, structurally very similar to the insulin receptor [3]. * **Clinical Correlation:** In cases of **Islet Cell Tumors (Non-islet cell tumor hypoglycemia - NICTH)**, tumors may secrete "Big IGF-II," which can bind to insulin receptors and cause profound hypoglycemia.

Question 208: A 20-year-old male patient presents with a chief complaint of abdominal pain. General examination reveals xanthomas present in clusters on the back, buttocks, arms, and legs. On percussion, hepatomegaly and splenomegaly can be appreciated. Blood investigations show decreased LDL levels and normal HDL levels. What is the most probable diagnosis?

A. Familial Chylomicronemia Syndrome (FCS) - Type I
B. Familial Dysbetalipoproteinemia (FDBL) - Type III (Correct Answer)
C. Familial Hypertriglyceridemia (FHTG) - Type IV
D. Familial Combined Hyperlipidemia (FCHL) - Type IIb

Explanation: ### Explanation **Correct Answer: B. Familial Dysbetalipoproteinemia (FDBL) - Type III** **Why it is correct:** Familial Dysbetalipoproteinemia (Type III Hyperlipoproteinemia) is characterized by a defect in **Apolipoprotein E (ApoE)**, specifically the **E2/E2 isoform**, which leads to impaired clearance of chylomicron remnants and IDL (VLDL remnants). [2] * **Clinical Presentation:** The hallmark sign is **Eruptive Xanthomas** (clusters on buttocks/arms) and pathognomonic **Palmar Xanthomas** (orange-yellow streaks in palmar creases). * **Organomegaly:** Accumulation of remnants in the reticuloendothelial system leads to hepatosplenomegaly. * **Lipid Profile:** Because IDL is not converted to LDL efficiently, **LDL levels are characteristically low or normal**, while total cholesterol and triglycerides are both elevated (often in a 1:1 ratio) [1], [2]. **Why incorrect options are wrong:** * **A. Type I (FCS):** Caused by LPL or ApoC-II deficiency. While it presents with eruptive xanthomas and hepatosplenomegaly, it is characterized by massive chylomicronemia and milky plasma, not specifically low LDL. * **C. Type IV (FHTG):** Characterized by isolated elevation of VLDL [2]. It usually lacks the prominent xanthomas and hepatosplenomegaly seen in this case and typically presents with normal or slightly elevated LDL. * **D. Type IIb (FCHL):** Characterized by **elevated LDL** and VLDL [2]. The question explicitly states LDL is decreased, which rules out Type II. **NEET-PG High-Yield Pearls:** * **ApoE Genotype:** Most patients are homozygous for **ApoE2**. * **Broad Beta Disease:** On electrophoresis, Type III shows a "broad beta band" (accumulation of IDL) [2]. * **Diagnosis:** Look for the "1:1 ratio" of Cholesterol to Triglycerides and low LDL. * **Clinical Sign:** Palmar xanthomas (Xanthoma striatum palmare) are the most specific physical finding for Type III.

Question 209: An obese NIDDM patient presents with a Fasting Blood Sugar (FBS) of 180 mg% and Postprandial Blood Sugar (PPBS) of 260 mg%. What is the appropriate management?

A. Glibenclamide
B. Diet therapy and exercise (Correct Answer)
C. Diet therapy, exercise, and Metformin
D. Chlorpropamide

Explanation: ### Explanation **Correct Answer: B. Diet therapy and exercise** **Why it is correct:** In a newly diagnosed or currently uncontrolled obese patient with Non-Insulin Dependent Diabetes Mellitus (NIDDM/Type 2 DM), the **first-line management** according to standard guidelines (ADA/RSSDI) is lifestyle modification. This includes therapeutic lifestyle changes (TLC) such as medical nutrition therapy (diet) and regular physical activity [1]. In obese patients, weight loss of even 5–10% can significantly improve insulin sensitivity and glycemic control [2]. For many patients, these measures alone are sufficient to bring blood glucose levels toward the target range before initiating pharmacological therapy. **Why the other options are incorrect:** * **C. Diet therapy, exercise, and Metformin:** While Metformin is the first-line drug of choice for obese diabetics [3], standard management protocols (especially in the context of NEET-PG questions) emphasize a trial of lifestyle modification for 3–6 months before adding pharmacotherapy, unless the HbA1c is very high (>9%) or the patient is symptomatic. * **A. Glibenclamide & D. Chlorpropamide:** These are Sulfonylureas. They are generally avoided as first-line agents in obese patients because they cause **weight gain** and carry a risk of hypoglycemia. Chlorpropamide is a first-generation sulfonylurea and is now rarely used due to its long half-life and side effects (SIADH, disulfiram-like reaction). **Clinical Pearls for NEET-PG:** * **First-line drug for Obese T2DM:** Metformin (it is weight-neutral or promotes weight loss). * **Mechanism of Metformin:** Primarily decreases hepatic gluconeogenesis and increases peripheral insulin sensitivity via AMPK activation. * **Dawn Phenomenon:** Early morning hyperglycemia due to nocturnal GH surge; managed by increasing evening insulin dose. * **Somogyi Effect:** Rebound hyperglycemia following nocturnal hypoglycemia; managed by decreasing evening insulin dose.

Question 210: Which of the following trace elements is associated with hypothyroidism in the sub-Himalayan region?

A. Copper
B. Iron
C. Zinc
D. Selenium (Correct Answer)

Explanation: **Explanation:** The correct answer is **Selenium (D)**. **Why Selenium is Correct:** Selenium is a critical trace element for thyroid function. It is a key component of **Selenocysteine**, which is found in the active sites of **Iodothyronine Deiodinases** (Type 1, 2, and 3). These enzymes are responsible for the peripheral conversion of T4 (inactive) to T3 (active). Additionally, **Glutathione Peroxidase**, a selenium-dependent enzyme, protects the thyroid gland from oxidative damage caused by hydrogen peroxide during thyroid hormone synthesis. In the **sub-Himalayan region**, the soil is deficient not only in Iodine but also in Selenium. Combined deficiency exacerbates hypothyroidism and is specifically linked to **Myxedematous Cretinism**. Without selenium, deiodinase activity drops, and oxidative stress damages thyroid follicular cells, worsening the effects of iodine deficiency. **Why Other Options are Incorrect:** * **Copper (A):** While copper is involved in energy metabolism (Cytochrome c oxidase), its deficiency is primarily associated with microcytic anemia and myeloneuropathy, not regional hypothyroidism. * **Iron (B):** Iron is a cofactor for **Thyroid Peroxidase (TPO)** [2]. While iron deficiency can impair thyroid metabolism, it is a global nutritional issue and not the specific trace element classically associated with sub-Himalayan endemic goiter/cretinism in this context. * **Zinc (C):** Zinc is required for the T3 receptor to bind to DNA (zinc fingers). While deficiency can affect thyroid hormone levels, it is not the primary geographical driver of hypothyroidism in the Himalayan belt. **High-Yield Clinical Pearls for NEET-PG:** * **Enzyme Link:** Selenium = Deiodinases & Glutathione Peroxidase. * **Kashin-Beck Disease:** An osteoarthropathy also associated with Selenium deficiency. * **Keshan Disease:** A cardiomyopathy associated with Selenium deficiency. * **Sub-Himalayan Goiter Belt:** Always consider dual deficiency of Iodine and Selenium. [1]

Practice by Chapter

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Multiple Endocrine Neoplasia

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Endocrine Emergencies

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