Endocrinology Practice Questions

Q: Radioiodine is preferred for the treatment of which of the following conditions?

Diffuse toxic goiter in patients > 45 years old. **Explanation:** Radioactive Iodine (RAI), specifically **$^{131}I$**, is a definitive treatment for hyperthyroidism. It works by emitting **beta particles**, which travel a short distance (0.5–2 mm) to selectively destroy thyroid follicular cells without damaging surrounding structures like the parathyroid glands. **Why Option D is Correct:** Radioiodine is the treatment of choice for **older patients (>35–45 years)** with diffuse toxic goiter (Graves' disease) or toxic multinodular goiter. In this age group, the risk of potential genetic damage or carcinogenesis (though largely theoretical) is minimal, and RAI provides a non-invasive, permanent cure compared to long-term antithyroid drugs. **Why Other Options are Incorrect:** * **A. Young Patients:** Surgery or antithyroid drugs (Methimazole) are generally preferred in children and adolescents to avoid long-term radiation exposure to developing tissues. * **B. Pregnancy:** **Absolute Contraindication.** RAI crosses the placenta and can destroy the fetal thyroid gland, leading to cretinism. It is also contraindicated in breastfeeding. * **C. Recent onset of toxic goiter:** In new-onset cases, especially in younger patients, a trial of antithyroid drugs (ATDs) is usually the first line to see if remission can be achieved before opting for permanent ablation. **High-Yield Clinical Pearls for NEET-PG:** * **Isotope used:** $^{131}I$ (Physical half-life: 8 days). * **Primary effect:** Beta rays (destruction); Gamma rays (used for imaging). * **Most common side effect:** Delayed hypothyroidism (requires lifelong Levothyroxine). * **Pre-treatment:** In elderly patients or those with cardiac issues, render them euthyroid with ATDs *before* RAI to prevent a Thyroid Storm caused by the release of stored hormones. * **Contraindication:** Severe Graves' ophthalmopathy (RAI can worsen the condition).

Q: Which of the following can cause osteonecrosis?

Systemic Lupus Erythematosus (SLE). **Explanation:** **Osteonecrosis (Avascular Necrosis)** is the death of bone components due to an interruption of blood supply, most commonly affecting the femoral head. **Why SLE is the Correct Answer:** Systemic Lupus Erythematosus (SLE) is a major risk factor for osteonecrosis. The pathogenesis is multifactorial, involving **vasculitis**, secondary **antiphospholipid syndrome (APLS)** leading to thrombosis, and, most significantly, the chronic use of **high-dose corticosteroids** to manage the disease. In many clinical scenarios, SLE is considered an independent risk factor even when steroid doses are controlled. **Analysis of Other Options:** * **A. Sickle Cell Anemia:** While Sickle Cell Anemia is a classic cause of osteonecrosis (due to vaso-occlusive crises), in the context of this specific question format, SLE is often highlighted as the systemic autoimmune prototype. However, it is important to note that both A and B are technically well-known causes. * **B. Corticosteroid Use:** This is the **most common** non-traumatic cause of osteonecrosis. It induces fat hypertrophy in the marrow, increasing intraosseous pressure and reducing blood flow. * **C. Diabetes Mellitus:** While DM causes various bone pathologies (like Charcot joint), it is **not** a direct or primary cause of osteonecrosis. **NEET-PG High-Yield Pearls:** * **Most common site:** Femoral head (due to retrograde blood supply via the medial circumflex femoral artery). * **Imaging of choice:** **MRI** is the most sensitive investigation for early detection (shows "double line sign"). * **X-ray finding:** "Crescent sign" (subchondral collapse) is a late finding. * **Mnemonic for Causes (PLASTIC RAGS):** **P**ancreatitis, **L**upus (SLE), **A**lcohol, **S**ickle cell, **T**rauma, **I**diopathic, **C**aisson disease, **R**adiation, **A**myloidosis, **G**aucher disease, **S**teroids.

Q: A patient presents with thyrotoxicosis and exophthalmos. What would thyroid function tests reveal?

Increased T3, increased T4, decreased TSH. **Explanation:** The clinical presentation of **thyrotoxicosis** (excess circulating thyroid hormones) combined with **exophthalmos** (proptosis) is pathognomonic for **Graves' Disease**, the most common cause of hyperthyroidism [3], [4]. **1. Why Option C is Correct:** In Graves' Disease, the body produces Thyroid Stimulating Immunoglobulins (TSI) that bind to and activate the TSH receptors on the thyroid gland [3]. This leads to the autonomous and excessive synthesis and secretion of **T3 and T4**. Through the **negative feedback mechanism**, these high levels of circulating thyroid hormones inhibit the anterior pituitary from secreting Thyroid Stimulating Hormone (TSH) [2]. Therefore, the classic biochemical profile is **elevated T3/T4 with a suppressed (decreased) TSH** [4]. **2. Why Other Options are Incorrect:** * **Option A:** Normal TSH in the presence of high T3/T4 is physiologically inconsistent due to negative feedback, unless there is a rare TSH-secreting pituitary adenoma (Secondary Hyperthyroidism), which does not present with exophthalmos [1]. * **Option B:** This profile (Low T3/T4, High TSH) represents **Primary Hypothyroidism** (e.g., Hashimoto’s Thyroiditis) [1], [2]. * **Option C:** This profile (Low T3, Normal T4, Low TSH) is often seen in **Sick Euthyroid Syndrome**, not thyrotoxicosis. **3. NEET-PG High-Yield Pearls:** * **Exophthalmos:** Specific to Graves' Disease; caused by TSH-receptor antibodies reacting with orbital fibroblasts (not seen in other causes of thyrotoxicosis like toxic multinodular goiter) [3], [4]. * **Best Initial Test:** Serum TSH (most sensitive) [2]. * **T3 Toxicosis:** In early Graves', T3 may rise before T4. * **Wolff-Chaikoff Effect:** Reduction in thyroid hormone levels caused by ingestion of a large amount of iodine.

Q: Intractable peptic ulceration with renal stones occurs in which condition?

MEN I syndrome. **Explanation:** The correct answer is **MEN I syndrome** (Wermer’s syndrome). This condition is characterized by the "3 Ps": **P**ituitary adenoma, **P**arathyroid hyperplasia/adenoma, and **P**ancreatic islet cell tumors. 1. **Why MEN I is correct:** The patient presents with two distinct pathologies: * **Intractable peptic ulceration:** Caused by a **Gastrinoma** (a pancreatic neuroendocrine tumor), which leads to Zollinger-Ellison Syndrome (ZES). * **Renal stones:** Caused by **Primary Hyperparathyroidism**, which leads to hypercalcemia and hypercalciuria, resulting in nephrolithiasis. The coexistence of these two features specifically points toward the multi-glandular involvement seen in MEN I. 2. **Why other options are incorrect:** * **Zollinger-Ellison Syndrome (A):** While ZES explains the intractable ulcers, it does not inherently cause renal stones unless it is part of MEN I. * **Parathyroid Adenoma (B):** This explains the renal stones (via hypercalcemia) but does not cause intractable peptic ulcers (though hypercalcemia can mildly increase gastrin, it rarely causes "intractable" ulceration). * **Milk-Alkali Syndrome (C):** This presents with the triad of hypercalcemia, metabolic alkalosis, and renal failure due to excessive ingestion of calcium and absorbable alkali. It does not typically cause intractable ulceration. **Clinical Pearls for NEET-PG:** * **MEN I Inheritance:** Autosomal Dominant; mutation in the *MEN1* gene (encoding the protein Menin) on Chromosome 11q13. * **Most common presentation:** Hyperparathyroidism is usually the first clinical manifestation (95% of cases). * **ZES in MEN I:** Gastrinomas in MEN I are often multiple and located in the duodenum rather than the pancreas. * **Screening:** If a patient presents with ZES, always screen for MEN I by checking serum calcium and PTH levels.

Q: Addison's disease typically:

Is an autoimmune disease. **Explanation:** **Addison’s Disease (Primary Adrenocortical Insufficiency)** occurs due to the destruction of the adrenal cortex, leading to a deficiency of cortisol, aldosterone, and adrenal androgens [3]. 1. **Why Option C is correct:** In developed countries and increasingly in urban India, **autoimmune adrenalitis** is the most common cause of Addison’s disease (accounting for ~80% of cases). It involves the destruction of the adrenal cortex by 21-hydroxylase antibodies [1]. (Note: In rural India, Tuberculosis remains a significant infectious cause) [4]. 2. **Why the other options are incorrect:** * **Option A:** Addison’s causes **hypotension** (specifically postural hypotension) due to the loss of aldosterone, leading to sodium wasting and volume depletion. * **Option B:** It causes **hyperpigmentation**, not hypopigmentation. Low cortisol triggers a compensatory increase in ACTH [1]. Since ACTH and Melanocyte-Stimulating Hormone (MSH) share a common precursor (POMC), high ACTH levels stimulate melanocytes, especially in skin creases, scars, and buccal mucosa. * **Option D:** Steroids are the **mainstay of treatment**, not contraindicated. Patients require lifelong replacement of glucocorticoids (Hydrocortisone/Prednisolone) and mineralocorticoids (Fludrocortisone) [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Electrolyte Triad:** Hyponatremia, Hyperkalemia, and Metabolic Acidosis [2]. * **Diagnosis:** The screening test of choice is the **ACTH Stimulation Test** (Cosyntropin test) [2]. A failure of cortisol to rise above 18-20 µg/dL confirms the diagnosis. * **Adrenal Crisis:** An acute emergency characterized by shock unresponsive to vasopressors; it requires immediate IV Hydrocortisone and saline resuscitation [2].

Q: A 40-year-old woman presents with lipid investigations suggestive of familial hypercholesterolemia, characterized by increased cholesterol, increased low-density lipoprotein, and normal triglycerides. This condition is associated with an increased risk for premature atherosclerosis and the presence of tuberous and tendon xanthomas. Before diagnosing familial hypercholesterolemia, secondary causes must be ruled out. Which of the following conditions is most likely to cause secondary hyperlipidemia?

Cholestatic liver disease. The patient presents with **Type IIa Hyperlipoproteinemia** (isolated elevation of LDL-C and total cholesterol), which is the hallmark of Familial Hypercholesterolemia (FH) [1]. However, secondary causes must be excluded before a genetic diagnosis is made. **1. Why Cholestatic Liver Disease is correct:** In cholestatic conditions (e.g., Primary Biliary Cholangitis), there is a significant decrease in the biliary excretion of cholesterol. This leads to the accumulation of an abnormal lipoprotein called **Lipoprotein X**, which interferes with normal lipid metabolism and causes a marked increase in total cholesterol and LDL levels [2]. This mimics the lipid profile of FH. **2. Why the other options are incorrect:** * **Alcoholism:** Typically causes **hypertriglyceridemia** (Type IV) by increasing VLDL synthesis and decreasing fatty acid oxidation. It does not cause isolated hypercholesterolemia. * **Estrogen Replacement Therapy:** Estrogens generally increase HDL and **triglycerides** (by increasing VLDL production) while lowering LDL. They do not mimic the FH profile. * **Malabsorption Syndromes:** These conditions (e.g., Celiac disease) usually lead to **hypolipidemia** due to the impaired absorption of fats and fat-soluble vitamins. **Clinical Pearls for NEET-PG:** * **High-Yield Rule:** If a question mentions isolated high LDL/Cholesterol, think **Hypothyroidism, Nephrotic Syndrome, or Cholestasis.** * **High-Yield Rule:** If a question mentions high Triglycerides, think **Diabetes Mellitus, Alcohol, or Chronic Kidney Disease.** * **Tendon Xanthomas:** These are pathognomonic for Familial Hypercholesterolemia (specifically the Achilles tendon) [1]. * **Lipoprotein X:** A specific marker for obstructive jaundice/cholestasis that causes a "pseudohypercholesterolemia" [2].

Q: The triad of diabetes mellitus, gallstones, and steatorrhea is associated with which of the following tumors?

Somatostatinomas. The correct answer is **Somatostatinomas**. These are rare neuroendocrine tumors (NETs) of the pancreas or duodenum that secrete excessive amounts of somatostatin. **Why Somatostatinomas?** Somatostatin is a potent "inhibitory" hormone [1]. Its excess leads to the classic clinical triad through the following mechanisms: 1. **Diabetes Mellitus:** Somatostatin inhibits the release of insulin and glucagon [1]. 2. **Gallstones (Cholelithiasis):** It inhibits the release of Cholecystokinin (CCK) and reduces gallbladder contractility, leading to bile stasis. 3. **Steatorrhea:** It inhibits the secretion of pancreatic enzymes and bicarbonate, leading to fat malabsorption. **Incorrect Options:** * **Gastrinomas (Zollinger-Ellison Syndrome):** Characterized by excessive gastrin, leading to refractory peptic ulcers and secretory diarrhea (due to gastric acid inactivating pancreatic lipases). * **VIPomas (Verner-Morrison Syndrome):** Characterized by **WDHA syndrome**: Watery Diarrhea, Hypokalemia, and Achlorhydria (also known as "Pancreatic Cholera"). * **Glucagonomas:** Characterized by the **4Ds**: Diabetes, Dermatitis (**Necrolytic Migratory Erythema**), Deep vein thrombosis, and Depression. **High-Yield Clinical Pearls for NEET-PG:** * **Location:** Most somatostatinomas are found in the **head of the pancreas** or the **duodenum** (often associated with NF-1). * **Psammoma Bodies:** Duodenal somatostatinomas are unique among NETs for frequently showing psammoma bodies on histology. * **Diagnosis:** Elevated fasting plasma somatostatin levels. * **Management:** Surgical resection is the treatment of choice; octreotide (a somatostatin analog) can paradoxically be used for symptom control in other NETs but is not the primary treatment here.

Q: A 23-year-old tall male presents with complaints of absent pubic hair, axillary hair, infantile genitalia, high LH, FSH levels, and XXY karyotype. What is the most probable diagnosis?

Klinefelter syndrome. **Explanation:** The clinical presentation of a tall male with signs of hypogonadism (absent secondary sexual hair, infantile genitalia) and hypergonadotropic hypogonadism (elevated LH and FSH) is classic for **Klinefelter Syndrome (47, XXY)**. **1. Why Klinefelter Syndrome is correct:** Klinefelter syndrome is the most common cause of primary hypogonadism in males [1]. The presence of an extra X chromosome leads to **dysgenesis of seminiferous tubules** (causing low inhibin and high FSH) and **damage to Leydig cells** (causing low testosterone and high LH) [2]. The lack of testosterone results in "eunuchoid" body habitus (tall stature due to delayed epiphyseal closure) and failure of secondary sexual characteristic development [1]. **2. Why other options are incorrect:** * **Vanishing Testis Syndrome (Congenital Anorchia):** While this presents with high LH/FSH and infantile genitalia, the karyotype is a normal **46, XY**, and patients are typically not tall. * **Noonan Syndrome:** Often called "Male Turner Syndrome," it presents with short stature, webbed neck, and pulmonary stenosis [3]. The karyotype is usually **46, XY**. * **Adrenal Hyperplasia (CAH):** In males, this typically causes precocious (early) puberty and virilization, not infantile genitalia or delayed puberty. **High-Yield Clinical Pearls for NEET-PG:** * **Karyotype:** Most common is 47, XXY (due to meiotic non-disjunction). * **Testicular Findings:** Characteristically **small, firm testes** (due to hyalinization and fibrosis) [1]. * **Biochemical Profile:** ↓ Testosterone, ↑ LH, ↑ FSH, ↑ Estradiol (leading to gynecomastia) [1]. * **Increased Risks:** Breast cancer (20x higher than normal males), extragonadal germ cell tumors, and autoimmune diseases (like SLE) [3]. * **Intellectual Disability:** Usually mild; IQ may be slightly lower than siblings but often within the normal range [1].

Question 1

Radioiodine is preferred for the treatment of which of the following conditions?

Accepted Answer

Diffuse toxic goiter in patients > 45 years old

Answer

Young patient

Answer

Pregnancy

Answer

Recent onset of toxic goiter

Question 2

Which of the following can cause osteonecrosis?

Accepted Answer

Systemic Lupus Erythematosus (SLE)

Answer

Sickle cell anemia

Answer

Corticosteroid use

Answer

Diabetes Mellitus

Question 3

A 70-year-old male presented with severe confusion, shortness of breath, and obtundation. Lab findings revealed moderately raised serum calcium, mildly raised serum creatinine, mildly raised BUN, normal PTH, elevated PTHrP, and an abnormal chest x-ray. Which of the following drugs can be given for the treatment of hypercalcemia?

Accepted Answer

Prednisolone

Answer

Calcitonin

Answer

Furosemide

Answer

Normal Saline

Question 4

A patient presents with thyrotoxicosis and exophthalmos. What would thyroid function tests reveal?

Accepted Answer

Increased T3, increased T4, decreased TSH

Answer

Increased T3, increased T4, normal TSH

Answer

Decreased T3, decreased T4, increased TSH

Answer

Decreased T3, normal T4, decreased TSH

Question 5

Intractable peptic ulceration with renal stones occurs in which condition?

Accepted Answer

MEN I syndrome

Answer

Zollinger Ellison syndrome

Answer

Parathyroid adenoma

Answer

Milk, alkali syndrome

Question 6

Addison's disease typically:

Accepted Answer

Is an autoimmune disease

Answer

Causes hypertension

Answer

Causes hypopigmentation

Answer

Steroids are contraindicated

Question 7

A 65-year-old lady hospitalized for cervical spondylosis was found to have a serum calcium of 12.5 mg%. Her hematocrit and KFT are normal, with a phosphate of 2.3 mg/dL. What is the most appropriate initial investigation for this patient?

Accepted Answer

Serum PTH

Answer

PTH-rP levels

Answer

Serum electrophoresis for M spike

Answer

Vitamin D3 levels

Question 8

A 40-year-old woman presents with lipid investigations suggestive of familial hypercholesterolemia, characterized by increased cholesterol, increased low-density lipoprotein, and normal triglycerides. This condition is associated with an increased risk for premature atherosclerosis and the presence of tuberous and tendon xanthomas. Before diagnosing familial hypercholesterolemia, secondary causes must be ruled out. Which of the following conditions is most likely to cause secondary hyperlipidemia?

Accepted Answer

Cholestatic liver disease

Answer

Alcoholism

Answer

Estrogen replacement therapy

Answer

Malabsorption syndromes

Question 9

The triad of diabetes mellitus, gallstones, and steatorrhea is associated with which of the following tumors?

Accepted Answer

Somatostatinomas

Answer

Gastrinomas

Answer

Vipomas

Answer

Glucagonomas

Question 10

A 23-year-old tall male presents with complaints of absent pubic hair, axillary hair, infantile genitalia, high LH, FSH levels, and XXY karyotype. What is the most probable diagnosis?

Accepted Answer

Klinefelter syndrome

Answer

Vanishing testis syndrome

Answer

Noonan syndrome

Answer

Adrenal hyperplasia

Endocrinology — MCQs

Endocrinology — MCQs

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