Accumulations and Deposits — MCQs
Which type of necrosis is characterized by deposition of immune complexes and fibrin in the walls of blood vessels?
False regarding Alzheimer's disease (AD) is:
A skin biopsy shows 'snowstorm' appearance on polarized microscopy. Which histological finding would best confirm gouty tophi?
Microvesicular fatty liver is caused by ?
Mr. Lallu, aged 54 years, who is a known diabetic patient, develops cirrhosis. There is associated skin hyperpigmentation and restrictive cardiomyopathy. Which of the following is the best initial test to diagnose this case?
Which of the following statements regarding cell aging is true?
Which type of amyloidosis is seen in the patients going through dialysis?
Size of fibrillary proteins in amyloidosis is:
Identify the correct statement regarding Amyloidosis?
In amyloidosis, beta pleated sheets can be directly visualized at the molecular level using:
Accumulations and Deposits Indian Medical PG Practice Questions and MCQs
Question 1: Which type of necrosis is characterized by deposition of immune complexes and fibrin in the walls of blood vessels?
- A. Liquefactive necrosis
- B. Coagulative necrosis
- C. Caseous necrosis
- D. Fibrinoid necrosis (Correct Answer)
Explanation: ***Fibrinoid necrosis*** - This type of necrosis is classically associated with **immune-mediated vascular damage**, where antigen-antibody complexes are deposited in arterial walls [2]. - The microscopic appearance is characterized by bright pink, amorphous material composed of **fibrin and immune complexes**, giving a fibrin-like staining pattern [1]. *Liquefactive necrosis* - Characterized by the **dissolution of dead cells into a viscous liquid mass**, often seen in bacterial infections or brain infarcts. - The necrotic tissue is replaced by inflammatory cells and fluid, rather than immune complex deposits. *Coagulative necrosis* - Occurs due to **ischemia**, leading to protein denaturation and preservation of cell outlines for a period. - It does not involve the deposition of immune complexes or fibrin in vessel walls. *Caseous necrosis* - A form of coagulative necrosis associated with **tuberculosis**, characterized by a friable, "cheese-like" appearance. - It primarily involves granulomatous inflammation and macrophage accumulation, not immune complex deposition in blood vessels. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 514-518. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 214-242.
Question 2: False regarding Alzheimer's disease (AD) is:
- A. Number of neurofibrillary tangles is associated with the severity of dementia
- B. Number of senile (neuritic) plaques correlates (increases) with age
- C. Presence of tau protein suggest neurodegeneration
- D. Extracellular inclusion (lesion) can occur in the absence of intracellular inclusions to make pathological diagnosis of AD (Correct Answer)
Explanation: ***Extracellular inclusion (lesion) can occur in the absence of intracellular inclusions to make pathological diagnosis of AD*** - A definitive pathological diagnosis of **Alzheimer's disease** requires both the presence of **extracellular amyloid plaques** and **intracellular neurofibrillary tangles** [1]. - Neither inclusion type alone is sufficient for the diagnosis, as amyloid plaques can be found in non-demented elderly individuals [1]. *Number of neurofibrillary tangles is associated with the severity of dementia* - The **density and distribution of neurofibrillary tangles** (NFTs) directly correlate with the severity of cognitive impairment and **dementia** in AD [1]. - Tangles are composed of hyperphosphorylated **tau protein** and disrupt neuronal function, leading to neurodegeneration [2]. *Number of senile (neuritic) plaques correlates (increases) with age* - The accumulation of **senile (neuritic) plaques**, composed primarily of **beta-amyloid protein**, generally increases with age, even in cognitively normal individuals [1]. - While plaques are a hallmark of AD, their mere presence is not always diagnostic of clinical dementia [1]. *Presence of tau protein suggest neurodegeneration* - The presence of **hyperphosphorylated tau protein**, especially when forming **neurofibrillary tangles**, is a strong indicator of **neurodegeneration** [2]. - **Tauopathy** is a key pathological feature in AD and other neurodegenerative diseases [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1292-1294. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 721-722.
Question 3: A skin biopsy shows 'snowstorm' appearance on polarized microscopy. Which histological finding would best confirm gouty tophi?
- A. Rhomboid crystals
- B. Malta crosses
- C. Needle-shaped crystals (Correct Answer)
- D. Apple-green birefringence
Explanation: ***Needle-shaped crystals*** - The "snowstorm" appearance on polarized microscopy, combined with the presence of **needle-shaped crystals**, is highly characteristic of **monosodium urate (MSU) crystals** seen in gouty tophi [1]. - These crystals typically show **strong negative birefringence** under polarized light [1]. *Rhomboid crystals* - **Rhomboid crystals** are characteristic of **calcium pyrophosphate dihydrate (CPPD) crystal deposition disease**, also known as pseudogout. - These crystals exhibit **positive birefringence**, differentiating them from MSU crystals. *Malta crosses* - **"Malta crosses"** are spherical aggregates of crystals, most commonly seen in **lipid-rich conditions**, such as cholesterol crystals in synovial fluid or fat emboli. - While they show birefringence, their morphology and association are distinct from gout. *Apple-green birefringence* - **Apple-green birefringence** is a characteristic finding in tissues stained with **Congo red** when viewed under polarized light, indicating the presence of **amyloid deposits**. - Amyloidosis is a protein misfolding disorder, unrelated to the crystal deposition seen in gout. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1218-1220.
Question 4: Microvesicular fatty liver is caused by ?
- A. Valproate (Correct Answer)
- B. Chronic diabetes mellitus (DM)
- C. Prolonged starvation
- D. Chronic inflammatory bowel disease (IBD)
Explanation: ***Valproate*** - **Valproate** is a known cause of **microvesicular steatosis**, particularly in children, due to its interference with mitochondrial fatty acid oxidation. - This can lead to severe liver injury, including **acute liver failure**, as it impairs the liver's ability to metabolize fats. *Chronic diabetes mellitus (DM)* - Chronic DM is commonly associated with **macrovesicular steatosis** (NAFLD), not microvesicular, due to insulin resistance and increased hepatic lipid synthesis. - Unlike microvesicular steatosis, macrovesicular type usually does not immediately impair mitochondrial function. *Prolonged starvation* - Prolonged starvation can lead to **fatty liver**, usually **macrovesicular steatosis**, as the body mobilizes fatty acids from adipose tissue. - While it stresses the liver, it rarely causes the specific **microvesicular** pattern of fat accumulation. *Chronic inflammatory bowel disease (IBD)* - IBD can cause various liver complications, but **microvesicular fatty liver** is not a characteristic feature. - Liver issues in IBD are more often related to **sclerosing cholangitis** or secondary to nutritional deficiencies and medications.
Question 5: Mr. Lallu, aged 54 years, who is a known diabetic patient, develops cirrhosis. There is associated skin hyperpigmentation and restrictive cardiomyopathy. Which of the following is the best initial test to diagnose this case?
- A. Serum ceruloplasmin
- B. Serum ferritin (Correct Answer)
- C. Serum copper
- D. Iron binding capacity
Explanation: ***Serum ferritin*** - Elevated **serum ferritin** is an excellent initial screening test for **hemochromatosis** due to its direct correlation with iron stores [1]. - The constellation of **cirrhosis**, **diabetes**, **skin hyperpigmentation**, and **restrictive cardiomyopathy** strongly points to hemochromatosis, a disorder of excessive iron accumulation [2]. *Serum ceruloplasmin* - This test is primarily used for diagnosing **Wilson's disease**, which involves copper accumulation, not iron. - While Wilson's can cause cirrhosis, the other symptoms (diabetes and skin hyperpigmentation) are not typical for this condition. *Serum copper* - **Serum copper** is another test for Wilson's disease or other copper metabolism disorders. - It does not directly assess iron stores and would not be the best initial test for suspected hemochromatosis. *Iron binding capacity* - **Total iron-binding capacity (TIBC)** measures the blood's capacity to bind iron, primarily reflecting transferrin levels. - While relevant to iron metabolism, **serum ferritin** is a more sensitive and specific initial screening test for diagnosing iron overload in hemochromatosis.
Question 6: Which of the following statements regarding cell aging is true?
- A. Free radicals cause cellular damage.
- B. Mitochondrial content decreases with age.
- C. Cell size typically decreases with aging.
- D. Lipofuscin accumulates in cells with aging. (Correct Answer)
Explanation: ***Lipofuscin accumulation in the cell*** - The accumulation of **lipofuscin** is a well-documented marker of cellular aging, representing oxidative stress and damage [1]. - Lipofuscin, often termed "age pigment," visibly increases in long-lived cells, indicating past cellular injury and degradation processes [1]. *Free radicals injury* - While **free radicals** do contribute to cellular aging, the statement is too broad; their injury is one of many factors, not a definitive marker of aging itself [3]. - Free radicals cause oxidative damage, but **lipofuscin** specifically denotes accumulated cellular debris over time [1]. *Mitochondria are increased* - Aging often leads to **mitochondrial dysfunction**, with a decrease in number and efficiency, rather than an increase. - Increased mitochondria would suggest enhanced metabolism, which contrasts with the characteristics of aging. *Size of cell increased* - Generally, cellular aging is associated with **cellular atrophy** rather than an increase in size, which might occur in specific conditions like hypertrophy [2]. - The **increase in cell size** is not a characteristic feature of aging, as older cells frequently undergo degeneration [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, p. 75. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 47-49. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 100-101.
Question 7: Which type of amyloidosis is seen in the patients going through dialysis?
- A. A-beta
- B. AL
- C. A-beta 2 (Correct Answer)
- D. aTTR
Explanation: ***A-beta 2*** - **A-beta 2 microglobulin amyloidosis** (also known as dialysis-related amyloidosis) occurs because **beta-2 microglobulin** is not effectively cleared by dialysis and accumulates in tissues [1]. - This condition primarily affects **joints, bones**, and **tendons** in long-term dialysis patients, leading to carpal tunnel syndrome, arthropathy, and bone cysts. *A-beta* - **A-beta amyloidosis** refers to the accumulation of **amyloid-beta peptides** that are characteristic of **Alzheimer's disease**, primarily affecting the brain. - This type of amyloidosis is not directly associated with renal dialysis or systemic amyloid deposits in other organs. *AL* - **AL (light chain) amyloidosis** results from the deposition of **monoclonal immunoglobulin light chains** produced by plasma cells, often associated with multiple myeloma. - While it can affect the kidneys, it is a primary amyloidosis and not caused by dialysis itself, though it can occur in patients who also have kidney failure. *aTTR* - **aTTR (transthyretin) amyloidosis** involves the deposition of **abnormal transthyretin protein**, which can be hereditary (mutated TTR) or wild-type (aging-related) [1]. - This form primarily affects the heart and nervous system and is not typically associated with chronic dialysis as its direct cause.
Question 8: Size of fibrillary proteins in amyloidosis is:
- A. 0-5 nm
- B. 7.5-10 nm (Correct Answer)
- C. 12-17 nm
- D. 18-20 nm
Explanation: ***7.5-10 nm*** - Amyloid fibrils are characteristically **non-branching**, **insoluble protein fibrils** that range in diameter from **7.5 to 10 nm**. - This specific size and morphology are crucial for their identification via **electron microscopy**, which is a key diagnostic tool for amyloidosis. *0-5 nm* - This range is generally too small for the characteristic amyloid fibrils and would likely represent **monomeric proteins** or very small aggregates. - Fibrillary structures typically need to be larger to achieve the stable, ordered beta-pleated sheet conformation seen in amyloid. *12-17 nm* - This diameter is typically **too large** for classic amyloid fibrils, which are known for their consistent size. - Fibrils in this range might suggest different types of protein aggregates or other pathological structures not characteristic of amyloid. *18-20 nm* - Fibrils of this diameter are significantly **larger than the typical amyloid fibrils** and would not be consistent with the ultrastructural definition of amyloid. - This size might be indicative of bundled fibrils or other forms of protein deposits.
Question 9: Identify the correct statement regarding Amyloidosis?
- A. Secondary amyloidosis is AL
- B. Amyloidosis is called so because of deposition of complex carbohydrates
- C. All of the options
- D. Amyloid deposits have beta pleated sheet conformation (Correct Answer)
Explanation: ### Amyloid deposits have beta-pleated sheet conformation - This **specific protein conformation** is characteristic of all amyloid fibrils, regardless of the precursor protein [1]. - The **beta-pleated sheet structure** is highly stable and resistant to enzymatic degradation, contributing to the pathologic accumulation of amyloid [1]. *Secondary amyloidosis is AL* - **Secondary amyloidosis (AA amyloidosis)** is caused by the deposition of **amyloid A protein**, which is derived from **serum amyloid A (SAA) protein** [3]. - **AL amyloidosis** is primary amyloidosis, resulting from the deposition of **immunoglobulin light chains** [2]. *Amyloidosis is called so because of deposition of complex carbohydrates* - The term "amyloid" was coined because early researchers mistakenly believed these deposits were **complex carbohydrates**, similar to starch [1]. - However, amyloidosis is actually characterized by the deposition of **abnormal proteins** that misfold and aggregate [1]. *All of the options* - This option is incorrect because the first two statements are factually inaccurate regarding the classification of amyloidosis and the composition of amyloid deposits. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 264-266. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 266-267. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 136-140.
Question 10: In amyloidosis, beta pleated sheets can be directly visualized at the molecular level using:
- A. Electron microscope
- B. X-ray crystallography (Correct Answer)
- C. Congo red stain
- D. Cryo-electron microscopy
Explanation: ***Congo red stain*** - Congo red stain is **specific** for detecting amyloid deposits, showing a characteristic **apple-green birefringence** under polarized light [1]. - The presence of **beta-pleated sheets** is a key feature of the amyloid fibrils that this stain highlights, confirming amyloidosis [1]. *Spiral electron microscope* - The **spiral electron microscope** is not a standard technique used for identifying amyloid structures or deposits. - It does not provide the **specificity** required to visualize amyloid-related beta-pleated sheets. *Electron microscope* - While electron microscopy can visualize amyloid fibrils [2], it does not specifically confirm the **beta-pleated sheet** structure like Congo red does. - This technique requires more complex preparations and does not have the same **ease of interpretation** for diagnosing amyloidosis. *X-ray crystallography* - X-ray crystallography is primarily used to determine the **three-dimensional** structure of crystalline substances, not specific to amyloid detection. - It does not provide direct evidence of **amyloid deposits** like Congo red staining does. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 268-269. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 135-136.
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