General Pathology — MCQs

General Pathology Indian Medical PG Practice Questions and MCQs

Question 1391: What is the primary cause of hydropic change in cells?

A. Accumulation of water intracellularly (Correct Answer)
B. Fat accumulation intracellularly
C. Glycogen accumulation intracellularly
D. Lysosomal degeneration

Explanation: ***Accumulation of water intracellularly*** - Hydropic change, also known as cellular swelling, is primarily due to the **accumulation of water** within the cells caused by various pathological insults [1]. - This process is often seen in conditions such as **reversible cell injury** where the normal ion gradients are disturbed, leading to increased intracellular water [1]. *Glycogen accumulation intracellularly* - Glycogen accumulation is seen in conditions like **diabetes** or **glycogen storage diseases**, which does not lead to hydropic change. - It is characterized by the presence of **cytoplasmic granules** rather than water accumulation. *Fat accumulation intracellularly* - While fat accumulation indicates **lipidosis**, it is distinct from water accumulation and presents as **fat vacuoles** within the cell. - Commonly associated with conditions like **alcoholic liver disease**, not hydropic change. *Lysozyme degeneration* - Lysozyme degeneration relates to the breakdown of cellular components rather than an accumulation of water. - This process can lead to **cellular damage and necrosis**, but is not a direct cause of hydropic change. **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, pp. 51-53.

Question 1392: Which of the following is an example of coagulative necrosis?

A. Acute tubular necrosis (Correct Answer)
B. Stroke
C. Malignant hypertension
D. Acute pancreatitis

Explanation: ***Acute tubular necrosis*** - It is characterized by **coagulative necrosis** in the renal tubules due to ischemia or toxic injury . - This type of necrosis leads to **cellular swelling**, loss of cellular architecture, but maintains the basic outline of the tissue . *Malignant hypertension* - This condition leads to **fibrinoid necrosis** in the blood vessels rather than coagulative necrosis. - Characterized by severe hypertension causing vascular damage and organ dysfunction but does not exemplify coagulative necrosis. *Acute pancreatitis* - Associated with **fat necrosis** due to the action of pancreatic enzymes on adipose tissue. - Does not demonstrate coagulative necrosis since the process involves the dissolution of fat rather than cell structure preservation. *Stroke* - Typically results in **liquefactive necrosis**, especially in the brain, rather than coagulative necrosis. - In stroke cases, the brain tissue becomes soft and liquid-like due to necrosis, not preserving tissue architecture as seen in coagulative necrosis. **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, pp. 51-55.

Question 1393: What is the earliest detectable cellular change following injury?

A. Membrane damage
B. Diminished ATP (Correct Answer)
C. Release of lysosomal enzymes
D. Mitochondrial dysfunction

Explanation: ***Mitochondrial dysfunction*** [1] - Mitochondrial dysfunction is often the **first metabolic change** following cellular injury, impacting ATP production [1]. - Since mitochondria are crucial for energy homeostasis, dysfunction can lead to severe cellular effects and initiate the injury cascade [1]. *Diminished ATP* [1] - While diminished ATP is a consequence of injury, it is not the **initial sign**; it results from mitochondrial dysfunction [1]. - ATP depletion typically occurs **after** mitochondrial impairment has begun, indicating further progression of injury [1]. *Membrane damage* [1] - Membrane integrity can be compromised due to **various insults**, but this happens **after** mitochondrial dysfunction when the cell's economy fails [1]. - Early injury signs primarily involve **functional deficits** rather than structural changes like membrane damage [1]. *Release of lysosomal enzymes* - Release of lysosomal enzymes indicates **cell death** or severe cellular injury, which occurs later in the injury process. - It is not a primary indicator, but rather a response to **critical conditions** post-injury. **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, pp. 49-62.

Question 1394: What is the first stage of tissue damage in an alkali burn?

A. Coagulation necrosis
B. Tissue necrosis
C. Full thickness necrosis
D. Liquefactive necrosis (Correct Answer)

Explanation: ***Liquefactive necrosis*** - Alkali burns cause **liquefactive necrosis** as the **first stage of tissue damage**, which is the hallmark mechanism of alkali injury. - The alkali reacts with tissue lipids causing **saponification of fats** and **protein denaturation**, resulting in dissolution and liquefaction of tissues. - This liquefactive process allows the alkali to **penetrate deeper** into tissues progressively, causing ongoing and extensive damage as it continues to dissolve cellular structures. - This is why alkali burns are generally more severe than acid burns, despite potentially appearing less dramatic initially. *Coagulation necrosis* - **Coagulation necrosis** is characteristic of **acid burns**, not alkali burns. - Acids cause proteins to coagulate and denature, forming a **protective eschar** (dry, hard layer). - This eschar acts as a barrier that **limits penetration** of the acid into deeper tissues, often resulting in less extensive damage compared to alkali burns. *Tissue necrosis* - **Tissue necrosis** is a general term for cell death but does not specify the mechanism or type. - While liquefactive necrosis is indeed a type of tissue necrosis, this option is **too broad and non-specific** to answer what the first stage of damage is. - The question requires identification of the specific **pattern or mechanism** of necrosis, not just a general acknowledgment that cell death occurs. *Full thickness necrosis* - **Full-thickness necrosis** describes the **extent or depth** of tissue damage (involving all layers), not the mechanism or type of cellular injury. - While severe alkali burns can eventually progress to full-thickness necrosis, this is a **consequence of progressive liquefaction**, not the initial cellular process. - This term describes "how deep" rather than "how" the damage occurs.

Question 1395: Neurofibromatosis shows which of the following mode of inheritance ?

A. AD (Correct Answer)
B. AR
C. X linked dominant
D. X linked recessive

Explanation: ***AD*** - **Neurofibromatosis type 1 (NF1)** and **Neurofibromatosis type 2 (NF2)** are both classic examples of **autosomal dominant (AD)** inheritance [1]. - This means that only one copy of the altered gene (on a non-sex chromosome) is sufficient to cause the disorder, and there is a **50% chance** of passing the condition to each child [1]. *AR* - **Autosomal recessive (AR)** disorders require two copies of the altered gene (one from each parent) for the condition to manifest [1]. - Examples include **cystic fibrosis** and **sickle cell anemia**, which have a different pattern of inheritance than neurofibromatosis. *X linked dominant* - **X-linked dominant** disorders are caused by a mutation on the X chromosome, where only one copy of the mutated gene is needed for the condition to appear [1]. - These disorders typically affect females more often than males and show a specific inheritance pattern through X chromosome transmission, which is not seen in neurofibromatosis. *X linked recessive* - **X-linked recessive** disorders are also caused by mutations on the X chromosome but typically affect males more severely as they only have one X chromosome [1]. - Females are often carriers, and the inheritance pattern differs significantly from the clinical presentation and genetic transmission of neurofibromatosis. **References:** [1] 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. 53-54.

Question 1396: Which of the following conditions is characterized by the absence of Barr bodies?

A. Klinefelter syndrome
B. Down's syndrome
C. Marfan's syndrome
D. Turner syndrome (Correct Answer)

Explanation: ***Turner syndrome*** - Females with **Turner syndrome** have a 45,XO karyotype, meaning they have only one X chromosome. - Since a **Barr body** is formed from the inactivation of one X chromosome in normal females (46,XX), individuals with Turner syndrome have **no Barr bodies** due to the absence of a second X chromosome. *Klinefelter syndrome* - Individuals with **Klinefelter syndrome** typically have a 47,XXY karyotype, meaning they have two X chromosomes. - The presence of two X chromosomes leads to the formation of **one Barr body** (from inactivation of one of the two X chromosomes), making this option incorrect. *Down's syndrome* - **Down's syndrome** is caused by trisomy 21 (extra copy of chromosome 21), which is an autosomal abnormality. - The number of Barr bodies in individuals with Down's syndrome depends on their sex chromosome complement (normal pattern: 46,XX females have one Barr body, 46,XY males have none). *Marfan's syndrome* - **Marfan's syndrome** is an autosomal dominant disorder affecting connective tissue, caused by a mutation in the **FBN1 gene**. - This condition does not involve abnormalities in sex chromosomes, so the number of Barr bodies follows the normal pattern (one in 46,XX females, none in 46,XY males).

Question 1397: In which condition are positive Periodic Acid-Schiff (PAS) macrophages typically observed?

A. None of the options
B. AIDS
C. Crohn's disease
D. Whipple's disease (Correct Answer)

Explanation: ***Whipple's disease*** - **Whipple's disease** is characterized by the presence of **foamy macrophages** in the lamina propria of the small intestine [1]. - These macrophages contain intracellular rod-shaped bacilli and are strongly **Periodic Acid-Schiff (PAS)-positive** due to the presence of bacterial glycoproteins [1]. *Crohn's disease* - Crohn's disease is an **inflammatory bowel disease** characterized by transmural inflammation and non-caseating granulomas. - While macrophages are present, they are not typically **PAS-positive** in the distinctive way seen in Whipple's disease. *AIDS* - AIDS (Acquired Immunodeficiency Syndrome) is caused by the **Human Immunodeficiency Virus (HIV)** and leads to immune compromise. - While various opportunistic infections and pathologies can occur, **PAS-positive macrophages** are not a characteristic diagnostic feature of HIV/AIDS itself. *None of the options* - This option is incorrect because **Whipple's disease** clearly matches the description of having positive PAS macrophages. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 798-799.

Question 1398: What is the key pathophysiological difference between acid and alkali injuries in terms of tissue necrosis?

A. Acid injuries cause coagulative necrosis
B. Alkali injuries lead to deeper tissue damage
C. Acid injuries are less severe than alkali injuries
D. Alkali injuries cause liquefactive necrosis (Correct Answer)

Explanation: ***Alkali injuries cause liquefactive necrosis*** - **Alkali burns** result in **liquefaction necrosis**, which involves the dissolution of tissue and cells, leading to a much deeper and progressive injury as the alkali penetrates further into tissues. - This is the **key pathophysiological difference** that distinguishes alkali from acid injuries - the TYPE of necrosis (liquefactive vs coagulative). - This type of necrosis allows the alkali to continue damaging underlying tissues and can lead to more extensive and severe scarring and complications. *Acid injuries cause coagulative necrosis* - While this statement is **medically true**, it only describes what acids do without explicitly stating the **difference** or comparison with alkali injuries. - The question asks for the KEY **difference**, and this option presents only one half of the comparison. - **Acid burns** typically cause **coagulation necrosis**, forming a coagulum or eschar that precipitates proteins and creates a barrier, thereby limiting the depth of penetration. - The correct answer (alkali → liquefactive necrosis) better captures the distinguishing pathophysiological feature. *Alkali injuries lead to deeper tissue damage* - This statement is true but serves as a **consequence** of the underlying **liquefactive necrosis** rather than the primary pathophysiological mechanism itself. - The liquefaction process continuously destroys cells and extracellular matrix, enabling the caustic agent to propagate deeply into the tissue. - This describes the OUTCOME rather than the KEY pathophysiological mechanism. *Acid injuries are less severe than alkali injuries* - This is a **generalization about severity** rather than identifying the specific pathophysiological mechanism of tissue death. - While generally true due to the **coagulation necrosis** limiting the depth of penetration of acids, severity can vary based on concentration, duration of exposure, and other factors. - The formation of a protective eschar in acid burns often prevents further significant tissue destruction, unlike the progressive damage seen in alkali burns.

Question 1399: Which of the following proteins serves as the PRIMARY executioner in the apoptotic pathway by directly cleaving cellular substrates?

A. Caspases (Correct Answer)
B. Cytochrome C
C. Apaf-1
D. Bcl-2

Explanation: ***Caspases*** - **Caspases** are a family of proteases that act as the primary executioners in both the extrinsic and intrinsic apoptotic pathways, directly cleaving various cellular substrates [1]. - Once activated, **executioner caspases** (e.g., caspase-3, -6, -7) dismantle the cell by degrading key structural proteins (lamins, actins), DNA repair enzymes (PARP), and other vital components [1]. - They are the final effectors that lead to the morphological and biochemical changes characteristic of apoptosis [2]. *Apaf-1* - **Apaf-1 (Apoptotic protease activating factor 1)** is an adaptor protein that, upon binding to **cytochrome c**, forms the **apoptosome**. - The **apoptosome** then recruits and activates **initiator caspases** (e.g., caspase-9), which subsequently activate executioner caspases, but Apaf-1 does not directly cleave substrates [3]. - It functions upstream in the pathway as a scaffold protein. *Bcl-2* - **Bcl-2** is an **anti-apoptotic protein** that functions to inhibit apoptosis by preventing the release of pro-apoptotic factors like **cytochrome c** from the mitochondria [4]. - It is a regulator of apoptosis, not an executioner, and does not directly cleave cellular substrates. - It acts by maintaining mitochondrial membrane integrity. *Cytochrome C* - **Cytochrome c** is a mitochondrial intermembrane space protein that, when released into the cytoplasm, acts as a critical signaling molecule for the intrinsic apoptotic pathway [1]. - Upon release, it binds to **Apaf-1** to form the **apoptosome** and activate **caspase-9**; however, it does not directly cleave cellular substrates [2]. - It serves as a pro-apoptotic signal rather than an executioner enzyme. **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, pp. 64-65. [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. 65-67. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, p. 310. [4] 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. 80-81.

Question 1400: Caseating necrosis most commonly occurs in

A. Brain
B. Liver
C. Kidney
D. Lung (Correct Answer)

Explanation: ***lung*** - **Caseating necrosis** is classically associated with **tuberculosis**, which primarily affects the lungs [1]. - It is characterized by the presence of **granulomatous inflammation**, often leading to the formation of cavities in pulmonary tissue. *Brain* - While certain infections can lead to necrosis in the brain, they typically do not present as **caseating necrosis**, which is specific to certain conditions like tuberculosis. - The brain may show **liquefactive necrosis** or other types of necrosis, rather than **caseation**. *liver* - The liver usually shows **macrovesicular steatosis** or **apoptosis** in conditions like hepatitis, not caseating necrosis. - **Granulomatous hepatitis** can occur, but it does not typically result in **caseating** type necrosis associated with lung pathology. *kidney* - The kidneys can experience necrosis from various causes, but caseating necrosis is not typical; they are more often involved in **focal segmental glomerulosclerosis** or **acute tubular necrosis**. - Chronic kidney conditions may involve granulomas, but they usually are not characterized by **caseation** similar to that seen in pulmonary tissue. **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. 55.

Practice by Chapter

Cell Injury and Cell Death

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Adaptations of Cellular Growth

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Accumulations and Deposits

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Acute and Chronic Inflammation

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Tissue Repair and Wound Healing

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Hemodynamic Disorders

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Genetic Disorders

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Environmental Pathology

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Nutritional Diseases

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Molecular Basis of Disease

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