General Pathology Practice Questions

Q: A diabetic male presented with seizures. Radiological examination shows a lesion. Histopathological examination shows liquefactive necrosis. What is the most important mechanism responsible for this?

Enzymatic degradation. ***Enzymatic degradation*** - Liquefactive necrosis, common in the brain (e.g., in stroke or brain abscess as suggested by the presentation in a **diabetic** patient), is defined by the complete dissolution of dead tissue into a viscous liquid mass [1]. - This dissolution is mediated by the robust release of **hydrolytic enzymes** from inflammatory cells (like **neutrophils** in an abscess) and the deceased parenchymal cells themselves, leading to the formation of a fluid-filled cavity [1]. *Mechanical* - Mechanical injury (trauma) is a *cause* of cell death and tissue damage, but it does not describe the specific biochemical process of liquefying the dead cells. - Mechanical factors primarily lead to **coagulative necrosis** initially if blood supply is compromised, or immediate cellular disruption, which is then processed by other mechanisms. *Ischemic* - Ischemia (lack of blood flow) is a common *cause* of necrosis (e.g., cerebral infarction), which often results in liquefactive necrosis in the CNS due to its high lipid content [1]. - While ischemia is the initiating event in many cases of liquefaction (especially stroke), the actual conversion of solid dead tissue into a liquid consistency requires the action of catabolic **enzymes**. *Pressure* - Pressure usually leads to generalized **atrophy** or localized **ischemia** (e.g., pressure sores or hydrocephalus), but it is not the fundamental molecular mechanism defining liquefactive necrosis. - Severe localized pressure that compromises microcirculation leads to ischemic injury, and the subsequent type of necrosis (liquefactive or coagulative) depends on the affected organ. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1268-1269.

Q: Which genetic syndrome is caused by a deletion of the short arm of chromosome 5 (5p deletion)?

Cri-du-chat syndrome. ***Cri-du-chat syndrome*** - This syndrome is classically defined by a partial terminal deletion of the short arm of chromosome 5, designated as **5p deletion**. - Key clinical features include severe **intellectual disability**, **microcephaly**, and the characteristic high-pitched, monotonic **cat-like cry** that gives the syndrome its name. *Edward syndrome* - Edward syndrome is caused by an extra copy of chromosome 18 (**Trisomy 18**) [1]. - Clinical findings are often severe, including **micrognathia**, overlapping fingers, and **rocker-bottom feet** [1]. *Patau syndrome* - Patau syndrome is caused by an extra copy of chromosome 13 (**Trisomy 13**) [1]. - It is associated with severe midline defects such as **holoprosencephaly**, **cleft lip and palate**, and **polydactyly** [1]. *Turner syndrome* - Turner syndrome is a sex chromosome abnormality resulting from the absence of one X chromosome (45,X), making it a form of **monosomy X** [2]. - It primarily affects females, causing features like **short stature**, primary **amenorrhea** due to streak ovaries, and a **webbed neck** [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 168-169. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 175-177.

Q: Which of the following is pro-apoptotic?

Bax. ***Bax*** - Bax is a key **pro-apoptotic** effector protein from the Bcl-2 family [1]. Upon activation by stress signals, it translocates to the mitochondria and forms pores in the outer membrane [2]. - This pore formation, along with Bak, leads to **Mitochondrial Outer Membrane Permeabilization (MOMP)**, which releases **cytochrome c** and initiates the intrinsic caspase cascade of apoptosis [3]. *Bcl-2* - Bcl-2 is the prototypical **anti-apoptotic** protein that prevents apoptosis by binding to and inhibiting pro-apoptotic proteins like Bax and Bak [2]. - By preventing MOMP, it maintains mitochondrial integrity and is often overexpressed in cancers, such as follicular lymphoma, contributing to cell survival [2]. *Bcl-xL* - Bcl-xL is another major **anti-apoptotic** protein in the Bcl-2 family, with a function very similar to Bcl-2 [2]. - It promotes cell survival by sequestering pro-apoptotic BH3-only proteins and preventing the activation of Bax and Bak. *Mcl-1* - Mcl-1 (Myeloid cell leukemia-1) is a critical **anti-apoptotic** protein that is essential for the survival of various cell types [2]. - Its primary role is to inhibit apoptosis by neutralizing pro-apoptotic proteins, and its high levels are often associated with tumor progression and resistance to chemotherapy [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, pp. 65-67. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, p. 310. [3] 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.

Q: Caspase-1 mediated cell death with inflammation is known as

Pyroptosis. ***Pyroptosis*** - This form of programmed cell death is characterized by the formation of an **inflammasome** complex [2], activating **Caspase-1** [1]. - Caspase-1 activation leads to the cleavage of pro-IL-1$\beta$ and pro-IL-18 into their active forms, resulting in a highly **inflammatory** process and cell lysis [1]. *Necroptosis* - This programmed, but non-apoptotic, cell death is mediated by the **RIPK1/RIPK3/MLKL** signaling pathway, involving receptor-interacting protein kinases [1]. - It is morphologically similar to necrosis but can be pharmacologically inhibited; it is **Caspase-independent** [3]. *Ferroptosis* - Ferroptosis is a form of regulated necrosis driven by **iron-dependent lipid peroxidation**. - It is characterized by the accumulation of reactive oxygen species and is typically **Caspase-independent**. *Necrosis* - Necrosis is an uncontrolled, **non-programmed** form of cell death resulting from acute cellular injury or pathology (e.g., ischemia). - It involves cell swelling, rupture of the plasma membrane, and leakage of cellular contents, leading to massive local inflammation, but is **not directly mediated by Caspase-1**. **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. 71. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, p. 196. [3] 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. 69-71.

Q: A middle-aged man from an endemic region presents with progressive swelling of the lower limb. A peripheral blood smear shows the following structure. What is the most likely cause of his limb swelling?

Lymphatic obstruction. ***Lymphatic obstruction*** - The image displays **microfilariae** (suggesting **Lymphatic Filariasis**), where the adult worms settle in the lymphatics, physically blocking flow. - This obstruction results in chronic, progressive edema (known as **lymphedema** or **elephantiasis**) due to the failure of lymphatic drainage in the affected limb. *Hypoalbuminemia* - Edema from **hypoalbuminemia** is due to low plasma oncotic pressure and typically results in generalized, pitting edema, which is not characteristic of chronic, localized filarial swelling. - While malnutrition might co-exist, the core pathology shown by the presence of **microfilariae** points specifically to mechanical lymphatic blockage. *Hypoproteinemia* - **Hypoproteinemia** is a general cause of edema via reduced **oncotic pressure**, leading to fluid shift into the interstitial spaces, usually causing generalized rather than localized swelling. - This systemic cause does not account for the specific parasitic damage to the lymphatics demonstrated by the presence of the **filarial worms**. *increased hydrostatic pressure* - Increased hydrostatic pressure (e.g., in conditions like DVT or CHF) leads to fluid leakage from capillaries, causing pitting edema. - The root cause here is the parasitic **destruction and obstruction of lymph nodes and channels**, which specifically impairs lymph return, not capillary hydrostatic pressure regulation.

Q: Which of the following types of cell death involves activation of caspase enzymes?

Apoptosis and Pyroptosis. ***Apoptosis and Pyroptosis*** - **Apoptosis** is the classic caspase-dependent programmed cell death pathway [1] - Involves **initiator caspases** (Caspase-8, Caspase-9) and **executioner caspases** (Caspase-3, -6, -7) - Characterized by cell shrinkage, chromatin condensation, and apoptotic body formation - **Pyroptosis** is an inflammatory form of programmed cell death that is strictly caspase-dependent [2] - Mediated by **inflammatory caspases** (Caspase-1, -4, -5, -11) [2] - Involves cleavage of Gasdermin-D leading to membrane pore formation - Triggered by inflammasome activation (particularly NLRP3) *Necrosis and Apoptosis* - **Necrosis** is caspase-independent and represents unregulated cell death from acute injury - Characterized by cell swelling, membrane rupture, and inflammatory response - Does not involve programmed activation of caspase enzymes *Apoptosis and necroptosis* - **Necroptosis** is a regulated form of necrotic cell death that occurs in a **caspase-independent** manner [2] - Executed through RIPK1-RIPK3-MLKL kinase pathway [2] - Typically occurs when caspase activity is inhibited or blocked *Apoptosis only* - Incomplete answer as **pyroptosis** is also inherently caspase-dependent - Pyroptosis uses inflammatory caspases (Caspase-1/4/5) distinct from apoptotic caspases - Both pathways represent distinct forms of caspase-mediated programmed cell death **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. 64-67. [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, p. 71.

Question 1

Autopsy of a specimen shows pale infarction. Pale infarct is seen in all of the following organs, EXCEPT:

Accepted Answer

Lung

Answer

Heart

Answer

Spleen

Answer

Kidney

Question 2

A 1-year-old boy presents with a delay in motor development. Progressive muscle weakness and blindness ensue, and the patient dies within a year. The brain at autopsy shows swollen neurons that contain numerous lysosomes filled with lipid. Which of the following is the most likely diagnosis?

Accepted Answer

Tay-Sachs disease

Answer

AL amyloidosis

Answer

Hurler syndrome

Answer

Phenylketonuria

Question 3

A 40-year-old female patient complains of excessive bleeding and drowsiness following a road traffic accident 5 hours ago, with a lacerated wound on the lower back region. General physical examination reveals: Blood pressure - 80/60 mmHg, Jugular venous pressure - low, Pulsus paradoxus - present, Cardiac output - Increased. The patient is in which type of shock?

Accepted Answer

Distributive

Answer

Neurogenic

Answer

Obstructive

Answer

Hypovolemic

Question 4

A diabetic male presented with seizures. Radiological examination shows a lesion. Histopathological examination shows liquefactive necrosis. What is the most important mechanism responsible for this?

Accepted Answer

Enzymatic degradation

Answer

Ischemic

Answer

Mechanical

Answer

Pressure

Question 5

Which genetic syndrome is caused by a deletion of the short arm of chromosome 5 (5p deletion)?

Accepted Answer

Cri-du-chat syndrome

Answer

Edward syndrome

Answer

Turner syndrome

Answer

Patau syndrome

Question 6

Which of the following is pro-apoptotic?

Accepted Answer

Bax

Answer

Bcl-2

Answer

Bcl-xL

Answer

Mcl-1

Question 7

Which of the following is a change seen in irreversible cell injury?

Accepted Answer

Amorphous density of mitochondria

Answer

Cellular Swelling

Answer

Bleb formation

Answer

Clumping of chromatin

Question 8

Caspase-1 mediated cell death with inflammation is known as

Accepted Answer

Pyroptosis

Answer

Necroptosis

Answer

Necrosis

Answer

Ferroptosis

Question 9

A middle-aged man from an endemic region presents with progressive swelling of the lower limb. A peripheral blood smear shows the following structure. What is the most likely cause of his limb swelling?

Accepted Answer

Lymphatic obstruction

Answer

Hypoalbuminemia

Answer

Hypoproteinemia

Answer

Increased hydrostatic pressure

Question 10

Which of the following types of cell death involves activation of caspase enzymes?

Accepted Answer

Apoptosis and Pyroptosis

Answer

Necrosis and Apoptosis

Answer

Apoptosis only

Answer

Apoptosis and necroptosis

General Pathology — MCQs

General Pathology — MCQs

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