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: FBN1 gene mutation is seen in which of the following genetic disorders?

Marfan syndrome. ***Marfan syndrome***- The **FBN1 gene** (located on chromosome 15) encodes the protein **fibrillin-1**, a major component of the extracellular matrix, deficiency of which leads to the clinical manifestations of Marfan syndrome.- **Fibrillin-1** is integral to the formation of elastic fibers; its defect causes issues in the skeletal, ocular, and cardiovascular systems [1].*Ehlers-Danlos syndrome*- This group of disorders is primarily caused by defects in **collagen synthesis** (e.g., **COL5A1**, **COL3A1**) or processing, leading to joint hypermobility and skin hyperextensibility [2].- It is not typically associated with the **FBN1** mutation.*Homocystinuria*- This disorder is an autosomal recessive metabolic error usually caused by a deficiency of the enzyme **cystathionine beta-synthase** (CBS) [3].- It involves abnormal metabolism of **methionine** and **cysteine**, leading to high levels of **homocysteine**, and is not linked to **FBN1**.*von Hippel-Lindau syndrome*- This is a predisposition syndrome caused by a mutation in the **VHL tumor suppressor gene** (located on chromosome 3).- It predisposes patients to various tumors, including **hemangioblastomas** and **renal cell carcinoma**, and has no association with **FBN1**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 153-154. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 155-156. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 150-151.

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.

Question 1

Factor Xa is necessary for the conversion of prothrombin to thrombin?

Accepted Answer

As part of both extrinsic and intrinsic pathways

Answer

Only in the extrinsic pathway

Answer

Only in the intrinsic pathway

Answer

Only if the normal blood clotting cascade is inhibited

Question 2

S100 is a marker used in the diagnosis of which of the following conditions, EXCEPT?

Accepted Answer

Basal cell carcinoma

Answer

Melanoma

Answer

Schwannoma

Answer

Histiocytoma

Question 3

What is true about caspases?

Accepted Answer

Involved in apoptosis

Answer

Cause necrosis

Answer

Involved in pain pathway

Answer

Are cytokine inhibitors

Question 4

A trait in which the parents are clinically normal and only siblings are affected, with males and females affected in equal proportions, is characteristic of which inheritance pattern?

Accepted Answer

Autosomal Recessive (AR)

Answer

Autosomal Dominant (AD)

Answer

X-linked Dominant (XLD)

Answer

X-linked Recessive (XLR)

Question 5

Chemotherapeutic drugs can cause which of the following types of cell death?

Accepted Answer

Both necrosis and apoptosis

Answer

Only necrosis

Answer

Only apoptosis

Answer

Anoikis

Question 6

All of the following statements are true regarding hypertrophy, except:

Accepted Answer

There is an increase in the number of cells.

Answer

Occurs due to synthesis and assembly of additional intracellular components.

Answer

There is an increase in the size of the cells.

Answer

Cells capable of division respond to stress by hypertrophy and hyperplasia.

Question 7

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 8

FBN1 gene mutation is seen in which of the following genetic disorders?

Accepted Answer

Marfan syndrome

Answer

Homocystinuria

Answer

von Hippel-Lindau syndrome

Answer

Ehlers-Danlos syndrome

Question 9

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 10

Which of the following is pro-apoptotic?

Accepted Answer

Bax

Answer

Bcl-2

Answer

Bcl-xL

Answer

Mcl-1

General Pathology — MCQs

General Pathology — MCQs

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