General Pathology Practice Questions

Q: What is the Leiden factor?

Factor V. **Explanation:** **Factor V Leiden** is the most common inherited cause of hypercoagulability (thrombophilia) among Caucasians [1]. It is caused by a specific point mutation in the Factor V gene (G1691A), which results in the substitution of arginine by glutamine at position 506 [1]. **Why Option D is Correct:** Under normal physiological conditions, **Activated Protein C (APC)** inactivates Factor Va and Factor VIIIa to limit clot formation. In Factor V Leiden, the mutation alters the cleavage site on Factor V where Protein C normally binds. This renders Factor V resistant to inactivation by APC (**APC Resistance**) [1]. Consequently, Factor V remains active in the circulation for longer periods, leading to a prothrombotic state and increased risk of Venous Thromboembolism (VTE) [1]. **Why Other Options are Incorrect:** * **Factor VI:** This factor does not exist in the modern coagulation cascade (it was previously thought to be an activated form of Factor V). * **Factor VIII:** While Factor VIII is also inactivated by Protein C, the "Leiden" mutation specifically affects Factor V. Deficiencies in Factor VIII lead to Hemophilia A. * **Factor IV:** This refers to Calcium ions ($Ca^{2+}$), which are essential cofactors for several steps in the coagulation cascade but are not associated with the Leiden mutation. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Autosomal Dominant. * **Clinical Presentation:** Recurrent Deep Vein Thrombosis (DVT) and Pulmonary Embolism [1]. * **Diagnosis:** Suspect in patients with "Activated Protein C Resistance" on screening assays; confirmed by genetic testing (PCR). * **Key Association:** It is a major risk factor for cerebral venous thrombosis in women taking oral contraceptive pills (OCPs). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 133-134.

Q: Keratinizing metaplasia of salivary glands results due to the deficiency of which vitamin?

Vitamin A. **Explanation:** **Vitamin A (Retinol)** is essential for the maintenance of specialized epithelia, particularly the differentiation of mucus-secreting columnar epithelium. When Vitamin A is deficient, these specialized cells undergo **squamous metaplasia**, transforming into a keratinizing stratified squamous epithelium [1]. This process occurs in the salivary glands, respiratory tract, and urinary tract [1]. In the salivary glands, the loss of mucus production and the buildup of keratin debris can lead to ductal obstruction and secondary infections. **Analysis of Incorrect Options:** * **Thiamine (Vitamin B1):** Deficiency primarily leads to Beriberi (Dry/Wet) and Wernicke-Korsakoff syndrome, affecting the cardiovascular and nervous systems, not epithelial differentiation. * **Riboflavin (Vitamin B2):** Deficiency is characterized by cheilosis, glossitis, and corneal neovascularization, but it does not cause keratinizing metaplasia. * **Vitamin E:** Acts as a potent antioxidant protecting cell membranes from lipid peroxidation. Deficiency leads to hemolytic anemia and neurological deficits (spinocerebellar ataxia). **NEET-PG High-Yield Pearls:** * **Metaplasia** is a reversible change where one adult cell type is replaced by another to withstand stress [1]. * **Vitamin A & the Eye:** Deficiency causes Xerophthalmia. The sequence is: Nyctalopia (Night blindness) → Conjunctival xerosis → **Bitot’s spots** (keratin plaques) → Corneal xerosis → Keratomalacia (corneal melting). * **Therapeutic use:** All-trans retinoic acid (ATRA) is used in Acute Promyelocytic Leukemia (M3) to induce cell differentiation. **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. 49.

Question 1

What is the Leiden factor?

Accepted Answer

Factor V

Answer

Factor VI

Answer

Factor VIII

Answer

Factor IV

Question 2

What is the half-life of C-reactive protein (CRP)?

Accepted Answer

20 hours

Answer

6 hours

Answer

12 hours

Answer

24 hours

Question 3

Keratinizing metaplasia of salivary glands results due to the deficiency of which vitamin?

Accepted Answer

Vitamin A

Answer

Thiamine

Answer

Riboflavin

Answer

Vitamin E

Question 4

In malignant hypertension, necrosis is of which type?

Accepted Answer

Fibrinoid necrosis

Answer

Caseous necrosis

Answer

Liquifactive necrosis

Answer

Coagulative necrosis

Question 5

NSAID drug-induced edema is primarily due to which of the following mechanisms?

Accepted Answer

Increased hydrostatic pressure

Answer

Protein-losing enteropathy

Answer

Endothelial damage due to IL-2

Answer

Low oncotic pressure

Question 6

Granulomatous inflammatory reaction is caused by all of the following EXCEPT:

Accepted Answer

Mycoplasma

Answer

M. Tuberculosis

Answer

M. Leprae

Answer

Yersinia pestis

Question 7

Malignant cells characteristically

Accepted Answer

Take at least 30 doubling times before they become clinically detectable

Answer

Have a shorter cell cycle than the normal cells in their parent tissue

Answer

Have the same DNA content as the normal cells in their parent tissue

Answer

Are contact inhibited in tissue culture

Question 8

Clear cells are commonly seen in which of the following lesions?

Accepted Answer

Mucoepidermoid carcinoma

Answer

Pleomorphic adenoma

Answer

Warthin's tumor

Answer

Adenomatoid odontogenic tumor

Question 9

What are the chances of an offspring being affected when one parent is an autosomal dominant heterozygote?

Accepted Answer

50%

Answer

25%

Answer

100%

Answer

None

Question 10

What is the term for physiologic programmed cell death?

Accepted Answer

Apoptosis

Answer

Lysis

Answer

Autolysis

Answer

Autopsy

General Pathology — MCQs

General Pathology — MCQs

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