General Pathology Practice Questions

Q: Iron in tissues is stained with which of the following stains?

Prussian Blue. **Explanation:** **Prussian Blue (Perls' Stain)** is the correct answer because it is the gold-standard histochemical stain used to detect **ferric iron (Fe³⁺)** in tissues [1]. The underlying chemical principle involves the reaction of ferric iron with potassium ferrocyanide in an acidic medium, resulting in the formation of a bright blue pigment called ferric ferrocyanide (Prussian Blue). This stain is primarily used to visualize iron stored in the form of **hemosiderin** within macrophages (siderophages) or parenchymal cells [1]. **Analysis of Incorrect Options:** * **Sudan O (Sudan III/IV):** These are lipid-soluble dyes used to stain **neutral fats (lipids)** and triglycerides. They are commonly used on frozen sections to diagnose fat embolism or steatosis. * **PAS (Periodic Acid-Schiff):** This stain detects **glycogen** and mucopolysaccharides. It is widely used to visualize basement membranes, fungal walls, and glycogen storage diseases. **Clinical Pearls for NEET-PG:** * **Hemochromatosis vs. Hemosiderosis:** Prussian Blue is essential for grading iron overload in the liver and heart [1]. * **Sideroblastic Anemia:** This stain identifies "Ringed Sideroblasts" in the bone marrow (iron-laden mitochondria surrounding the nucleus). * **Heart Failure Cells:** In chronic passive congestion of the lungs, Prussian Blue identifies hemosiderin-laden macrophages in the alveoli. * **Note:** It does **not** stain iron in hemoglobin or ferritin directly; it specifically targets the insoluble hemosiderin. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 854-855.

Q: A ring chromosome is a result of which chromosomal abnormality?

Deletion. **Explanation:** A **ring chromosome** is a structural chromosomal abnormality that occurs when a chromosome undergoes **terminal deletions** at both the short (p) and long (q) arms. Following the loss of these distal segments, the remaining "sticky" ends of the central portion fuse together to form a ring shape. Because the formation of a ring chromosome necessitates the loss of genetic material from the telomeric regions, it is fundamentally a result of **deletion**. **Analysis of Options:** * **A. Deletion (Correct):** As described, the breakage of both ends of a chromosome followed by fusion is the mechanism. The resulting loss of genetic material often leads to clinical phenotypes (e.g., Ring 20 syndrome). * **B. Inversion:** This involves a single chromosome undergoing two breaks, with the intervening segment rotating 180° and reinserting. There is no loss of genetic material (balanced). * **C. Duplication:** This refers to the presence of an extra copy of a segment of a chromosome. * **D. Translocation:** This involves the exchange of segments between non-homologous chromosomes (e.g., Robertsonian or Reciprocal translocations). **High-Yield NEET-PG Pearls:** * **Karyotype Notation:** A ring chromosome is denoted by the symbol **'r'** (e.g., 46,XX,r(15)). * **Clinical Significance:** Ring chromosomes are often unstable during mitosis, leading to mosaicism [2]. * **Common Example:** **Ring 14 syndrome** (characterized by seizures and intellectual disability) and **Ring X** (a variant of Turner Syndrome) [1]. * **Telomeres:** Normally, telomeres prevent end-to-end fusion; ring formation only occurs when telomeres are lost via deletion. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 175-177. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 168-169.

Q: What is the chromosomal karyotype in Patau syndrome?

47XX,+13. **Explanation:** **Patau Syndrome** is a chromosomal disorder caused by **Trisomy 13** [1]. In a normal human karyotype, there are 46 chromosomes (23 pairs). In Patau syndrome, there is an extra copy of chromosome 13, resulting in a total of 47 chromosomes. The correct karyotype for a female with this condition is **47,XX,+13** [1]. **Analysis of Options:** * **Option A (47,XX,+21):** This represents Trisomy 21, which is **Down Syndrome**, the most common autosomal trisomy [1]. * **Option B (46,XX/47,XX,+18):** This represents a **mosaicism** for Trisomy 18 (**Edwards Syndrome**) [1]. While Edwards syndrome is Trisomy 18, the question asks specifically for Patau syndrome. * **Option C (45,XX,der(14;21)):** This describes a **Robertsonian Translocation** involving chromosomes 14 and 21. This individual is a balanced carrier and is phenotypically normal but at high risk of having children with Down Syndrome [1]. **High-Yield Clinical Pearls for NEET-PG:** To differentiate the three major trisomies, remember the "Ages of Trisomy": 1. **Trisomy 13 (Patau):** Think "P" for **P**uberty (age 13). Key features: **P**olydactyly, **P**unched-out scalp lesions (Aplasia cutis), **P**alate (Cleft lip/palate), and Holoprosencephaly. 2. **Trisomy 18 (Edwards):** Think "E" for **E**lection (age 18). Key features: **E**minent occiput, **E**lfin ears, Rocker-bottom feet, and Clenched fists (overlapping fingers). 3. **Trisomy 21 (Down):** Think "D" for **D**rinking (age 21). Key features: Simian crease, Brushfield spots, and early-onset Alzheimer’s. *Note: Patau syndrome has the worst prognosis among the three, with most infants not surviving past the first year of life.* [1] **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 171-172.

Question 1

Which of the following conditions is associated with PAS-positive macrophages?

Accepted Answer

Whipple's disease

Answer

Tropical sprue

Answer

Celiac disease

Answer

Crohn's disease

Question 2

Iron in tissues is stained with which of the following stains?

Accepted Answer

Prussian Blue

Answer

Sudan O

Answer

PAS

Answer

None of the above

Question 3

Cat eye syndrome is associated with which chromosomal abnormality?

Accepted Answer

Trisomy 22

Answer

Trisomy 21

Answer

Trisomy 18

Answer

Trisomy 13

Question 4

Free radical injury includes all except?

Accepted Answer

Vacuolar degeneration

Answer

Damaged cell membranes

Answer

Loss of enzymatic activity

Answer

Single strand break of DNA

Question 5

The action of putrefactive bacteria on necrotic tissue results in what?

Accepted Answer

Gangrene

Answer

Infarction

Answer

Embolism

Answer

Coagulation

Question 6

A ring chromosome is a result of which chromosomal abnormality?

Accepted Answer

Deletion

Answer

Inversion

Answer

Duplication

Answer

Translocation

Question 7

NK cells express which of the following markers?

Accepted Answer

CD16, CD56

Answer

CD 15, CD 55

Answer

CD 16, CD 57

Answer

CD21, CD 66

Question 8

What is the mode of inheritance for Huntington's chorea?

Accepted Answer

Autosomal dominant

Answer

Autosomal recessive

Answer

X-linked recessive

Answer

X-linked dominant

Question 9

What is the chromosomal karyotype in Patau syndrome?

Accepted Answer

47XX,+13

Answer

47XX,+21

Answer

46XX/47XX,+18

Answer

45XX,der(14;21)

Question 10

Which disease has autosomal recessive inheritance?

Accepted Answer

Cystic fibrosis

Answer

Hydrocephalus

Answer

Duchene muscular dystrophy

Answer

Vitamin D resistant rickets

General Pathology — MCQs

General Pathology — MCQs

On this page

Practice by Chapter

Want unlimited practice?