General Pathology Practice Questions

Q: Amyloid deposits stain positively with all of the following agents except?

Methenamine silver. ### Explanation **Amyloidosis** is characterized by the extracellular deposition of misfolded proteins in a cross-beta pleated sheet conformation. Identifying these deposits requires specific histochemical stains. **Why Methenamine Silver is the Correct Answer:** **Methenamine silver (Gomori's or Grocott's)** is primarily used to visualize **fungal elements** (like *Candida* or *Pneumocystis*) and basement membranes. It is not a standard stain for amyloid. While silver stains like Bielschowsky or Thioflavin-S are used to identify amyloid plaques in Alzheimer’s disease [1], Methenamine silver specifically does not target amyloid deposits. **Analysis of Incorrect Options:** * **Congo Red:** The gold standard for amyloid. Under ordinary light, it stains amyloid pink-red. Under polarized light, it exhibits the pathognomonic **apple-green birefringence** due to the beta-pleated sheet structure. * **Crystal Violet (and Methyl Violet):** These are metachromatic stains. Amyloid reacts with these dyes to produce a **rose-pink or violet** color against a blue background. * **Thioflavin T:** A fluorescent dye that binds to the beta-sheet structure of amyloid. When viewed under a fluorescence microscope, it emits a **bright yellow-green fluorescence**. It is highly sensitive but less specific than Congo red. **NEET-PG High-Yield Pearls:** * **Most sensitive stain:** Thioflavin T (used for screening). * **Most specific/Gold standard:** Congo Red (with polarization). * **Electron Microscopy:** Shows non-branching, linear fibrils (7.5–10 nm diameter). * **H&E Stain:** Amyloid appears as an amorphous, eosinophilic, extracellular hyaline substance. * **Common Amyloid Types:** **AL** (Light chain - Plasma cell dyscrasias), **AA** (Serum Amyloid Associated - Chronic inflammation), **Aβ** (Alzheimer’s disease) [2].

Q: What is the most important cause of death in septic shock?

Cardiac failure. In septic shock, the most critical factor leading to mortality is **Cardiac Failure** (specifically, septic cardiomyopathy) [3]. While sepsis is initially characterized by high cardiac output and low systemic vascular resistance (distributive shock), the release of pro-inflammatory cytokines (like TNF-α and IL-1β) and nitric oxide leads to direct myocardial depression [2]. This results in biventricular dilatation, decreased ejection fraction, and impaired contractility. Despite adequate fluid resuscitation, the heart's inability to maintain perfusion to vital organs is the primary driver of death. **Analysis of Incorrect Options:** * **Renal Failure (A):** Acute Kidney Injury (AKI) is a very common complication of sepsis due to hypoperfusion and inflammation, but it is rarely the immediate cause of death due to the availability of Renal Replacement Therapy (dialysis). * **Respiratory Failure (C):** While many patients develop ARDS (Acute Respiratory Distress Syndrome), modern mechanical ventilation strategies have significantly reduced it as the primary cause of mortality compared to circulatory collapse. * **DIC (D):** Disseminated Intravascular Coagulation is a severe hematological complication that leads to microvascular thrombosis and bleeding, but it is usually a secondary manifestation of the systemic inflammatory response rather than the terminal event [1]. **NEET-PG High-Yield Pearls:** * **Septic Cardiomyopathy:** Characterized by reversible systolic and diastolic dysfunction. * **Hemodynamic Hallmark:** Decreased Systemic Vascular Resistance (SVR) and increased Cardiac Output (initially). * **Early Goal-Directed Therapy (EGDT):** Focuses on maintaining Mean Arterial Pressure (MAP) >70 mmHg to prevent multi-organ failure [4]. * **Drug of Choice:** Norepinephrine is the first-line vasopressor for septic shock.

Q: A 40-year-old female patient in her third trimester of pregnancy complains of bilateral leg swelling. Which type of thrombosis is most likely to be present in this patient?

Venous. **Explanation:** The correct answer is **Venous (Option A)**. Pregnancy is a well-known **hypercoagulable state** due to Virchow’s Triad: 1. **Stasis:** The gravid uterus compresses the inferior vena cava and iliac veins, leading to venous stasis in the lower extremities (presenting as bilateral leg swelling). 2. **Endothelial Injury:** Occurs during delivery or through vascular remodeling. 3. **Hypercoagulability:** There is a physiological increase in clotting factors (I, VII, VIII, IX, X) and a decrease in natural anticoagulants like Protein S. **Why other options are incorrect:** * **Arterial (Option B):** While arterial thrombosis can occur (e.g., stroke or MI), it is significantly less common than venous thromboembolism (VTE) in pregnancy. Arterial clots usually require pre-existing atherosclerosis or severe endothelial damage. * **Mural (Option C):** These are thrombi that adhere to the wall of a cardiac chamber or the aorta. They are typically associated with myocardial infarction or atrial fibrillation, not pregnancy-induced stasis. * **Saddle (Option D):** A saddle embolus is a large blood clot that straddles the bifurcation of the pulmonary artery. While it is a life-threatening complication of a Deep Vein Thrombosis (DVT), the *primary* type of thrombosis occurring in the legs is venous. **NEET-PG High-Yield Pearls:** * **Risk:** The risk of VTE is 4–5 times higher in pregnant women compared to non-pregnant women. * **Localization:** Pregnancy-related DVT occurs more frequently in the **left leg** (approx. 80-90%) due to the compression of the left common iliac vein by the right common iliac artery (**May-Thurner anatomy**). * **Most common period:** The highest risk for VTE is actually the **postpartum period** (puerperium).

Q: Which of the following is a useful marker to detect autophagy in cells?

LC3. **Explanation:** **Autophagy** is a process of "self-eating" where cells sequester cytoplasmic organelles and proteins into double-membrane vesicles called **autophagosomes**, which then fuse with lysosomes for degradation [1]. **Why LC3 is the correct answer:** **LC3 (Microtubule-associated protein 1 Light Chain 3)** is the most widely used marker for autophagy. During the initiation of autophagy, the cytosolic form (LC3-I) is conjugated with phosphatidylethanolamine to form **LC3-II**. This lipidated form (LC3-II) specifically binds to the autophagosomal membrane. Therefore, the presence and accumulation of LC3-II (detected via western blot or immunofluorescence as "puncta") serve as a definitive marker for the formation of autophagosomes. **Why the other options are incorrect:** * **BAK and BAX (Options A & B):** These are **pro-apoptotic** members of the Bcl-2 family. They act as "molecular sensors" that form pores in the outer mitochondrial membrane, leading to the release of Cytochrome C and the initiation of the intrinsic pathway of apoptosis. * **BID (Option D):** This is a "BH3-only" pro-apoptotic protein. It acts as a link between the extrinsic and intrinsic pathways; when cleaved by Caspase-8 into **t-BID**, it activates BAX/BAK. **High-Yield NEET-PG Pearls:** * **Atg genes:** Autophagy-related genes (Atg) regulate the various stages of this process [1]. * **p62 (Sequestosome 1):** Another marker for autophagy; it binds to cargo and LC3. Unlike LC3, p62 levels **decrease** when autophagy is complete (as it is degraded). * **Clinical Link:** Autophagy is implicated in neurodegenerative diseases (Alzheimer’s), cancer (both as a suppressor and a survival mechanism), and defense against intracellular pathogens (Mycobacteria). **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. 71-73.

Question 1

Which of the following is NOT a component of Virchow's triad?

Accepted Answer

Abnormalities of venous channels

Answer

Stasis of blood

Answer

Hypercoagulability

Answer

Endothelial damage

Question 2

Dystrophic calcification occurs in all of the following conditions except?

Accepted Answer

Normal kidney

Answer

Rheumatic heart disease

Answer

Lymph node

Answer

Aneurysm

Question 3

What ultrastructural finding is characteristic of irreversible cellular injury?

Accepted Answer

Amorphous densities in mitochondria

Answer

Ribosomal detachment from the endoplasmic reticulum

Answer

Formation of phagolysosomes

Answer

Cell swelling

Question 4

In an experiment, metabolically active cells are subjected to radiant energy in the form of x-rays. This results in cell injury caused by hydrolysis of water. Which of the following intracellular enzymes helps to protect the cells from this type of injury?

Accepted Answer

Glutathione peroxidase

Answer

Endonuclease

Answer

Lactate dehydrogenase

Answer

Phospholipase

Question 5

Amyloid deposits stain positively with all of the following agents except?

Accepted Answer

Methenamine silver

Answer

Congo red

Answer

Crystal violet

Answer

Thioflavin T

Question 6

Which of the following is NOT a mutation associated with Down syndrome?

Accepted Answer

VNTRs

Answer

Mosaicism

Answer

Robertsonian translocation

Answer

Maternal nondisjunction

Question 7

What is the most important cause of death in septic shock?

Accepted Answer

Cardiac failure

Answer

Renal failure

Answer

Respiratory failure

Answer

Disseminated Intravascular Coagulation (DIC)

Question 8

Which of the following organs does not typically show a pale infarct?

Accepted Answer

Lung

Answer

Heart

Answer

Kidney

Answer

Spleen

Question 9

A 40-year-old female patient in her third trimester of pregnancy complains of bilateral leg swelling. Which type of thrombosis is most likely to be present in this patient?

Accepted Answer

Venous

Answer

Arterial

Answer

Mural

Answer

Saddle

Question 10

Which of the following is a useful marker to detect autophagy in cells?

Accepted Answer

LC3

Answer

BAK

Answer

BAX

Answer

BID

General Pathology — MCQs

General Pathology — MCQs

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