General Pathology US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for General Pathology. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
General Pathology US Medical PG Question 1: A 52-year-old man is brought to the emergency department by ambulance after a motor vehicle accident. He was an unrestrained passenger who was ejected from the vehicle. On presentation, he is found to be actively bleeding from numerous wounds. His blood pressure is 76/42 mmHg and pulse is 152/min. Attempts at resuscitation fail, and he dies 25 minutes later. Autopsy shows blood in the peritoneal cavity, and histology of the kidney reveals swelling of the proximal convoluted tubule epithelial cells. Which of the following is most likely the mechanism underlying the renal cell findings?
- A. Decreased activity of caspase 7
- B. Increased activity of caspase 9
- C. Increased function of the Na+/K+-ATPase
- D. Increased activity of caspase 8
- E. Decreased function of the Na+/K+-ATPase (Correct Answer)
General Pathology Explanation: ***Decreased function of the Na+/K+-ATPase***
- The patient experienced **hypovolemic shock** due to severe blood loss, leading to a significant drop in blood pressure and organ perfusion. This results in **ischemia** of the renal cells.
- **Ischemic injury** impairs ATP production, which is essential for the function of the **Na+/K+-ATPase pump**. Failure of this pump leads to intracellular accumulation of sodium and water, causing **cellular swelling**, particularly noticeable in the proximal convoluted tubules.
*Decreased activity of caspase 7*
- **Caspases**, including caspase 7, are involved in **apoptosis** (programmed cell death), which involves cell shrinkage and fragmentation, not the swelling observed here.
- Decreased caspase activity would generally *reduce* apoptosis, which is not the primary mechanism of acute cell injury in shock.
*Increased activity of caspase 9*
- Increased activity of **caspase 9** is indicative of the **intrinsic apoptotic pathway**, typically initiated by mitochondrial damage.
- While prolonged ischemia can eventually lead to apoptotic changes, the acute finding of **cellular swelling** points more directly to immediate membrane pump dysfunction due to ATP depletion.
*Increased function of the Na+/K+-ATPase*
- **Increased function** of the Na+/K+-ATPase would actively pump sodium out of the cell and potassium in, *preventing* intracellular swelling.
- This option contradicts the observed finding of proximal convoluted tubule epithelial cell swelling, which is characteristic of acute cellular injury due to pump failure.
*Increased activity of caspase 8*
- **Caspase 8** is a key initiator caspase in the **extrinsic apoptotic pathway**, often triggered by death receptor signaling.
- Similar to caspase 9, increased caspase 8 activity would lead to apoptosis, characterized by cell shrinkage, not the **cellular swelling** seen in acute ischemic injury.
General Pathology US Medical PG Question 2: A 78-year-old man with a history of myocardial infarction status post coronary artery bypass grafting and a 60-pack-year history of smoking is found deceased in his apartment after not returning calls to his family for the last 2 days. The man was last known to be alive 3 days ago, when his neighbor saw him getting his mail. The family requests an autopsy. On autopsy, the man is found to have a 100% blockage of his left anterior descending artery of his heart and likely passed from sudden cardiac death 2 days prior. Which of the following findings is expected to be found on histologic examination of his damaged myocardium?
- A. Fat saponification
- B. Cellular debris and lymphocytes
- C. Cystic cavitation
- D. Cellular debris and macrophages
- E. Uniform binding of acidophilic dyes (Correct Answer)
General Pathology Explanation: ***Uniform binding of acidophilic dyes***
- This finding, often described as **coagulative necrosis**, is characteristic of myocardial infarction 1-3 days after onset, as enzymes denature and bind to eosin more uniformly.
- The patient was found deceased 2 days after his suspected death, placing the myocardial changes within this timeframe.
*Fat saponification*
- **Fat saponification** is a type of fat necrosis, typically seen in the pancreas or breast, resulting from the enzymatic destruction of fat cells.
- It does not occur in the myocardium following an ischemic event.
*Cellular debris and lymphocytes*
- **Lymphocytes** are generally not the predominant inflammatory cells in the initial stages of a myocardial infarction.
- While cellular debris would be present, the primary inflammatory infiltrate in the first 3 days after an MI is typically **neutrophils**, not lymphocytes.
*Cystic cavitation*
- **Cystic cavitation** is a characteristic feature of liquefactive necrosis, which occurs in the brain following an ischemic stroke, but not in the heart.
- The heart undergoes **coagulative necrosis** after an MI.
*Cellular debris and macrophages*
- **Macrophages** become prominent later in the healing process of a myocardial infarction, typically starting around **3-7 days** after the event.
- At the 2-day mark, the dominant cells would still be neutrophils and necrotic myocytes.
General Pathology US Medical PG Question 3: A 68-year-old man presents to his primary care provider after noticing that his urine has been pink for the last week. He does not have any pain with urination, nor has he had any associated fevers or infections. On his review of systems, the patient notes that he thinks he has lost some weight since his belt is looser, and he has also had occasional dull pressure in his back for the past two months. His temperature is 98.8°F (37.1°C), blood pressure is 132/90 mmHg, pulse is 64/min, and respirations are 12/min. The patient weighs 210 lbs (95.3 kg, BMI 31.9 kg/m²), compared to his weight of 228 lbs (103.4 kg, BMI 34.7 kg/m²) at his last visit 2 years prior. On exam, the patient does not have any back or costovertebral angle tenderness. On abdominal palpation, a firm mass can be appreciated deep in the left abdomen. Given the suspected diagnosis, the clinical workup should also assess for which of the following paraneoplastic syndromes?
- A. Hypercalcemia (Correct Answer)
- B. Polycythemia
- C. Anemia
- D. Stauffer syndrome
- E. Hypercortisolism
General Pathology Explanation: ***Hypercalcemia***
- The patient's presentation with **painless hematuria**, unexplained weight loss, flank pain, and a palpable abdominal mass is highly suggestive of **renal cell carcinoma (RCC)**.
- **Hypercalcemia** is the **most common paraneoplastic syndrome** associated with RCC, occurring in 10-20% of cases, often due to the tumor secreting **parathyroid hormone-related protein (PTHrP)**.
- This is the most important metabolic abnormality to screen for in the initial workup.
*Polycythemia*
- While **polycythemia** can be a paraneoplastic syndrome in RCC due to **erythropoietin (EPO) production**, it occurs in only 3-10% of cases, making it less common than hypercalcemia.
- The patient's symptoms do not specifically point to an excess red blood cell count.
*Anemia*
- **Anemia** is actually the most common hematologic finding in RCC (20-40% of cases), more common than polycythemia.
- It represents a paraneoplastic effect related to chronic disease and inflammatory cytokines.
- However, **hypercalcemia is the more critical paraneoplastic syndrome to assess** given its prognostic significance and need for intervention.
*Stauffer syndrome*
- **Stauffer syndrome** is a paraneoplastic syndrome associated with RCC characterized by **non-metastatic hepatic dysfunction** with elevated alkaline phosphatase and prolonged prothrombin time.
- While it occurs in 3-20% of cases, **hypercalcemia is more common** and typically assessed first in the metabolic workup.
*Hypercortisolism*
- **Hypercortisolism (Cushing's syndrome)** is rarely associated with RCC; it is more typically seen with **small cell lung carcinoma** or **adrenal tumors** producing ectopic ACTH.
- There are no symptoms mentioned in the patient's presentation to suggest excess cortisol production.
General Pathology US Medical PG Question 4: Researchers are investigating the mechanism of cell apoptosis and host defense in mice. They have observed that mice with certain gene deletions are not able to fight the induced viral infection. They identify a cell that is able to destroy target cells infected with viruses by exocytosis of granule contents, which induces the activation of caspases. Which type of cell is responsible for this process?
- A. CD8+ lymphocytes (Correct Answer)
- B. CD4+ lymphocytes
- C. Macrophages
- D. Neutrophils
- E. Eosinophils
General Pathology Explanation: ***CD8+ lymphocytes***
- **CD8+ lymphocytes**, or **cytotoxic T lymphocytes (CTLs)**, are specialized to recognize and kill **virus-infected cells** and cancer cells.
- They achieve this by releasing cytotoxic granules containing **perforin** and **granzymes**, which enter the target cell and activate **caspases**, leading to **apoptosis**.
- Note: **Natural killer (NK) cells** also use a similar granule-mediated mechanism, but CD8+ T cells provide **antigen-specific** recognition via MHC class I.
*CD4+ lymphocytes*
- **CD4+ lymphocytes**, or **helper T cells**, primarily coordinate immune responses by secreting **cytokines** and activating other immune cells, rather than directly killing infected cells.
- They are crucial for both humoral and cell-mediated immunity but do not typically induce apoptosis via granule exocytosis.
*Macrophages*
- **Macrophages** are phagocytic cells that engulf and digest pathogens, cellular debris, and foreign substances.
- While they can present antigens and participate in immune responses, their primary role in antiviral defense is **phagocytosing infected cells** and presenting antigens, not inducing apoptosis via granule exocytosis.
*Neutrophils*
- **Neutrophils** are key components of the innate immune system, primarily involved in fighting bacterial infections through **phagocytosis**, degranulation, and formation of **neutrophil extracellular traps (NETs)**.
- They are not specialized for detecting and inducing apoptosis in virus-infected cells.
*Eosinophils*
- **Eosinophils** are primarily involved in the immune response against **parasitic infections** and allergic reactions.
- They release granules containing toxic proteins against parasites and contribute to inflammation, but they do not directly kill virus-infected cells via caspase activation.
General Pathology US Medical PG Question 5: A 19-year-old woman presents to her primary care physician because she has been feeling increasingly lethargic over the last 6 months. Specifically, she says that she feels tired easily and has been cold even though she is wearing lots of layers. Her medical history is significant for seasonal allergies but is otherwise unremarkable. When prompted, she also says that she has a hard time swallowing food though she has no difficulty drinking liquids. Physical exam reveals a midline mass in her neck. Which of the following structures would most likely be seen if this patient's mass was biopsied?
- A. Lymphatic ducts
- B. Neutrophilic invasion
- C. Blood vessels
- D. Follicles with colloid (Correct Answer)
- E. Hollow epithelial duct
General Pathology Explanation: ***Follicles with colloid***
- The patient's symptoms (lethargy, cold intolerance, difficulty swallowing solids, midline neck mass) are highly suggestive of **hypothyroidism** due to a **goiter**, which often arises from an enlarged thyroid gland.
- The **thyroid gland** is composed of follicles filled with **colloid**, which is the storage form of thyroid hormones. A biopsy of an enlarged thyroid gland would therefore show these structures.
*Lymphatic ducts*
- **Lymphatic ducts** are part of the lymphatic system, which is involved in immune function and fluid balance, not typically found in a thyroid biopsy under these circumstances.
- While neck masses can sometimes be enlarged lymph nodes, the symptoms point specifically to thyroid dysfunction rather than a lymphatic issue.
*Neutrophilic invasion*
- **Neutrophilic invasion** indicates an acute inflammatory or infectious process, which is not suggested by the chronic and systemic symptoms presented here.
- This finding would be more typical of an abscess or acute thyroiditis, which usually presents with pain and fever.
*Blood vessels*
- While **blood vessels** are present in all tissues, including the thyroid, they are not the *most characteristic* or defining structure seen during a biopsy of a mass suspected to be an enlarged thyroid gland.
- The question asks for the structure *most likely* to be seen, implying a unique and diagnostic histological feature.
*Hollow epithelial duct*
- **Hollow epithelial ducts** are characteristic of structures like salivary glands or cysts formed from developmental remnants (e.g., thyroglossal duct cyst), but less likely to be the primary finding in an enlarged thyroid gland causing systemic symptoms of hypothyroidism.
- A thyroglossal duct cyst would typically present as a midline neck mass that moves with tongue protrusion, and while it could cause dysphagia, it typically doesn't cause symptoms of hypothyroidism.
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