Cardiac Pathology Practice Questions

Q: Mac Callum plaques in rheumatic heart disease are associated with which chamber?

Left atrium. **Explanation:** **MacCallum plaques** are a classic pathological feature of **Rheumatic Heart Disease (RHD)**. They represent irregular, map-like areas of subendocardial thickening caused by the healing of inflammatory lesions (Aschoff bodies) [1]. **Why the Left Atrium is correct:** These plaques are most commonly found in the **posterior wall of the left atrium**, typically just above the posterior leaflet of the mitral valve. Their formation is attributed to the "jet effect" of chronic mitral regurgitation. The high-pressure regurgitant blood flow from the left ventricle strikes the endocardial surface of the left atrium, leading to chronic irritation, inflammation, and subsequent subendocardial fibrosis. **Why other options are incorrect:** * **Left Ventricle:** While RHD affects the mitral and aortic valves, the specific subendocardial thickening known as MacCallum plaques is not a characteristic feature of the ventricular walls. * **Right Atrium & Right Ventricle:** RHD primarily affects the high-pressure left side of the heart [1]. The right-sided chambers are rarely involved in the primary inflammatory process unless there is severe, multi-valvular disease or secondary changes due to pulmonary hypertension. **High-Yield Pearls for NEET-PG:** * **Location:** Posterior wall of the Left Atrium (above the mitral valve). * **Pathogenesis:** Result of regurgitant jets (Mitral Regurgitation) [1]. * **Microscopic Hallmark of RHD:** **Aschoff bodies** (containing Anitschkow cells or "caterpillar cells") [1]. * **Valve Involvement Frequency:** Mitral > Aortic > Tricuspid > Pulmonary (MATP) [1]. * **Bread and Butter Appearance:** Refers to the fibrinous pericarditis seen in acute rheumatic carditis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, p. 566.

Q: What is the earliest time after myocardial infarction when triphenyl tetrazolium chloride (TTC) staining can detect infarcted tissue?

3 hours. ***3 hours***- **TTC (Triphenyl Tetrazolium Chloride)** staining detects viable myocardium by reacting with **lactate dehydrogenase** (LDH) and other mitochondrial dehydrogenases, resulting in a **brick-red color** [1].- Necrotic myocardium loses these enzymes, preventing the color change and leaving the infarcted tissue **pale yellow**; this process usually takes at least **3 hours** post-occlusion to be grossly detectable [1].*1 hour*- The time interval is too short for the complete depletion of **dehydrogenases** from the infarcted cells necessary to prevent the TTC reaction and produce a visually distinct **pale area**.- Reliable gross detection by TTC requires cellular necrosis advanced enough to cause enzyme leakage, which typically requires more time than 1 hour [1].*30 minutes*- At 30 minutes post-MI, myocardial damage is often still in the stage of **reversible injury**, and the cell membranes and internal enzyme systems are still largely intact [2].- This limited timeframe does not allow for sufficient enzyme leakage or inactivation required to produce a clear negative (unstained) reaction with the **tetrazolium salt** [1].*Immediately*- Immediate staining will show uniformly red tissue because sufficient time has not passed for the irreversible cell injury (**necrosis**) and subsequent loss of intrinsic **enzymatic activity**.- Myocardium must undergo several hours of severe ischemia and necrosis before the gross chemical findings detected by **TTC** become apparent [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 552-554. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, p. 552.

Q: A 65-year-old man dies due to myocardial infarction. Which stains can be used to see the infarct in the heart while conducting an autopsy?

Triphenyl tetrazolium chloride. ***Triphenyl tetrazolium chloride***- This stain is used to macroscopically identify **acute myocardial infarction** during autopsy, typically within the first few hours up to 2 weeks post-infarct [1].- It detects the activity of **dehydrogenase enzymes** (like LDH); viable myocardium reacts with TTC to form a **brick red** color, while the necrotic (infarcted) tissue lacks these enzymes and remains **pale** or *gray-yellow* [1].*Oil red O*- **Oil red O** is a lipid stain primarily used to demonstrate neutral lipids and **triglycerides**, often used for conditions like steatosis or fat emboli.- It is not specific for the cellular necrosis defining an acute infarct and is generally used on frozen sections.*Sudan black B*- **Sudan black B** is a lipid stain used to visualize phospholipids, neutral lipids, and lipoproteins.- It is more commonly employed in hematopathology (e.g., staining **myeloblasts**) or for demonstrating specific lipid storage, not for defining the boundaries of an acute myocardial infarct in gross pathology examination.*Masson trichrome*- This is a differential stain used to distinguish between muscle (red) and **collagen** (blue or green), used to highlight **fibrosis**.- While crucial for identifying **old, healed myocardial infarcts** (scar tissue), it is ineffective for rapid visualization of a fresh, acute infarct where significant collagen deposition has not yet taken place [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 552-554.

Q: An athlete collapsed suddenly during exercise and died on the field. Postmortem heart is shown in the figure. There is family history of heart disease. What is the diagnosis?

Hypertrophic cardiomyopathy. ***Hypertrophic cardiomyopathy*** - **Sudden cardiac death** in young athletes, especially with a family history, is a classic presentation of **hypertrophic cardiomyopathy (HCM)** [2][3]. - Postmortem examination typically reveals **asymmetric septal hypertrophy** and **myocardial fiber disarray**, which are characteristic of HCM [1]. *Mitral regurgitation* - While mitral regurgitation can lead to heart failure, it is less commonly associated with **sudden death in athletes** without prior symptoms. - The primary finding would be **valvular abnormalities** and **left atrial/ventricular dilation**, not typically isolated hypertrophy. *Mitral stenosis* - Mitral stenosis primarily causes **left atrial enlargement** and **pulmonary hypertension**, leading to symptoms like dyspnea and fatigue. - It is not a common cause of **sudden cardiac death** in athletes and would not typically present with the gross hypertrophy seen in HCM. *Aortic stenosis with left ventricular hypertrophy* - Aortic stenosis can cause **left ventricular hypertrophy** due to increased pressure overload. - However, sudden death in athletes due to aortic stenosis is less common than HCM, and the hypertrophy in aortic stenosis is typically **concentric** and symmetrical, unlike the asymmetric hypertrophy often seen in HCM [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 577-578. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 576-577. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Cardiovascular Disease, pp. 303-304.

Q: All are true regarding the heart specimen shown except:

Spade-shaped cavity of left ventricle. ***Spade-shaped cavity of left ventricle*** - The heart specimen in **hypertrophic cardiomyopathy (HCM)** typically shows a **banana-shaped or crescentic left ventricular cavity** due to the hypertrophied septum bulging into the outflow tract [1]. - A **spade-shaped cavity** is characteristic of **apical hypertrophic cardiomyopathy**, which is a specific, less common variant of HCM. *Asymmetrical septal hypertrophy* - This is a hallmark feature of **hypertrophic cardiomyopathy (HCM)**, where the **interventricular septum** is disproportionately thicker than the free wall of the left ventricle [1][2]. - It is the most common morphological pattern seen in HCM [2]. *Left ventricular outflow tract obstruction* - This occurs in a significant proportion of HCM patients due to the **hypertrophied septum** and **systolic anterior motion (SAM)** of the mitral valve [1]. - The obstruction leads to a **pressure gradient** across the left ventricular outflow tract, causing symptoms like dyspnea and syncope [1]. *Diastolic dysfunction* - **Diastolic dysfunction** is a universal finding in HCM due to the **stiff, non-compliant hypertrophied left ventricle** [1]. - This impaired relaxation and filling of the ventricle leads to elevated **diastolic pressures** and contributes to symptoms of heart failure [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 577-578. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Cardiovascular Disease, pp. 303-304.

Q: A patient presented with mitral valve stenosis, identify the diagnosis from the mitral valve histopathology depicted below. (AIIMS Nov 2017)

Rheumatic heart disease. ***Rheumatic heart disease*** - **Rheumatic heart disease** is the most common cause of **mitral valve stenosis** and is characterized by **fibrosis** and **calcification** of the valve leaflets, often with **commissural fusion** [1]. - Histopathology would show features like **Aschoff bodies** (granulomas with Anitschkow cells) in the acute phase [3], and later **fibrous thickening** and **neovascularization** of the valve [1]. *Tuberculosis* - While tuberculosis can affect the heart (tuberculous pericarditis or myocarditis), it is an **extremely rare cause of isolated valvular stenosis**. - Histopathology would show **caseating granulomas** with **Langhans giant cells**, which are not typical findings in primary valvular stenosis. *Myxomatous degeneration* - **Myxomatous degeneration** primarily affects the **mitral valve**, leading to **mitral valve prolapse** and **regurgitation**, not stenosis. - Histopathology shows **accumulation of proteoglycans** and **disruption of collagen fibers** within the valve, making it floppy. *Viral myocarditis* - **Viral myocarditis** is an inflammation of the **myocardium** (heart muscle) and typically leads to **dilated cardiomyopathy** and **heart failure**, not primary valvular stenosis. - Histopathology would reveal **inflammatory infiltrates** (lymphocytes) and **myocyte necrosis**, not changes specific to valve stenosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 566-567. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Cardiovascular Disease, pp. 293-294. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, p. 566.

Question 1

What is the most common cause of death in primary amyloidosis?

Accepted Answer

Cardiac failure

Answer

Respiratory failure

Answer

Renal failure

Answer

Septicemia

Question 2

Which of the following can cause myocarditis?

Accepted Answer

Pertussis

Answer

Measles

Answer

Diphtheria

Answer

Scorpion sting

Question 3

Mac Callum plaques in rheumatic heart disease are associated with which chamber?

Accepted Answer

Left atrium

Answer

Left ventricle

Answer

Right atrium

Answer

Right ventricle

Question 4

Which is the first organ to be affected in left ventricular failure?

Accepted Answer

Lungs

Answer

Liver

Answer

Kidney

Answer

Brain

Question 5

What are the causes of restrictive cardiomyopathy?

Accepted Answer

All of the above

Answer

Amyloidosis

Answer

Sarcoidosis

Answer

Storage disease

Question 6

What is the earliest time after myocardial infarction when triphenyl tetrazolium chloride (TTC) staining can detect infarcted tissue?

Accepted Answer

3 hours

Answer

1 hour

Answer

30 minutes

Answer

Immediately

Question 7

A 65-year-old man dies due to myocardial infarction. Which stains can be used to see the infarct in the heart while conducting an autopsy?

Accepted Answer

Triphenyl tetrazolium chloride

Answer

Oil red O

Answer

Sudan black B

Answer

Masson trichrome

Question 8

An athlete collapsed suddenly during exercise and died on the field. Postmortem heart is shown in the figure. There is family history of heart disease. What is the diagnosis?

Accepted Answer

Hypertrophic cardiomyopathy

Answer

Mitral regurgitation

Answer

Mitral stenosis

Answer

Aortic stenosis with left ventricular hypertrophy

Question 9

All are true regarding the heart specimen shown except:

Accepted Answer

Spade-shaped cavity of left ventricle

Answer

Asymmetrical septal hypertrophy

Answer

Left ventricular outflow tract obstruction

Answer

Diastolic dysfunction

Question 10

A patient presented with mitral valve stenosis, identify the diagnosis from the mitral valve histopathology depicted below. (AIIMS Nov 2017)

Accepted Answer

Rheumatic heart disease

Answer

Tuberculosis

Answer

Myxomatous degeneration

Answer

Viral myocarditis

Cardiac Pathology — MCQs

Cardiac Pathology — MCQs

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