A 14-year-old Caucasian female with a family history of familial hypercholesterolemia commits suicide by drug overdose. Her family decides to donate her organs, and her heart is removed for donation. After removing the heart, the cardiothoracic surgeon notices flat yellow spots on the inside of her aorta. Which of the following cell types predominate in these yellow spots?
Q2
A 51-year-old man comes to the physician for the evaluation of a 3-week history of fatigue and shortness of breath. One year ago, a screening colonoscopy showed colonic polyps. His brother has a bicuspid aortic valve. On examination, a late systolic crescendo-decrescendo murmur is heard at the right upper sternal border. Laboratory studies show:
Hemoglobin 9.1 g/dL
LDH 220 U/L
Haptoglobin 25 mg/dL (N = 41–165 mg/dL)
Urea nitrogen 22 mg/dL
Creatinine 1.1 mg/dL
Total bilirubin 1.8 mg/dL
A peripheral blood smear shows schistocytes. Which of the following is the most likely cause of this patient's anemia?
Q3
A 38-year-old man comes to the physician because of a 3-week history of a painful rash affecting his left foot. For the past 2 years, he has had recurrent episodes of color changes in his fingers when exposed to the cold; his fingers first turn white and then progress to blue and red before spontaneously resolving. He has smoked two packs of cigarettes daily for 20 years. His blood pressure is 115/78 mm Hg. Physical examination shows multiple tender, dark purple nodules on the lateral surface of the left foot with surrounding erythema that follow the course of the lateral marginal vein. There are dry ulcers on the tip of his right index finger and on the distal aspect of his right hallux. Serum lipid studies show no abnormalities. Biopsy of the dorsalis pedis artery will most likely show which of the following findings?
Q4
A 73-year-old man with coronary artery disease and hypertension is brought to the emergency department by ambulance 90 minutes after the acute onset of substernal chest pain and dyspnea. He has smoked 2 packs of cigarettes daily for 52 years. Shortly after arriving at the hospital, he loses consciousness and is pulseless. Despite attempts at cardiopulmonary resuscitation, he dies. Examination of the heart at autopsy shows complete occlusion of the left anterior descending artery with a red thrombus overlying a necrotic plaque. Which of the following pathophysiologic mechanisms is most likely responsible for this patient's acute coronary condition?
Q5
A 60-year-old man is brought to the emergency department by his wife with a sudden onset of right-sided weakness 2 hours ago. He can speak clearly without difficulty and denies any similar symptoms in the past. Past medical history is significant for hypertension and diabetes, both poorly managed due to medication non-compliance. Family history is significant for heart disease and diabetes in multiple paternal and maternal relatives. His vital signs include: blood pressure 150/88 mm Hg, pulse 86/min, and respiratory rate 15/min. On physical examination, strength is 3/5 on the right and 5/5 on the left upper and lower extremities. The sensation is intact, and no impairments in balance or ataxias are present. An initial noncontrast CT scan of the head is unremarkable, but a repeat noncontrast CT scan of the head performed a month later reveals the 2 lesions circled in the image. Which of the following is the most likely diagnosis in this patient?
Q6
A 74-year-old man presents with complaints of sudden severe crushing retrosternal pain. The pain radiated to his left arm shortly after it began, and he was subsequently rushed to the emergency department for evaluation. His troponins and creatine kinase-MB (CK-MB) were elevated. Unfortunately, the patient died within the next 2 hours and an autopsy was performed immediately. The gross examination of the heart will show?
Q7
A 79-year-old homeless man is brought to the emergency department by ambulance 30 minutes after being found unresponsive by the police. On arrival, he is apneic and there are no palpable pulses. Despite appropriate life-saving measures, he dies. Examination of the heart during autopsy shows normal ventricles with a sigmoid-shaped interventricular septum. A photomicrograph of a section of the heart obtained at autopsy is shown. Which of the following is the most likely underlying cause for the structure indicated by the arrow?
Q8
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?
Q9
A 48-year-old man with a lengthy history of angina is brought to the emergency department after the acute onset of severe chest pain that started 40 minutes ago. Unlike previous episodes of chest pain, this one is unresponsive to nitroglycerin. His medical history is significant for hypertension, type 2 diabetes mellitus, and hyperlipidemia. His current medications include lisinopril, metformin, and simvastatin. His blood pressure is 130/80 mm Hg, heart rate is 88/min, respiratory rate is 25/min, and temperature is 36.6°C (97.8°F). An ECG shows ST-segment elevation in leads avF and V1-V3. He is administered aspirin, nasal oxygen, morphine, and clopidogrel; additionally, myocardial reperfusion is performed. He is discharged within 2 weeks. He comes back 3 weeks later for follow-up. Which of the following gross findings are expected to be found in the myocardium of this patient at this time?
Q10
A 50-year-old man is brought to the hospital after being found unresponsive in his bed in the morning. He is declared dead on arrival in the emergency room. His wife states that he always had uncontrolled hypertension despite being on multiple medications. An autopsy is performed, and the cause of his death is found to be a hemorrhage in his right basal ganglia. On microscopic examination, the branches of the renal artery have concentric endothelial proliferation with prominent narrowing of the lumen resulting in focal ischemia and hemorrhage of the renal parenchyma. Which of the following is most likely related to the findings in this patient?
Cardiovascular US Medical PG Practice Questions and MCQs
Question 1: A 14-year-old Caucasian female with a family history of familial hypercholesterolemia commits suicide by drug overdose. Her family decides to donate her organs, and her heart is removed for donation. After removing the heart, the cardiothoracic surgeon notices flat yellow spots on the inside of her aorta. Which of the following cell types predominate in these yellow spots?
A. Fibroblasts
B. T-cells
C. Macrophages (Correct Answer)
D. Neutrophils
E. Endothelium
Explanation: ***Correct: Macrophages***
- The "flat yellow spots" on the aorta in a familial hypercholesterolemia patient are characteristic of **fatty streaks**, the earliest lesions of atherosclerosis.
- These fatty streaks are primarily composed of **lipid-laden macrophages**, also known as **foam cells**, which have ingested oxidized low-density lipoprotein (LDL).
- In familial hypercholesterolemia, elevated LDL levels accelerate the formation of these macrophage-rich lesions even in young patients.
*Incorrect: Fibroblasts*
- While fibroblasts are involved in the later stages of **atherosclerotic plaque formation** by synthesizing collagen and forming a fibrous cap, they are not the predominant cell type in early fatty streaks.
- Their presence signifies a more advanced, **fibrotic lesion**, not the initial yellow spots.
*Incorrect: T-cells*
- T-cells are involved in the inflammatory response in **atherosclerosis** and are found within plaques, but they are not the dominant cell type forming the bulk of the initial lipid accumulation in fatty streaks.
- They contribute to the **immune-mediated aspects** of plaque progression.
*Incorrect: Neutrophils*
- Neutrophils are primarily involved in **acute inflammation** and bacterial infections.
- They are generally not a prominent cell type in either early or advanced **atherosclerotic lesions** under normal circumstances.
*Incorrect: Endothelium*
- Endothelial cells line the lumen of blood vessels and are crucial in the **initiation of atherosclerosis** by becoming dysfunctional and allowing LDL entry.
- However, they do not constitute the "yellow spots" themselves, which are subendothelial accumulations of lipids and immune cells.
Question 2: A 51-year-old man comes to the physician for the evaluation of a 3-week history of fatigue and shortness of breath. One year ago, a screening colonoscopy showed colonic polyps. His brother has a bicuspid aortic valve. On examination, a late systolic crescendo-decrescendo murmur is heard at the right upper sternal border. Laboratory studies show:
Hemoglobin 9.1 g/dL
LDH 220 U/L
Haptoglobin 25 mg/dL (N = 41–165 mg/dL)
Urea nitrogen 22 mg/dL
Creatinine 1.1 mg/dL
Total bilirubin 1.8 mg/dL
A peripheral blood smear shows schistocytes. Which of the following is the most likely cause of this patient's anemia?
A. Erythrocyte membrane fragility
B. Fragmentation of erythrocytes (Correct Answer)
C. Erythrocyte enzyme defect
D. Gastrointestinal bleeding
E. Autoimmune destruction of erythrocytes
Explanation: ***Fragmentation of erythrocytes***
- The presence of **schistocytes** on peripheral blood smear, along with signs of **hemolysis** (elevated LDH, decreased haptoglobin, elevated bilirubin), points to **microangiopathic hemolytic anemia**.
- The late systolic crescendo-decrescendo murmur at the right upper sternal border, combined with a family history of **bicuspid aortic valve**, strongly suggests **aortic stenosis**, which can cause **shear stress** and fragmentation of red blood cells as they pass through the narrowed valve.
*Erythrocyte membrane fragility*
- While membrane fragility can cause hemolytic anemia, conditions like **hereditary spherocytosis** or **elliptocytosis** would typically present with specific red cell morphologies (spherocytes, elliptocytes) rather than schistocytes.
- There are no other findings in the patient's history or lab results that would specifically suggest a primary membrane defect.
*Erythrocyte enzyme defect*
- Enzyme defects such as **G6PD deficiency** or **pyruvate kinase deficiency** lead to hemolytic anemia but typically do not cause **schistocytes**.
- These conditions are also often associated with specific triggers or presentations not evident here.
*Gastrointestinal bleeding*
- While a history of colonic polyps and anemia could suggest **gastrointestinal bleeding** (leading to iron deficiency anemia), this would typically present as a **microcytic hypochromic anemia** and would not cause **schistocytes**, elevated LDH, or decreased haptoglobin.
- The low hemoglobin could be partially due to blood loss, but the hemolytic markers point to a different primary cause for the anemia.
*Autoimmune destruction of erythrocytes*
- **Autoimmune hemolytic anemia** can cause significant anemia and hemolysis (elevated LDH, decreased haptoglobin, elevated bilirubin).
- However, it typically does not present with **schistocytes** but rather **spherocytes**, and a **direct Coombs test** would be positive, which is not mentioned here.
Question 3: A 38-year-old man comes to the physician because of a 3-week history of a painful rash affecting his left foot. For the past 2 years, he has had recurrent episodes of color changes in his fingers when exposed to the cold; his fingers first turn white and then progress to blue and red before spontaneously resolving. He has smoked two packs of cigarettes daily for 20 years. His blood pressure is 115/78 mm Hg. Physical examination shows multiple tender, dark purple nodules on the lateral surface of the left foot with surrounding erythema that follow the course of the lateral marginal vein. There are dry ulcers on the tip of his right index finger and on the distal aspect of his right hallux. Serum lipid studies show no abnormalities. Biopsy of the dorsalis pedis artery will most likely show which of the following findings?
A. Transmural inflammation with fibrinoid necrosis of the vessel wall
B. Calcification of the tunica media with foam cells and fibrous cap formation
C. Segmental thrombosing inflammation with sparing of the internal elastic lamina (Correct Answer)
D. Granulomatous inflammation with narrowing of the vessel lumen
E. Intraluminal fibrin clot predominantly composed of red blood cells
Explanation: ***Segmental thrombosing inflammation with sparing of the internal elastic lamina***
- The patient's history of **Raynaud phenomenon**, painful rash with **ulcers on digits**, and **heavy smoking (2 packs/day for 20 years)** strongly points to **Buerger disease (thromboangiitis obliterans)**.
- **Biopsy findings** characteristic of Buerger disease include acute and chronic inflammatory infiltrates, **segmental thrombosis** of arteries and veins, and **preservation of the internal elastic lamina**.
*Transmural inflammation with fibrinoid necrosis of the vessel wall*
- This finding is characteristic of **polyarteritis nodosa**, a necrotizing vasculitis affecting medium-sized arteries.
- While polyarteritis nodosa can cause skin lesions and mononeuropathy, **Raynaud phenomenon** and strong association with **smoking** are not typical features.
*Calcification of the tunica media with foam cells and fibrous cap formation*
- This describes features of **atherosclerosis** (fibrous cap formation with foam cells in the intima) and **Mönckeberg arteriosclerosis** (calcification of the tunica media).
- Atherosclerosis typically involves larger arteries, and while it can lead to peripheral arterial disease and ulcers, the specific pattern of recurrent Raynaud phenomenon and tender nodules in a young smoker is less consistent.
*Granulomatous inflammation with narrowing of the vessel lumen*
- This is a hallmark of **giant cell arteritis** or **Takayasu arteritis**, both of which are large-vessel vasculitides, but neither fit the clinical presentation.
- Giant cell arteritis primarily affects temporal arteries in older adults, and Takayasu arteritis typically involves the aorta and its major branches in younger women, presenting with claudication and absent pulses in limbs.
*Intraluminal fibrin clot predominantly composed of red blood cells*
- This describes a **thrombus**, which can be seen in various conditions, including deep vein thrombosis or arterial thrombosis related to atherosclerosis.
- While thrombosis is central to Buerger disease, this description is too generic and lacks the specific inflammatory and structural features seen on biopsy in thromboangiitis obliterans.
Question 4: A 73-year-old man with coronary artery disease and hypertension is brought to the emergency department by ambulance 90 minutes after the acute onset of substernal chest pain and dyspnea. He has smoked 2 packs of cigarettes daily for 52 years. Shortly after arriving at the hospital, he loses consciousness and is pulseless. Despite attempts at cardiopulmonary resuscitation, he dies. Examination of the heart at autopsy shows complete occlusion of the left anterior descending artery with a red thrombus overlying a necrotic plaque. Which of the following pathophysiologic mechanisms is most likely responsible for this patient's acute coronary condition?
A. Influx of lipids into the endothelium
B. Secretion of matrix metalloproteinases (Correct Answer)
C. Release of platelet-derived growth factor
D. Type III collagen deposition
E. Proliferation of smooth muscle cells
Explanation: ***Secretion of matrix metalloproteinases***
- **Matrix metalloproteinases (MMPs)** degrade the **extracellular matrix** within the fibrous cap of an atherosclerotic plaque, leading to its **destabilization and rupture**.
- Plaque rupture then exposes the highly thrombogenic lipid core, initiating thrombus formation and acute coronary events like the **red thrombus** seen in the **left anterior descending artery (LAD)**.
*Influx of lipids into the endothelium*
- This process is characteristic of the **initial stages of atherosclerosis**, leading to **fatty streak formation**, not the acute plaque rupture and thrombosis described.
- While essential for plaque development, lipid influx alone does not directly explain aggressive plaque rupture and acute thrombus formation.
*Release of platelet-derived growth factor*
- **Platelet-derived growth factor (PDGF)** is primarily involved in **smooth muscle cell proliferation** and migration, contributing to plaque growth and thickening.
- Its role is more chronic and proliferative, not immediate plaque destabilization and rupture leading to acute thrombosis.
*Type III collagen deposition*
- **Type III collagen** is characteristic of early, developing atherosclerotic plaques and granulation tissue, contributing to plaque stability.
- Plaque vulnerability associated with rupture involves a **thin fibrous cap** with reduced **collagen content**, often due to increased collagen degradation.
*Proliferation of smooth muscle cells*
- **Smooth muscle cell proliferation** occurs during chronic atherosclerosis, contributing to the **fibrous cap formation** and overall plaque stability.
- In the context of acute plaque rupture, it is the *erosion* of the fibrous cap, often due to degradation, rather than proliferation, that is the immediate cause.
Question 5: A 60-year-old man is brought to the emergency department by his wife with a sudden onset of right-sided weakness 2 hours ago. He can speak clearly without difficulty and denies any similar symptoms in the past. Past medical history is significant for hypertension and diabetes, both poorly managed due to medication non-compliance. Family history is significant for heart disease and diabetes in multiple paternal and maternal relatives. His vital signs include: blood pressure 150/88 mm Hg, pulse 86/min, and respiratory rate 15/min. On physical examination, strength is 3/5 on the right and 5/5 on the left upper and lower extremities. The sensation is intact, and no impairments in balance or ataxias are present. An initial noncontrast CT scan of the head is unremarkable, but a repeat noncontrast CT scan of the head performed a month later reveals the 2 lesions circled in the image. Which of the following is the most likely diagnosis in this patient?
A. Charcot-Bouchard aneurysm
B. Arteriovenous malformations
C. Hyaline arteriosclerosis (Correct Answer)
D. Hypertensive encephalopathy
E. Carotid artery atherosclerosis
Explanation: ***Hyaline arteriosclerosis***
- The patient's history of **poorly controlled hypertension and diabetes** are major risk factors for **hyaline arteriosclerosis**, which leads to vessel wall thickening and narrowing, commonly affecting small perforating arteries in the brain.
- This condition is a primary cause of **lacunar infarcts**, which manifest as small, deep brain lesions consistent with the patient's presentation of **right-sided weakness (pure motor stroke)** and the later CT findings.
*Charcot-Bouchard aneurysm*
- These aneurysms are associated with **chronic hypertension** and occur in small cerebral arteries, often leading to **intracerebral hemorrhage** when they rupture.
- While associated with hypertension, the clinical presentation here is more consistent with an **ischemic event (lacunar stroke)** rather than hemorrhage, and the CT findings a month later show chronic ischemic changes.
*Arteriovenous malformations*
- **Arteriovenous malformations (AVMs)** are congenital vascular abnormalities that can present with seizures, headaches, or hemorrhage, but they typically manifest as a **tangle of abnormal blood vessels** on imaging rather than small, punctate lesions indicative of infarction.
- The sudden onset of focal neurological deficits followed by the detection of small lesions on CT is less characteristic of an AVM.
*Hypertensive encephalopathy*
- **Hypertensive encephalopathy** is a serious complication of severe, rapid-onset hypertension, characterized by symptoms like **headache, confusion, seizures, and visual disturbances**, often with cerebral edema on imaging.
- The patient's chronic poorly controlled hypertension and presentation of isolated focal weakness, without signs of rapid systemic decompensation or global neurological dysfunction, do not align with hypertensive encephalopathy.
*Carotid artery atherosclerosis*
- **Carotid artery atherosclerosis** typically causes neurological symptoms through **artery-to-artery embolism** or **hemodynamic insufficiency**, leading to larger ischemic strokes, often involving the cerebral cortex.
- The patient's symptoms of **pure motor weakness** and the small, deep lesions seen on follow-up CT are more indicative of a lacunar stroke affecting deeper brain structures rather than a large cortical infarct resulting from carotid emboli.
Question 6: A 74-year-old man presents with complaints of sudden severe crushing retrosternal pain. The pain radiated to his left arm shortly after it began, and he was subsequently rushed to the emergency department for evaluation. His troponins and creatine kinase-MB (CK-MB) were elevated. Unfortunately, the patient died within the next 2 hours and an autopsy was performed immediately. The gross examination of the heart will show?
A. White, patchy, non-contractile scar
B. Normal heart tissue (Correct Answer)
C. Pallor of the infarcted tissue
D. Abundant neutrophils
E. Red granulation tissue surrounding the infarction
Explanation: ***Normal heart tissue***
- At **0-4 hours** following a myocardial infarction, the heart muscle shows **no gross changes** on autopsy examination.
- Although **coagulative necrosis** begins at the cellular level within minutes, these microscopic changes are **not visible** to the naked eye during gross examination.
- The patient died within **2 hours** of symptom onset, which falls within this early window where the heart appears **grossly normal** despite the acute infarction.
- Elevated **cardiac enzymes** (troponins, CK-MB) confirm myocardial injury has occurred, but gross pathological changes lag behind biochemical and microscopic changes.
*Pallor of the infarcted tissue*
- **Pallor** (pale discoloration) of infarcted myocardium typically becomes visible on gross examination at **4-12 hours** post-infarction.
- At 2 hours, this change has not yet developed sufficiently to be visible on gross inspection.
- Pallor results from **edema** and the accumulation of dead cells, which takes several hours to manifest grossly.
*White, patchy, non-contractile scar*
- A **white fibrotic scar** is characteristic of a **healed myocardial infarction**, which takes **several weeks to months** to form.
- This represents complete replacement of necrotic tissue by **collagenous scar tissue** (fibrosis).
- This is a chronic finding, not an acute one.
*Abundant neutrophils*
- **Neutrophil infiltration** is a microscopic finding that typically begins around **12-24 hours** after infarction, becoming abundant over the following days.
- Even when present, neutrophils are not visible on **gross examination**—they require microscopic evaluation.
- At 2 hours post-infarction, neutrophils have not yet migrated to the infarcted area.
*Red granulation tissue surrounding the infarction*
- **Granulation tissue** formation begins around **3-7 days** after infarction and involves proliferation of **capillaries** and **fibroblasts**.
- Grossly, this appears as a **hyperemic border** with central yellow softening.
- This represents the healing phase and would not be present within 2 hours of symptom onset.
Question 7: A 79-year-old homeless man is brought to the emergency department by ambulance 30 minutes after being found unresponsive by the police. On arrival, he is apneic and there are no palpable pulses. Despite appropriate life-saving measures, he dies. Examination of the heart during autopsy shows normal ventricles with a sigmoid-shaped interventricular septum. A photomicrograph of a section of the heart obtained at autopsy is shown. Which of the following is the most likely underlying cause for the structure indicated by the arrow?
A. Accumulation of iron granules
B. Clumping of defective mitochondria
C. Deposition of wild-type transthyretin (Correct Answer)
D. Aggregation of alpha-synuclein
E. Oxidation of phospholipid molecules
Explanation: ***Deposition of wild-type transthyretin***
- This photomicrograph likely shows amyloid deposition, and in an elderly patient with heart failure, **wild-type transthyretin (ATTR) amyloidosis** is the most common cause.
- The sigmoid-shaped interventricular septum also suggests age-related changes, often seen with ATTR amyloidosis.
*Accumulation of iron granules*
- **Hemochromatosis** involves iron deposition; however, it typically results in hemosiderin granules, which stain differently (e.g., Prussian blue), and the accompanying heart pathology would be **dilated cardiomyopathy**, not restrictive.
- While iron overload can affect the heart, its microscopic appearance is distinct from that of amyloid, and it is less likely to cause sudden death in this manner without other systemic signs.
*Clumping of defective mitochondria*
- **Mitochondrial myopathies** can cause cardiomyopathy, but the characteristic histological findings are often **ragged red fibers** on Gomori trichrome stain due to subsarcolemmal mitochondrial aggregates, not the diffuse extracellular deposits characteristic of amyloid.
- This is a rare cause of cardiomyopathy in the general elderly population and does not fit the typical macroscopic cardiac findings described.
*Aggregation of alpha-synuclein*
- **Alpha-synuclein aggregation** is characteristic of **Parkinson's disease** and other synucleinopathies, forming **Lewy bodies** primarily in neuronal tissue, not cardiac muscle.
- While autonomic dysfunction can occur in Parkinson's, and sometimes alpha-synuclein can be found in cardiac nerves, it does not cause widespread myocardial deposits leading to fatal restrictive cardiomyopathy.
*Oxidation of phospholipid molecules*
- **Oxidation of phospholipid molecules** is associated with cellular damage and inflammation, such as in **atherosclerosis** or **ischemic injury**.
- While oxidative stress plays a role in various cardiac pathologies, it does not lead to the formation of organized extracellular deposits in the myocardium that would resemble amyloid on histology.
Question 8: 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)
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.
Question 9: A 48-year-old man with a lengthy history of angina is brought to the emergency department after the acute onset of severe chest pain that started 40 minutes ago. Unlike previous episodes of chest pain, this one is unresponsive to nitroglycerin. His medical history is significant for hypertension, type 2 diabetes mellitus, and hyperlipidemia. His current medications include lisinopril, metformin, and simvastatin. His blood pressure is 130/80 mm Hg, heart rate is 88/min, respiratory rate is 25/min, and temperature is 36.6°C (97.8°F). An ECG shows ST-segment elevation in leads avF and V1-V3. He is administered aspirin, nasal oxygen, morphine, and clopidogrel; additionally, myocardial reperfusion is performed. He is discharged within 2 weeks. He comes back 3 weeks later for follow-up. Which of the following gross findings are expected to be found in the myocardium of this patient at this time?
A. Pale infarcted tissue
B. Coagulation necrosis
C. Yellow necrotic area
D. White scar tissue (Correct Answer)
E. Red granulation tissue
Explanation: ***White scar tissue***
- Three weeks post-MI, the healing process is advanced, characterized by the formation of **dense fibrous scar tissue**, which appears white.
- This scar tissue replaces the necrotic myocardium and is primarily composed of **collagen**, signifying the completion of the repair phase.
*Pale infarcted tissue*
- This finding is typical of an **acute myocardial infarction** during the initial hours to days, before significant inflammatory response or healing has occurred.
- At 3 weeks, the tissue would have undergone significant remodeling, and the infarct would no longer appear pale and unorganized.
*Coagulation necrosis*
- **Coagulation necrosis** is the hallmark microscopic feature of an acute ischemic injury, visible within hours to a few days after the infarct.
- Grossly, this might present as pallor, but at 3 weeks, the necrotic tissue would have been largely cleared or replaced.
*Yellow necrotic area*
- A **yellow necrotic area** usually appears around 3 to 10 days post-MI, as neutrophils begin to break down the dead myocardial cells.
- This reflects the peak of the inflammatory process and early reabsorption of necrotic debris, but it would have progressed further by 3 weeks.
*Red granulation tissue*
- **Red granulation tissue** begins to form within 1-2 weeks post-MI, as macrophages clear cellular debris and fibroblasts deposit collagen.
- While present, it would be transitioning into mature fibrous scar tissue by 3 weeks, which is predominantly white.
Question 10: A 50-year-old man is brought to the hospital after being found unresponsive in his bed in the morning. He is declared dead on arrival in the emergency room. His wife states that he always had uncontrolled hypertension despite being on multiple medications. An autopsy is performed, and the cause of his death is found to be a hemorrhage in his right basal ganglia. On microscopic examination, the branches of the renal artery have concentric endothelial proliferation with prominent narrowing of the lumen resulting in focal ischemia and hemorrhage of the renal parenchyma. Which of the following is most likely related to the findings in this patient?
A. Raised cholesterol level in the blood
B. Elevated ammonia level in the blood
C. Raised calcium level in the blood
D. Raised renin level in the blood (Correct Answer)
E. Elevated C-reactive protein in the blood
Explanation: ***Raised renin level in the blood***
- The patient had uncontrolled **hypertension** leading to a fatal **intracerebral hemorrhage** (typical location: basal ganglia). The key autopsy finding of **concentric endothelial proliferation** with lumen narrowing in renal arteries describes **hyperplastic (proliferative) arteriolosclerosis**, also known as **"onion-skinning"** - the hallmark of **malignant hypertension**.
- In malignant hypertension, severe vascular injury causes **renal ischemia**, which triggers massive activation of the **renin-angiotensin-aldosterone system (RAAS)**, leading to markedly **elevated renin levels**. This creates a vicious cycle: renin elevation → further hypertension → more vascular injury → more renin release.
- The combination of uncontrolled hypertension, intracerebral hemorrhage, and hyperplastic arteriolosclerosis strongly indicates a renin-driven hypertensive crisis.
*Raised cholesterol level in the blood*
- While hypercholesterolemia contributes to **atherosclerosis** and chronic vascular disease, it does not explain the acute pathological finding of **concentric endothelial proliferation (onion-skinning)**.
- Atherosclerosis involves **eccentric plaque formation** with lipid deposition, not the concentric smooth muscle and endothelial proliferation seen in malignant hypertension.
- The acute, severe nature of this patient's vascular changes points to hypertensive emergency, not atherosclerotic disease.
*Elevated ammonia level in the blood*
- **Hyperammonemia** is associated with **hepatic encephalopathy** due to severe liver dysfunction (cirrhosis, acute liver failure), which is not suggested by this patient's presentation.
- Elevated ammonia does not cause hypertension, intracerebral hemorrhage, or the specific renal vascular pathology (hyperplastic arteriolosclerosis) described.
*Raised calcium level in the blood*
- **Hypercalcemia** can cause nephrolithiasis, nephrocalcinosis, and various systemic symptoms, but it is not the primary driver of malignant hypertension or intracerebral hemorrhage.
- While chronic hypercalcemia may contribute to vascular calcification (medial calcific sclerosis), it does not produce the **acute proliferative vascular changes** (onion-skinning) characteristic of malignant hypertension.
*Elevated C-reactive protein in the blood*
- **CRP** is a non-specific inflammatory marker that may be elevated in many chronic conditions, including cardiovascular disease.
- However, CRP elevation is a **consequence** rather than a cause of vascular injury, and it does not explain the specific mechanism of malignant hypertension or the pathognomonic finding of hyperplastic arteriolosclerosis.
- The renin-angiotensin system activation is the primary pathophysiologic mechanism in this case.
