A 50-year-old man with familial hyperlipidemia undergoes resection of an abdominal aortic aneurysm. Signs of congestive heart failure develop shortly after surgery. Despite treatment, the patient becomes hypotensive and expires 2 days later. Autopsy reveals marked narrowing of coronary arteries, but without thrombosis. Multiple foci of necrosis are found circumferentially around the inner walls of both ventricles. Which of the following best describes the pathogenesis of necrotic foci in the patient's heart?
Dilated cardiomyopathy
Hypertensive heart disease
Restrictive cardiomyopathy
Subendocardial myocardial infarction
Transmural myocardial Infarction
The Correct Answer is D
A. Dilated cardiomyopathy: Dilated cardiomyopathy is characterized by ventricular dilation and systolic dysfunction, often idiopathic or secondary to toxins, infection, or genetics. It does not cause discrete necrotic foci circumferentially along the inner ventricular walls, as described in this patient.
B. Hypertensive heart disease: Hypertensive heart disease causes left ventricular hypertrophy and increased myocardial workload. While it can predispose to ischemia, it does not typically produce acute circumferential subendocardial necrosis in multiple foci without coronary thrombosis.
C. Restrictive cardiomyopathy: Restrictive cardiomyopathy is characterized by impaired diastolic filling due to stiff ventricles, often from infiltrative diseases. It does not produce myocardial necrosis or ischemic lesions of the subendocardium.
D. Subendocardial myocardial infarction: Subendocardial infarction results from inadequate perfusion of the inner layers of the myocardium, which are most vulnerable to ischemia. In patients with severe coronary artery narrowing without thrombosis, global hypoperfusion—such as post-surgical hypotension—can cause multiple foci of circumferential necrosis in the subendocardial region, consistent with this patient’s autopsy findings.
E. Transmural myocardial infarction: Transmural infarction involves full-thickness necrosis of the ventricular wall, typically due to acute coronary artery occlusion by thrombosis. The absence of thrombosis and the limited necrosis to the inner myocardial layer make transmural infarction unlikely in this case.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
A. Bacterial endocarditis:Bacterial endocarditis causes vegetations on heart valves, fever, and potential embolic events. It does not typically lead to chronic pulmonary congestion with hemosiderin-laden macrophages in alveoli, making it an unlikely cause of this lung pathology.
B. Bronchial asthma:Asthma is characterized by reversible airway obstruction, eosinophilic inflammation, and bronchospasm. It does not produce hemosiderin-laden macrophages or chronic pulmonary congestion associated with heart failure.
C. Congestive heart failure:In left-sided heart failure, elevated pulmonary venous pressure leads to chronic passive congestion. Red blood cells leak into alveoli and are phagocytosed by macrophages, forming hemosiderin-laden “heart failure cells.” The presence of these cells indicates chronic pulmonary congestion due to congestive heart failure.
D. Myocardial infarction:Myocardial infarction can lead to acute left ventricular dysfunction, but the presence of chronic hemosiderin-laden macrophages suggests a long-standing process rather than an acute event. While MI can precipitate heart failure, the autopsy finding reflects chronic congestion.
E. Pulmonary thromboembolism:Pulmonary embolism causes sudden obstruction of pulmonary arteries, leading to acute dyspnea, hypoxemia, or infarction. It does not typically result in chronic hemosiderin deposition in alveolar macrophages.
Correct Answer is D
Explanation
A. Chylothorax:Chylothorax is the accumulation of lymphatic fluid in the pleural space, usually due to thoracic duct injury or obstruction. It affects the thoracic cavity and does not cause isolated swelling of a limb after mastectomy.
B. Fibrinous exudate:Fibrinous exudate occurs in inflammatory conditions, such as infections or serositis, and contains fibrin strands. It is usually associated with body cavities rather than chronic soft tissue swelling of an extremity.
C. Hydrothorax:Hydrothorax refers to non-inflammatory fluid accumulation within the pleural cavity. It does not involve the soft tissues of the arm and is unrelated to post-mastectomy limb swelling.
D. Lymphedema:Lymphedema is the accumulation of protein-rich interstitial fluid in soft tissues due to impaired lymphatic drainage. After axillary lymph node dissection, the normal lymphatic pathways from the arm are disrupted, leading to progressive swelling, especially by the end of the day or with activity.
E. Serous exudate:Serous exudate is a thin, protein-rich fluid typically seen in acute inflammation or blister formation. It does not cause chronic limb swelling after lymphatic disruption, making it less appropriate for this patient’s presentation.
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