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Questions and Answers
Which of the following vessels are usually spared in atherosclerosis?
What is the composition of the central core of an atheromatous plaque?
What is the characteristic appearance of cholesterol in an atheromatous plaque under a microscope?
What is the effect of atherosclerosis on the media opposite the plaques?
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What is the consequence of artery stenosis due to atherosclerosis?
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Which of the following is a complication of atherosclerosis in the femoral and popliteal artery?
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What is the characteristic location of atherosclerotic lesions in vessels?
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What is a secondary change that can occur in an atheromatous plaque?
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What is the main underlying mechanism of rheumatic fever?
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What is the typical age range for the onset of rheumatic fever?
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What is the main complication of non-bacterial thrombotic endocarditis?
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What is the primary site of inflammation in rheumatic fever?
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What is the underlying factor contributing to the high prevalence of rheumatic fever in Egypt and low socio-economic developing countries?
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What is the common manifestation of active rheumatic fever?
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What is the type of streptococcus that causes rheumatic fever?
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What is the outcome of repeated attacks of rheumatic fever?
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What is the characteristic arrangement of vegetations in the mitral valve?
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What type of cells are primarily found in Aschoff bodies?
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What is the term for the skin rash that is often seen in this condition?
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What is the location of the mural endocardium that may show Aschoff bodies?
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What is the term for the fleeting arthritis that is seen in this condition?
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What is the characteristic microscopic feature of Aschoff bodies?
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What is the direction of blood flow in relation to the location of vegetations on the mitral valve?
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What is the characteristic location of subcutaneous nodules in this condition?
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What is the characteristic of myocardial damage in cases of complete coronary arterial occlusion?
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At what time do the earliest naked eye changes of myocardial infarction occur?
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What is the typical color of the infarcted area after 3-4 days?
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What is the characteristic of the peripheral zone of the infarcted area after 3-4 days?
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What is the characteristic of the scar tissue after 3 months?
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What is the common complication of transmural infarction?
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What is the location of the surviving subendocardial band of myocytes?
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What is the characteristic of the infarcted tissue under microscopy after 8-12 hours?
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What is a common symptom of myocardial infarction?
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Which of the following is NOT a cause of myocarditis?
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What is a valuable diagnostic technique for myocarditis?
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What is a common laboratory test for diagnosing myocardial infarction?
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What is a complication of myocarditis?
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What is a characteristic electrocardiographic change in myocardial infarction?
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What is a cause of myocarditis that is also a cause of cardiac failure?
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What is a procedure that may be performed to exclude coronary artery disease in myocarditis?
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Study Notes
Atherosclerosis
- Atherosclerosis affects only part of the circumference of vessels, resulting in eccentric lesions on cross-section.
- The most extensively involved vessels are the infrarenal abdominal aorta, coronary arteries, popliteal arteries, internal carotid arteries, and vessels of the circle of Willis.
- Vessels of the upper extremities are usually spared, as are the mesenteric and renal arteries, except at their ostia.
- Atheromatous plaques consist of a central lipid core covered by a fibrous cap of smooth muscle cells and collagen.
- The central core contains lipids, necrotic debris, lipid-laden macrophages (foam cells), fibrin, and other plasma proteins.
- The cholesterol appears as needle-shaped clefts due to dissolution during slide preparation.
- The shoulder region, where the fibrous cap meets the vessel wall, is more cellular and contains macrophages, T cells, and smooth muscle cells.
- Later, it shows neovascularization (proliferated small blood vessels).
- Secondary changes include ulceration, thrombosis, and calcification.
- The media opposite the plaques are thin due to smooth muscle atrophy and loss.
Effects and Complications
- Atherosclerosis can lead to artery stenosis, resulting in diminished tissue perfusion and ischemia, such as:
- Cardiac ischemia and angina pectoris
- Lower limb ischemia and intermittent claudication in femoral and popliteal artery lesions
- Non-bacterial thrombotic endocarditis can occur in prolonged debilitating diseases, representing a hypercoagulable state, and can be the source of systemic emboli.
Rheumatic Fever and Rheumatic Heart Disease
- Rheumatic fever is an inflammatory, immune-mediated multisystem disease affecting the heart, particularly in the form of pancarditis.
- It occurs as a complication of streptococcal pharyngitis and tonsillitis, usually in children and adolescents.
- The disease is endemic in Egypt and low socio-economic developing countries due to overcrowding, low resistance, and increased frequency of airborne respiratory tract infections.
- Acute rheumatic fever can progress to chronic rheumatic heart disease, mainly manifesting as valvular abnormalities.
- Valvular manifestations may begin to appear years after the first attack of rheumatic fever or after repeated attacks produce significant valve deformity.
Pathogenesis
- Acute rheumatic fever results from abnormal host immune responses to group A streptococcal antigens that cross-react with host proteins.
- Antibodies and CD4+ T cells directed against streptococcal M proteins recognize cardiac self-antigens.
Microscopic Picture
- Aschoff bodies are composed of lymphocytes and macrophages (caterpillar cells) around a focus of fibrinoid necrosis.
- The vegetations are arranged at the line of closure of the cusps in a regular linear pattern, firmly fixed to the valve, and present in the face of the direction of blood flow.
Extra-Cardiac Manifestations
- Fleeting arthritis: Large joints are red, painful, and swollen, resolving completely with no residual effect.
- Skin rash (erythema annulare or marginatum): Reddish macules with a pale center, seen particularly on the trunk.
- Subcutaneous nodules: 2-20 mm nodules with a microscopic picture similar to Aschoff bodies, usually over bony prominences.
Myocardial Infarction
- Morphology:
- Gross: Earliest changes occur around 15 hours, with the affected muscle appearing pale and swollen.
- Microscopic: The infarcted tissue shows coagulative necrosis after 8-12 hours.
- Clinical picture:
- Prolonged (more than 30 minutes) chest pain, associated with a rapid, weak pulse, profuse sweating, and nausea and vomiting.
- Dyspnea due to impaired contractility of the ischemic myocardium and resultant pulmonary congestion and edema.
- Laboratory tests: Elevation of cardiac-specific troponins and cardiac fraction of creatine kinase.
Myocarditis
- Definition: Inflammation of the cardiac muscle.
- Causes:
- Acute rheumatic carditis
- Viral infections (e.g., Coxsackie virus, adenovirus, influenza, and HIV)
- Bacterial infections (e.g., diphtheria, clostridia)
- Parasitic infections (e.g., Chagas' disease)
- Ionizing radiation
- Drugs (e.g., doxorubicin)
- Clinical features:
- In most patients, myocarditis is a self-limiting condition with only mild chest pain and fatigue.
- Cardiac magnetic resonance imaging is a valuable diagnostic technique.
- Fatalities are relatively uncommon, and cardiac failure may develop.
- An endomyocardial biopsy may show lymphocytic infiltration and myocyte necrosis.
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Description
This quiz covers the sites of atherosclerosis in the vascular system, including the abdominal aorta, coronary arteries, and more. Learn about the extent of lesions in different vessels.
