This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'The percentage of pulmonary emboli, that proceed to an infraction, is approximate - \nSelect and explain. \nA. 0-5%, B. 5-15%, C. 20-30%, D. 30-40%', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Only about 10% of emboli actually cause infarction- Regarding morphologic consequences of embolic occlusion of\xa0pulmonary arteries - Robbins 7th/742\nWhy only 10% of emboli cause infarction?\n\nBecause the lungs have a dual blood supply.\nIn patients with adequate cardiovascular function, the bronchial arterial supply can often sustain the lung parenchyma despite obstruction to the pulmonary arterial system.\nPulmonary embolism usually causes infarction only when the circulation is already inadequate as in patients with heart or lung disease.\nFor this reason, pulmonary infarcts tend to be uncommon in the young.\n\nConsequences of pulmonary embolism\n\nThe effects of pulmonary embolism depend mainly on the size of the occluded vessel, the number of emboli, and on cardiovascular status of the patients.\nThe following consequences can result.\n\n1. Asymptomatic\n\nMost pulmonary emboli (60% to 80%) are clinically silent because they are small.\nWith time, they undergo organization and are incorporated into the vascular wall.\n\n2.\xa0\xa0 Sudden death (cardiovascular collapse)\n\nMassive pulmonary embolism may result in instantaneous death, without occurrence of chest pain and dyspnea.\n\n3.\xa0\xa0 Acute cor pulmonale (Acute right heart failure)\n\nNumerus small emboli may obstruct most of the pulmonary circulation resulting in acute heart failure.\n\n4.\xa0\xa0 Pulmonary infarction\n\nEmbolic obstruction of small end-arteriolar pulmonary branches can cause pulmonary infarction.\nAbout three-fourths of all infarcts affect the lower lobes, and in more than half, multiple lesions occur.\nCharacteristically, they extend to the periphery of the lung substance as a wedge with the apex pointing toward the kilns of the lung.\nThe pulmonary infarct is classically hemorrhagic infarct.\n\n5.\xa0\xa0 Pulmonary hemorrhage\n\nEmbolic obstruction of medium-sized arteries may result in pulmonary hemorrhage.\n\n6.\xa0\xa0 Pulmonary hypertension\n\nMultiple emboli over time may cause pulmonary hypertension with right heart failure.', 'role': 'assistant'}]