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 commonest cause of lung abscess - \nSelect and explain. \nA. Tuberculosis, B. Congenital, C. Hematogenous, D. Aspirated oropharyngeal secretion', 'role': 'user'}, {'content': 'Answer: D \nExplanation: \u200bLung abscess\xa0\n\nThe term pulmonary abscess describes a local suppurative process within the lung, characterized by necrosis of\xa0lung tissues.\n\nEtiology \n\nAspiration is the most common cause, factors that portend an increased risk of aspiration include esophageal dysmotility, seizure disorders, and neurological conditions causing bulbar dysfunction.\nAs an aspiration of oropharyngeal secretions is the most common cause, organisms most commonly causing lung\xa0abscess are those normally found in the oral cavity, i.e., Anaerobic bacteria (Bacteroides, Fusobacterium,\xa0peptococcus species).\n\nOther organisms are S. aureus, Klebsiella, Nocardia and gram-negative bacteria.\nMorphology\n\nPulmonary abscesses due to aspiration are more common on the right side because of the more vertical direction of the right main bronchus.\nMost often abscess is single.\nThe cardinal histologic change in all abscesses is the suppurative destruction of the lung parenchyma within the central area of cavitation.', 'role': 'assistant'}]