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: Pediatrics
[{'content': 'A child with three days history of upper respiratory tract infection presents with stridor, which decreases on lying down position. What is the most probable diagnosis – \nSelect and explain. \nA. Acute Epiglottitis, B. Laryngotracheobronchitis, C. Foreign body aspiration, D. Retropharyngeal abscess', 'role': 'user'}, {'content': 'Answer: B \nExplanation: This child has : -\n\n3 days history of upper respiratory tract infection.\nFollowed by stridor\n\nThese features suggest the diagnosis of croup.\nClinical manifestations of Croup \n\nMost patients have an upper respiratory tract infection with some combination of -\nRhinorrhea \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0\xa0\nA mild cough\xa0\xa0\xa0\xa0\xa0\nPharyngitis\xa0\nLow-grade fever\xa0 \xa0 \xa0 \xa0 \xa0\nAfter 1-3 days signs and symptoms of upper respiratory tract obstruction become apparent -\nBarking cough\nHoarseness\xa0\xa0\nInspiratory stridor\xa0\xa0\xa0\xa0\xa0\xa0\xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0\nSymptoms are characteristically worse at night.\nSymptoms often recur with decreasing intensity for several days and resolve completely in one week.\nAgitation and crying aggravate the symptoms.\nThe child may prefer to sit up in bed or be held upright.\n\n\nChest X-ray\n\nCharacteristic narrowing of the subglottic region known as the steeple sign.', 'role': 'assistant'}]