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 7 year old child presents with non productive cough, mild stridor since 6 months. On oral antibiotics, patient is improving but suddenly develops wheezing, productive cough, mild fever. X–ray shows hyperlucency and PFT shows obstructive curve. Most probable diagnosis is – \nSelect and explain. \nA. Post viral syndrome, B. Bronchiolitis obliterans, C. Follicular bronchitis, D. Pulmonary alveolar microlithiasis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Bronchiolitis obliterans\n\nBronchiolitis obliterans. is a rare chronic lung disease of the bronchioles and smaller airways\nBronchiolitis obliterans most commonly occurs in pediatric population after respiratory infections (i.e. adenovirus, mycoplasma, measles, influenza, pertussis).\nOther causes include connective tissue disease (i.e. juvenile rheumatoid arthritis, systemic lupus erythematosis, scleroderma)\nBronchiolitis occurs in all age groups.\n\n\nPathogenesis\n\nAfter the initial insult, inflammation affecting terminal bronchioles, respiratory bronchioles and alveolar ducts may result in obliteration of the airway lumen.\nEpithelial damage resulting in abnormal repair is characteristic of bronchiolitis obliterans.\nComplete or partial obstruction of the airway lumen may result in air trapping or atelactasis.\n\nClinical manifestations\n\nCough, fever, cyanosis and respiratory distress followed by initial improvement may be the initial signs of bronchiolitis obliterans.\nProgression of the disease may ensue with increasing dyspnoea, cough, sputum production and wheezing.\nChest radiographs may be relatively normal compared with the extent of physical findings but may demonstrate hyperluscency and patchy infiltrates (occasionally, a swyer James syndrome, i.e. a unilateral hyperluscent lung has developed).\nPulmonary function tests demonstrate varaible findings but typically shows signs of airway obstruction.\nVentilation perfusion scan shows a typical motheaten appearance of multiple matched defects in ventilation and perfusion.\nCT scan demonstrates patchy areas of hyperluscency.\nOpen lung biopsy or transbronchial biopsy remains the best means of establishing the diagnosis of bronchiolitis obliterans.\n\nTreatment\n\nNo definite therapy exists for bionchiolitis obliterans.\nAdministration of corticosteroids may be beneficial\n\nAbout other options\nFollicular bronchitis\n\nIt is a lyinphoproliferative lung disorder characterized the presence of lymphoid follicles, coursing along the airways (bronchi or bronchioles)\nIt is rare in children.\nAlthough the cause is unknown, an infectious aetiology has been proposed.\nOnset of symptoms generally occurs by 6 weeks of age and peaks between 6 and 18 months.\nCough, moderate fever and fine crackles are common clinical findings.\nFine crackles generally, persist over time and recurrence of symptoms is common.\nChest radiographs may be relatively benign initially but evolve into the typical interstitial pattern.\nPulmonary function tests show restrictive pattern\nChest CT shows fine reticular pattern.\nOpen lung biopsy is used to make definitive diagnosis.\n\n\nPulmonary alveolar microlithiasis\n\n\nThis is a rare disorder.\nAlthough the underlying cause of pulmonary alveolar microlithiasis is unknown, the disease is characterized by the formation of lamellar concretions of calcium phosphate or "inicrolith", within the alveoli, creating a classic pattern on the radiograph.\nChest radiography typically reveal bilateral infiltrates with a fine sandlike micronodular appearance.\nAlthough the mean age at the time of diagnosis is in the mid 30s the onset of the disease can occur during childhood.\nWhen symptomatic, individuals with pulmonary alveolar microlithiasis usually complain of dyspnoea on exertion and non productive cough.\nPhysical examinations of the lungs may reveal fine inspiratory crackles and diminished breath sounds. Clubbing occurs, although this is usually a more advanced sign.\nChildren are often asymptomatic on initial presentation.\nDiagnosis\nChest radiography typically reveals b/L infiltrate with a fine sandlike micronodular appearance or "Sandstorm" appearance.\nCT scan shows diffuse micronodular calcified densities.\nOpen lung biopsy reveals laminated calcific ioncretions within the alceoli.', 'role': 'assistant'}]