A baby with a cough

A 12 week old baby boy of South East Asian ethnicity was admitted in winter with a three day history of cough, coryza, rapid breathing, and reduced feeding. The initial diagnosis was bronchiolitis. He deteriorated on the second day after admission with worsening respiratory distress. Testing for respiratory syncytial virus in his nasopharyngeal aspirate was negative, and he had normal inflammatory markers and white blood cell count. A chest radiograph was taken (fig 1⇓). He was started on intravenous amoxicillin because pneumonia was suspected. Fig 1 Day 1 Two days later he developed high grade fever and needed oxygen. While taking a history from his parents, they explained that the boy’s grandmother, who had looked after him since the first week of life, was visiting from Pakistan and was being investigated for chronic cough. (1) Fig 1⇑ shows an anteroposterior chest radiograph. The abnormalities are a …