Q. A 4-year-old child was brought to the emergency department by her mother. She states that her child has been coughing, wheezing and experiencing shortness of breath for the past 6 hours. Past medical history includes eczema and allergic rhinitis. The patient’s family history is unremarkable. Blood pressure is 110/65 mmHg, heart rate 110/min, and respiration rate 35/min. The patient is afebrile. Chest x-ray shows hyperinflated lung fields. The patient’s mother adds that a similar episode occurred last winter. What is the most likely diagnosis?