1-year-old male baby came to the hospital for "fever and cough for 4 days"; Mainly paroxysmal cough, sputum expectoration, yellow sticky sputum can be seen in the airway clearing, accompanied by nasal congestion, runny nose, and poor spirits. ; Physical examination: Breathing 30 times / min, heart rate 126 times / min, body temperature 39.0 °C, clear mind, throat congestion, breath is still stable, respiratory sounds of both lungs are rough, neutral moist rales can be heard in the right lower lung, no obvious abnormality is found in cardiac physical examination. Laboratory data: blood analysis: WBC 15.6*10^9/L, N 75%, L 21%, CRP 20mg/L; PPD test (-) 1. What is the diagnosis of this child and why? 2. What further checks are needed? 3. What diseases need to be differentiated from? 4. Briefly describe the principles and methods of treatment?
